bluuebunny/crossref_metadata_2025 huggingface dataset:
Urinary calcium excretion in severe preeclampsia and eclampsia
Authors: Ingec Metin , Nazik Hakan , Kadanali Sedat
Published: December 2005

Urinary calcium levels in women with mild preeclampsia, severe preeclampsia and eclampsia were evaluated in this study. We collected 24-h urine samples from 35 mild preeclamptic (Group 1), 30 severe preeclamptic (Group 2), and 17 eclamptic patients (Group 3). The control group (Group 4) consisted of 35 healthy pregnant women. Serum levels of total calcium and creatinine, and urinary calcium were measured. These values were compared in the four groups. The mean maternal age and parity were similar in all groups. There were no statistically significant differences in the serum levels of total calcium and creatinine (p>0.05). Urinary calcium excretion in patients with preeclampsia and eclampsia was significantly lower than in controls (p<0.0001). Urinary calcium levels between mild preeclampsia and severe pre-eclampsia, and severe preeclampsia and eclampsia were similar (p>0.05), but were lower in eclampsia than in mild preeclampsia (p<0.05). In conclusion, urinary calcium excretion is reduced in patients with severe preeclampsia or eclampsia. However, the decrease in urinary calcium excretion cannot be used to identify the severity of preeclampsia, or to predict impending eclampsia.
In vitro re-mineralization of demineralized bone matrix in human serum
Authors: Eskandari Metin Manouchehr , Gulcin Eskandari Hatice , Aktas Melih , Atik Ugur
Published: December 2005

The aim of this study was to develop an in vitro re-mineralization model in human serum. For this purpose a commercially produced demineralized human bone matrix (DBM) was incubated in samples of human serum pools obtained from two physiologically different groups. The first group consisted of young males and the second of older females. After incubation periods of 4 and 7days at 37°C, changes in the levels of calcium and inorganic phosphate content of the serum and DBM samples were measured. The results of the study showed that the change in mineral content of serum and DBM samples in both study groups was statistically significant. The decrease in serum calcium content and increase in DBM inorganic phosphate content were significant in the young group for longer incubation times. In the older group, both serum calcium and inorganic phosphate decreased and DBM mineral content increased for the same incubation time. When the two physiological groups were compared, statistically significant differences were identified for changes in mineral levels in both serum and the DBM samples. These data indicate that the mineral content of human serum decreases and that of DBM increases when these two materials are incubated together. These changes provide evidence for the re-mineralization of DBM. The model described here could also detect a difference in re-mineralization capability between two different groups of human sera.
Measurement of serum amyloid A1 (SAA1), a major isotype of acute phase SAA
Authors: Xu Yuanyuan , Yamada Toshiyuki , Satoh Takahiko , Okuda Yasuaki
Published: December 2005

Serum amyloid A (SAA), a plasma precursor of reactive amyloid deposits, is a multigene product. SAA1 and SAA2, with primary structures that are 93% identical (98 of 104 amino acids), behave as acute phase proteins, as demonstrated by their increasing levels in plasma. Heretofore, it has been understood that SAA1 predominates and functions as an isotype in plasma. However, accurate measurements differentiating the two isotypes have not been reported. In this study, using monoclonal antibodies specific for SAA1, we developed an enzyme-linked immunosorbent assay (ELISA) for SAA1. The levels and ratios of SAA1 in total SAA (TSAA) were investigated in healthy subjects and patients with rheumatoid arthritis (RA). The SAA1/TSAA ratio was 74±12% and 77±12% in healthy subjects and RA patients, respectively. In RA patients, the ratios were not influenced by SAA1 genotype, which has been proposed to affect plasma SAA values. The kinetics of SAA1 in inflamed patients undergoing hemodialysis was found to be parallel with total SAA and C-reactive protein. Finally, this study confirmed that SAA1 is a major isotype of acute phase SAA and may determine total SAA values. This specific assay could be used in the evaluation of SAA behavior in several clinical conditions.
Disturbed lipoprotein composition in non-dialyzed, hemodialysis, continuous ambulatory peritoneal dialysis and post-transplant patients with chronic renal failure
Authors: Kimak Elżbieta , Książek Andrzej , Solski Janusz
Published: December 2005

Studies were carried out in 183 non-dialyzed, 123 hemodialysis, 81 continuous ambulatory peritoneal dialysis and 35 post-transplant patients and in 103 healthy subjects as a reference group. Lipids and apolipoprotein (apo)AI and apoB were determined using Roche kits. An anti-apoB antibody was used to separate apoB-containing apoCIII and apoE-triglyceride-rich lipoprotein (TRL) in the non-high-density lipoprotein (non-HDL) fraction from apoCIIInonB and apoEnonB in the HDL fraction in four groups of patients with chronic renal failure (CRF) and healthy subjects. Multivariate linear regression analysis was used to investigate the relationship between triglyceride (TG) or HDL-cholesterol (HDL-C) concentrations and lipoproteins. Dyslipidemia varied according to the degree of renal insufficiency, the type of dialysis and therapy regime in CRF patients. Lipoprotein disturbances were manifested by increased TG, non-HDL-C and TRL concentrations, and decreased HDL-C and apoAI concentrations, whereas post-renal transplant patients showed normalization of lipid and lipoprotein profiles, except for TG levels and total apoCIII and apoCIIInonB. The present study indicates that CRF patients have disturbed lipoprotein composition, and that hypertriglyceridemia and low HDL-C concentrations in these patients are multifactorial, being secondary to disturbed lipoproteins. The method using anti-apoB antibodies to separate apoB-containing lipoproteins in the non-HDL fraction from non-apoB-containing lipoproteins in HDL can be used in the diagnosis and treatment of patients with progression of renal failure or atherosclerosis. The variability of TG and HDL-C concentrations depends on the variability of TRL and cholesterol-rich lipoprotein concentrations, but the decreases in TG and increases in HDL-C concentrations are caused by apoAI concentration variability. These relationships, however, need to be confirmed in further studies.
Measurement of serum testosterone using high-performance liquid chromatography/tandem mass spectrometry
Authors: Vicente Faye B. , Smith Frederick A. , Sierra Rafael , Wang Sihe
Published: December 2005

Low levels of serum testosterone typically found in women and children cannot be reliably measured by immunoassay. We developed a simple and sensitive method using high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS). Sample preparation involved protein precipitation of serum (1.0mL) with acetonitrile containing the internal standard (testosterone-
Quantitative bacterial micro-assay for rapid detection of serum phenylalanine on dry blood-spots: application in phenylketonuria screening
Authors: Vallian Sadeq , Moeini Hassan
Published: December 2005

Phenylketonuria is an inherited metabolic disease, which is characterized by an increased level of serum phenylalanine. Quantitative measurement of phenylalanine in the serum of phenylketonuria patients is necessary to confirm the disease, and to distinguish phenylketonuria from other forms of hyperphenylalaninemia. In this study, we report a rapid and inexpensive micro-assay for simultaneous detection and quantitative measurement of serum phenylalanine on dry blood-spots. Analysis of the standard curve showed a broad linear range for phenylalanine from 120 to 1800μmol/L. Application of this method, the standard Guthrie bacterial inhibition assay and a high-performance liquid chromatography (HPLC) method for analysis of 34 samples from phenylketonuria patients and control samples produced comparable results, with the regression equation Y=0.994X+0.996. The advantage of this method over the Guthrie bacterial inhibition assay is its ability to measure serum phenylalanine quantitatively without false positive results. The method was successfully applied to dried blood-spots, serum and whole blood. The cost per sample is approximately 20–50 US cents, which is much less than for HPLC and commercial enzyme kits. The method can be automated, and is thus suitable for neonatal and mass screening for phenylketonuria, especially in developing countries where funding is a limiting factor.
N-Terminal pro-brain natriuretic peptide: normal ranges in the pediatric population including method comparison and interlaboratory variability
Authors: Albers Stefanie , Mir Thomas S. , Haddad Munif , Läer Stephanie
Published: December 2005

The aim of the present study was the investigation of N-terminal pro-brain natriuretic peptide (NT-proBNP) in the pediatric population. This is essential for adequate monitoring and classification of pediatric patients with heart disease, but no consistent data are available yet. In addition, the comparability of two commercially available NT-proBNP assays and the inter-laboratory variability for the most suitable one were assessed. For this purpose, 408 subjects (1–29years) were included. NT-proBNP was determined with a non-competitive electrochemiluminescent immunoassay (Roche NT-proBNP; n=402) and a competitive enzyme-immunoassay (Biomedica NT-proBNP; n=402). Inter-laboratory variability was evaluated for the Roche assay by stepwise inclusion of four and 11 centers throughout Germany, respectively. Roche NT-proBNP ranged from 5.0 to 391.5ng/L, with higher values for younger children. The 97.5th (75th) percentile curve ranged from 319.9ng/L (231.2 ng/L, 1–3years) to 114.9ng/L (53.3 ng/L, 18years). In contrast, Biomedica NT-proBNP ranged from 253.7 to 7602.8 ng/L, with no significant age dependency. The mean difference between the assays was 1649.7ng/L (95% confidence interval 1546.3–1753.1ng/L). Inter-laboratory variability ranged from 6.5% to 3.8%, covering a range from 51.3 to 6618.1ng/L. The assay seems to influence the interpretation of resulting NT-proBNP values and therefore has to be chosen carefully. For the monitoring and classification of pediatric patients with congenital heart disease, age-based NT-proBNP values should be used.
A new quality control model using performance goals based on biological variation in External Quality Assurance Schemes
Authors: Mina Ashraf
Published: December 2005

A new quality control model using performance goals based on biological variation in External Quality Assurance Schemes (EQAS) is described. The proposed model aims to use assay (analytical) CV
The clinical usefulness of glucose tolerance testing in gestational diabetes to predict early postpartum diabetes mellitus
Authors: Weijers Rob N.M. , Bekedam Dik J. , Goldschmidt Henk M.J. , Smulders Yvo M.
Published: December 2005

We examined the clinical usefulness of antepartum clinical characteristics, along with measures of glucose tolerance, in Dutch multiethnic women with gestational diabetes mellitus (GDM) for their ability to predict type 2 diabetes within 6months of delivery (early postpartum diabetes). The present study comprised a cross-sectional 5-year investigation (1998–2003) of a consecutive series of 168 women with GDM identified by a two-stage protocol at 16–33weeks of gestation. The following data were collected for all women: age and gestational age at entry into the study; prepregnancy body mass index (BMI); ethnicity; obstetric and clinical history, including the onset of early postpartum diabetes; pregnancy outcome; level of fasting C-peptide; and glycemic parameters of 50-g 1-h glucose challenge test and 100-g 3-h oral glucose tolerance test (diagnostic OGTT). We used receiver operating characteristic (ROC) curve analysis to test the clinical usefulness of the glycemic parameters. A total of 11 women (6.5%) developed early postpartum diabetes. Apart from family history of diabetes (p=0.052), anthropometric, maternal, and neonatal clinical parameters showed no association with early postpartum diabetes in univariate analyses. The level of fasting glucose, and both the glucose challenge test and diagnostic OGTT post-load glucose levels and glucose areas were associated with early postpartum diabetes. ROC curve analysis identifiedall three glucose challenge-test parameters, including fasting glucose concentration, as poor diagnostic tests, with a positive predictive value of ∼22%, whereas the positive predictive value associated with the area under the diagnostic OGTT curve increased progressively over monitoring time from 20.6% to 100%. Using a 3-h OGTT glucose area threshold of 35.7mmol·h/L resulted in 100% sensitivity and 100% specificity, identifying the 11 women who developed early postpartum diabetes. In summary, we can conclude from the present analysis that early postpartum diabetes is rare in GDM women (6.5%), and that the clinical usefulness of the total area under the diagnostic 3-h OGTT is superior to all other glycemic parameters for detecting early postpartum diabetes.
Analytical performance of a new two-step ADVIA Centaur® estradiol immunoassay during ovarian stimulation
Authors: Massart Catherine , Gibassier Jacqueline , Laurent Marie-Christine , Lannou Dominique Le
Published: December 2005

Measurement of estradiol is useful in women undergoing ovarian stimulation for in vitro fertilization and embryo transfer (IVF-ET). The analytical performance of a new two-step estradiol assay (ADVIA Centaur
EC4 European Syllabus for Post-Graduate Training in Clinical Chemistry and Laboratory Medicine: version 3 – 2005
Authors: Zerah Simone , McMurray Janet , Bousquet Bernard , Baum Hannsjorg , Beastall Graham H. , Blaton Vic , Cals Marie-Josèphe , Duchassaing Danielle , Gaudeau-Toussaint Marie-Françoise , Harmoinen Aimo , Hoffmann Hans , Jansen Rob T. , Kenny Desmond , Kohse Klaus P. , Köller Ursula , Gobert Jean-Gérard , Linget Christine , Lund Erik , Nubile Giuseppe , Opp Matthias , Pazzagli Mario , Pinon Georges , Queralto José M. , Reguengo Henrique , Rizos Demetrios , Szekeres Thomas , Vidaud Michel , Wallinder Hans
Published: December 2005

The EC4 Syllabus for Postgraduate Training is the basis for the European Register of Specialists in Clinical Chemistry and Laboratory Medicine.

The syllabus:

The syllabus is not primarily meant to be a training guide, but on the basis of the overview given (common minimal programme), national societies should formulate programmes that indicate where knowledge and experience is needed.

The main points of this programme are:

The aim of this version of the syllabus is to be in accordance with the Directive of Professional Qualifications published on 30 September 2005.

To prepare the common platforms planned in this directive, the disciplines are divided into four categories:
Twelve Common Deficiencies Found during Firestopping Inspections
Authors: Valiulis J , Phillips S
Published: January 2006

Twelve Common Deficiencies Found during Firestopping Inspections
Standards Development for Impermeable, Constructible, and Durable Waterproofing
Authors: Strong JC , Kovach JR , Eng VS
Published: January 2006

Building owners' expectations for waterproofing systems are simple. Waterproofing must prevent the passage of water (impermeability), must be capable of successful installation under typical construction conditions (constructability), and must continue to provide waterproofing for the life of the structure (durability). The realization of these expectations is thwarted, in part, by a lack of consensus on how these features are defined, tested, and compared to performance-based criteria. This investigation includes waterproofing materials commonly used on plazas and below-grade walls. The authors discuss important properties of waterproofing and review the requirements of standards for waterproofing systems. The results of testing bentonite and cold liquid-applied waterproofing are reported. In conclusion, the authors suggest improvements in standards.
Enhancing the Reliability of Evaluating Chloride Ingress in Concrete Using the ASTM C 1202 Rapid Chloride Penetrability Test
Authors: Bassuoni MT , Nehdi ML , Greenough TR
Published: January 2006

The rapid chloride penetrability test (RCPT-ASTM C 1202) is commonly used to evaluate the resistance of concrete to chloride ions ingress owing to its simplicity and rapidity. However, it has been criticized for various shortcomings such as giving favorable results to supplementary cementitious materials (e.g., silica fume), and bias against calcium nitrite corrosion inhibitors (CNI). Based on the ASTM C 1202 induced voltage concept, this study aims at enhancing the reliability of rapidly evaluating concrete resistance to chloride ions ingress. It is proposed that upon test termination, not only the passing charges are recorded, but the depth of chloride front migrating into concrete is also measured. Concrete mixtures herein were prepared incorporating selected materials (silica fume and CNI) that have been known to cause misleading results for the RCPT test. The effects of silica fume and CNI dosages on RCPT results were investigated and correlated to porosity trends evaluated by mercury intrusion porosimetry (MIP). The study reveals that measuring the migrating chloride front in concrete subsequent to the ASTM C 1202 test can eliminate the bias induced by electrolysis conductivity resulting from silica fume and/or CNI. This improves the reliability of assessing concrete resistance to chloride ions penetration using the RCPT procedure.
Empiric Use of Ampicillin and Cefotaxime, Compared With Ampicillin and Gentamicin, for Neonates at Risk for Sepsis Is Associated With an Increased Risk of Neonatal Death
Authors: Clark Reese H. , Bloom Barry T. , Spitzer Alan R. , Gerstmann Dale R.
Published: January 2006

BACKGROUND. We reported previously that the use of cephalosporin among premature neonates increased the risk of subsequent fungal sepsis. As a result, we recommended that ampicillin and gentamicin be used as empiric coverage for early-onset neonatal sepsis while culture results are awaited.

OBJECTIVES. To describe antibiotic use during the first 3 days after birth for neonates admitted to the NICU and to evaluate the outcomes for neonates treated with 2 different antibiotic regimens.

METHODS. We assembled a cohort of inborn neonates, from our deidentified administrative database, who had documented exposure to ampicillin during the first 3 days after birth. Infants treated concurrently with cefotaxime or gentamicin were evaluated, to identify the factors that were associated independently with death before discharge, with both univariate and multivariate analyses.

RESULTS. There were 128914 neonates selected as the study cohort; 24111 were treated concurrently with ampicillin and cefotaxime and 104803 were treated concurrently with ampicillin and gentamicin. Logistic modeling showed that neonates treated with ampicillin/cefotaxime were more likely to die (adjusted odds ratio: 1.5; 95% confidence interval: 1.4–1.7) and were less likely to be discharged to home or foster care than were neonates treated with ampicillin/gentamicin. This observation was true across all estimated gestational ages. Other factors that were associated independently with death included immature gestational age, need for assisted ventilation on the day of admission to the NICU, indications of perinatal asphyxia or major congenital anomaly, and reported use of ampicillin/cefotaxime.

CONCLUSIONS. For patients receiving ampicillin, the concurrent use of cefotaxime during the first 3 days after birth either is a surrogate for an unrecognized factor or is itself associated with an increased risk of death, compared with the concurrent use of gentamicin.
Validation of Otoliths for Determining Age of Golden Perch, a Long-Lived Freshwater Fish of Australia
Authors: Stuart Ivor G.
Published: January 2006

Sectioned sagittal otoliths have been validated for age determinations of golden perch Macquaria ambigua to age 9. However, previous studies have estimated ages up to 26 years. I used two known-age fish of ages 20 and 22 years to confirm that sectioned otoliths are valid for estimating the true age of old golden perch. The present study has validated the periodicity and stability of annulus formation over a long period of time as well as the accuracy of the age estimates. Accurate age assessments and confirmation of the consistency of annulus formation over time (>20 years) are important for increasing confidence for managers of the remaining golden perch populations.
Effect of Early Membrane Removal on Regeneration of Class II Furcation Defects in Dogs
Authors: Macedo Guilherme O. , Souza Sérgio L.S. , Novaes Arthur B. , Grisi Marcio F.M. , Taba Mário , Palioto Daniela B.
Published: January 2006

Background: This study evaluated the influence of early removal of an expanded polytetrafluoroethylene (ePTFE) membrane on periodontal regeneration.

Methods: The third and fourth mandibular bicuspids of six healthy mongrel dogs were used. Class II furcation lesions were surgically created making lesions chronic for 21 days. Full flaps were elevated, and ePTFE membranes were adapted over the defects. The membranes were removed at 2 weeks on the experimental sides (test group [TGr]) and at 4 weeks on the control side (control group [CGr]). The dogs were sacrificed 12 weeks following placement of the membranes, and the teeth were histologically processed. Area measurements of new tissue (NT), epithelium (EP), connective tissue (CT), and new bone (NB) and linear measurements of bone height (BH) and new cementum (NC) were made. Wilcoxon signed rank test (P <0.05; N = 6) was carried out to determine differences between groups.

Results: The area measurements (in mm2) for TGr and CGr, respectively, were as follows: 14.32 ± 4.01 and 12.46 ± 3.54 (NT); 0.04 ± 0.09 and 0.01 ± 0.04 (EP); 2.31 ± 2.60 and 1.91 ± 2.96 (CT); and 9.56 ± 3.77 and 8.79 ± 2.99 (NB). The results of the linear measurements (in mm) for TGr and CGr, respectively, were as follows: 3.85 ± 1.21 and 4.03 ± 0.94 (BH) and 10.91 ± 1.72 and 10.59 ± 1.80 (NC). There were no statistically significant differences between TGr and CGr for any measurement.

Conclusion: The early removal of ePTFE membranes in Class II furcation defects in dogs did not affect periodontal regeneration.
Human QKI, a new candidate gene for schizophrenia involved in myelination
Authors: Åberg Karolina , Saetre Peter , Lindholm Eva , Ekholm Birgit , Pettersson Ulf , Adolfsson Rolf , Jazin Elena
Published: December 2005

We have previously shown that chromosome 6q25–6q27 includes a susceptibility locus for schizophrenia in a large pedigree from northern Sweden. In this study, we fine‐mapped a 10.7 Mb region, included in this locus, using 42 microsatellites or SNP markers. We found a 0.5 Mb haplotype, likely to be inherited identical by decent, within the large family that is shared among the majority of the patients (69%). A gamete competition test of this haplotype in 176 unrelated nuclear families from the same geographical area as the large family showed association to schizophrenia (empirical P‐value 0.041). The only gene located in the region, the quaking homolog, KH domain RNA binding (mouse) (QKI), was investigated in human brain autopsies from 55 cases and 55 controls using a high‐resolution mRNA expression analysis. Relative mRNA expression levels of two QKI splice variants were clearly downregulated in schizophrenic patients (P‐value 0.0004 and 0.03, respectively). The function of QKI has not been studied in humans, but the mouse homolog is involved in neural development and myelination. In conclusion, we present evidence from three unrelated sample‐sets that propose the involvement of the QKI gene in schizophrenia. The two family based studies suggest that there may be functional variants of the QKI gene that increase the susceptibility of schizophrenia in northern Sweden, whereas the case‐control study suggest that splicing of the gene may be disturbed in schizophrenic patients from other geographical origins. Taken together, we propose QKI as a possible target for functional studies related to the role of myelination in schizophrenia. © 2005 Wiley‐Liss, Inc.
Genotypic interaction between DRD4 and DAT1 loci is a high risk factor for attention‐deficit/hyperactivity disorder in Chilean families
Authors: Carrasco Ximena , Rothhammer Paula , Moraga Mauricio , Henríquez Hugo , Chakraborty Ranajit , Aboitiz Francisco , Rothhammer Francisco
Published: December 2005

Attention‐deficit/hyperactivity disorder, ADHD [MIM 126452], is a common, highly heritable neurobiological disorder of childhood onset, characterized by hyperactivity, impulsiveness, and/or inattentiveness. As part of an ongoing study of ADHD, we carried out a family‐based discordant sib‐pair analysis to detect possible associations between dopamine receptor D4 (DRD4) and dopamine transporter 1 (DAT1) polymorphisms and ADHD in Chilean families. Both loci individually classified as homozygotes or heterozygotes for the DRD4 7‐repeat and DAT1 10‐repeat alleles, did not exhibit genotype frequency differences between affected children and their healthy siblings (Fisher's exact test P > 0.25 in both cases). However, the simultaneous presence of both DRD4 7‐repeat heterozygosity and DAT1 10 allele homozygosity were significantly higher (34.6%) in cases (26), compared with their unaffected siblings (25) (4%; Fisher's exact test P = 0.0096; odds‐ratio, OR = 12.71). Increased density of dopamine transporter in ADHD brains, along with abundance of 7‐repeat D4 receptors in prefrontal cortex, which is impaired in ADHD patients, make the observed gene–gene interaction worthy of further incisive studies. © 2005 Wiley‐Liss, Inc.
Synthesis and performance characteristics of a water‐based polyacrylate microemulsion for UHMWPE fiber adhesive coating
Authors: Lu Sheng‐Hua , Liang Guo‐Zheng , Wang Jie‐Liang , Ren Hui‐Jun
Published: December 2005

The water‐based polyacrylate microemulsion for ultrahigh molecular weight polyethylene (UHMWPE) fibers adhesive coating was synthesized by the emulsion polymerization of methyl methacrylate (MMA), butyl acrylate (BA), acrylic acid (AA), and hydroxyethyl acrylate (HEA) in the presence of a composite of sodium lauryl sulfate (SLS), OP‐10, and n‐octyl alcohol (NOA) as the emulsifier. The effects of the mass fraction of emulsifier and the reaction time on the properties of emulsion and its membrane were investigated. When m(BA) : m(MMA) : m(AA) : m(HEA) was 50 : 50 : 3 : 10 (wt ratio) and the mass fraction of emulsifier was 13 wt % and the reaction time was 3 h at 80°C, the latex particle diameter was 30 nm tested by transmission electron microscope (TEM). The Fourier transform infrared (FTIR) spectrometer and differential scanning calorimeter (DSC) were used to characterize the chemical structure and the glass transition temperature (Tg) of microemulsion membrane. The application results showed that this microemulsion was an ideal adhesive coating for UHMWPE fibers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Effects of silicon additive as synergists of Mg(OH)2on the flammability of ethylene vinyl acetate copolymer
Authors: Huang Honghai , Tian Ming , Liu Li , He Zhenhai , Chen Zhongqiang , Zhang Liqun
Published: December 2005

The present work dealt with the effects of nine kinds of silicon additives on flame retardancy of ethylene‐vinyl acetate copolymer (EVA)/magnesium hydroxide [Mg(OH)2] composites, as well as mechanical properties. The limiting oxygen index (LOI) test, horizontal fire test, vertical fire test, and cone calorimeter test were employed to evaluate flame retardancy of the composites. It was found that different silicon additives had different synergistic effects with Mg(OH)2on flame retardancy of the EVA matrix and exerted different influences on mechanical properties of the composites. The incorporation of organic montmorillonite (MMT) clay or silicone rubber not only made the composite reach FH‐1 rating in the horizontal fire test and FV‐1 rating in the vertical fire test, respectively, but also dramatically reduced the peak rate of heat release (Peak RHR) and increased the fire performance index (FPI) and ignition time (IT). The composites filled with precipitated SiO2exhibited the longest IT, the highest FPI, and FV‐1 rating. However, only the composites filled with silicone rubber could attain a balance between mechanical properties and flame retardancy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Effect of cryomilling on the thermal behaviors of poly(ethylene terephthalate)
Authors: Zhu Y. G. , Li Z. Q. , Zhang D. , Tanimoto T.
Published: December 2005

We have studied the effect of cryomilling (high‐energy ball milling under cryogenic temperature) on the thermal behaviors of poly(ethylene terephthalate) (PET) by comparing with original PET and quenched PET. Cryomilling induced the amorphization of crystalline PET, but the thermal behaviors of amorphous PET obtained from cryomilling are significantly different to those of amorphous PET obtained from quenching. Unlike amorphous PET obtained from quenching, the heating curve of amorphous PET obtained from cryomilling shows no cold crystallization peak, but evidences are found that its cold crystallization occurs within a wide temperature range. In addition, the stability of amorphous PET obtained from cryomilling is higher than that of amorphous PET obtained from quenching. The difference is proved to be attributed to the stored energy in cryomilled PET. The hot crystallization behaviors of PET improve a lot after cryomilling, and the heat stability of cryomilled PET is also better than those of original PET during reheating. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Surface characterization of low‐temperature cascade arc plasma–treated low‐density polyethylene using contact angle measurements
Authors: Gilliam M. A. , Yu Q. S.
Published: December 2005

Low‐density polyethylene (LDPE) was treated with a low‐temperature cascade arc plasma torch (LTCAT) of argon with or without adding a reactive gas of oxygen or water vapor. The static sessile droplet method and the dynamic Wilhelmy balance method were employed to perform surface contact angle measurement in order to investigate and characterize the effects of LTCAT treatment on LDPE surfaces. These treatment effects included changes in surface wettability and surface stability and possible surface damage that would create low‐molecular‐weight oligomers on the treated surface. Experimental results indicated that the combination of static and dynamic surface contact angle measurements enabled a comprehensive investigation of these effects of plasma treatment on a polymer surface. Without the addition of a reactive gas, a 2‐s argon LTCAT treatment of LDPE resulted in a stable hydrophilic surface (with a water contact angle of 40°) and little surface damage. The addition of oxygen into argon LTCAT produced a less stable LDPE surface and showed more surface damage. Adding H2O vapor into argon LTCAT produced an extremely hydrophilic surface (with a water contact angle < 20°) of LDPE but with pronounced surface damage. When compared with conventional radio frequency (13.56 MHz) plasmas, LTCAT treatment provides a much more rapid, effective, and efficient method of surface modification of LDPE. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2528–2541, 2006
Effect of ultrasound on wettability between aramid fibers and epoxy resin
Authors: Liu L. , Huang Y. D. , Zhang Z. Q. , Yang X. B.
Published: December 2005

Good wetting of reinforced fiber by resin was a main factor in the improvement of the interface adhesion of their composites. Ultrasound with a frequency of 20 kHz was used to improve the wettability between aramid fibers and epoxy resin during the winding process of the composites. The effects of ultrasound on the viscosity and surface tension of epoxy resin and on the surface characteristics of aramid fibers were investigated. The wettability of aramid fibers and treated epoxy resin under different conditions and of aramid fibers and epoxy resin under ultrasonic online treatment were compared. The results indicated that the main action of ultrasound was to force epoxy resin to impregnate aramid fibers, in addition to the influence of ultrasound on the properties of epoxy resin and aramid fibers. The results of microdebond testing showed that the interfacial shear strength (IFSS) of aramid/epoxy composites could be 26% higher than that of untreated composites because of the improved wettability between aramid fibers and epoxy resin subjected to ultrasonic online treatment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Interpenetrating polymer networks based on nitrile rubber and metal methacrylates
Authors: Samui A. B. , Dalvi V. G. , Chandrasekhar L. , Patri M. , Chakraborty B.C.
Published: December 2005

Interpenetrating polymer networks (IPNs) based on nitrile rubber (NBR) as first component and zinc dimethacrylate (ZnDMA), aluminum trimethacrylate (AlTMA), or zirconium tetramethacrylates (ZrTeMA) as second component were synthesized. Sequential IPNs (SeqIPN) were formed by two routes such as compression molding (CM) and swelling/curing (SC). The IPNs were found to have superior properties compared to metal oxide/hydroxide‐filled NBR. Tensile strength has increased to a large extent while maintaining appreciable elongation. Total crosslink density (covalent and ionic) was found to increase in the order NBR/metal oxide or hydroxide < SeqIPN(CM route) < SeqIPN (SC route). IPNs are found to retain high storage modulus even in the rubbery region. It is observed that change of technique for IPN formation has drastically changed the modulus of the present system. Decrease in tan δ value and inward shifting of peaks were observed because of IPN formation. Morphology of SeqIPN by SC process was found to be more uniform compared to others. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2542–2548, 2006
Morphology of pyrolysed polystyrene–isoprene–styrene and polystyrene–butadiene–styrene block copolymers
Authors: Sarwade B. D. , Sanghavi R. R. , Sarwade D. B. , Asthana S. N.
Published: December 2005

The surface morphology of thermooxidative degraded polystyrene–isoprene–styrene (SIS) and polystyrene–butadiene–styrene (SBS) thermoplastic block copolymers was studied by scanning electron microscopy. Surface changes caused by heating the samples in a pyrolyzer for 15 and 30 min were presented in different micrographs. The morphological changes occurring due to the formation of polar groups and their crosslinking during the thermooxidative degradation are discussed. Morphological study of these thermally degraded polymer samples shows very good correlation with the thermodegradation results. The rate of thermodegradation is fast in case of SBS when compared with SIS block copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2549–2553, 2006
SEM studies of surfactant‐assisted micro‐mixing of melamine and wax particles
Authors: Karakatsanis Ekaterini , Focke Walter W. , Summers Gabriel J.
Published: December 2005

The validity of the micro‐mixing phenomenon was investigated by mixing a melamine dispersion, stabilized by low molecular mass poly(acrylic acid) (∼5000 Daltons) and a wax emulsion, stabilized by an ethoxylated alkyl phenol surfactant. The wax particles were observed to be attached to the melamine surface because of the interaction between the poly(acrylic acid) dispersant and the ethoxylate group of the wax surfactant, resulting in the sedimentation of mixed particles. This phenomenon has potential application in the mixing of solid particles that require intimate contact and homogeneous mixing. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2554–2557, 2006
Morphology of pyrolyzed polystyrene–isoprene–styrene and polystyrene–butadiene–styrene block copolymers
Authors: Sarwade B. D. , Sanghavi R. R. , Sarwade D. B. , Asthana S. N.
Published: December 2005

The surface morphology of thermooxidative‐degraded polystyrene–isoprene–styrene (SIS) and polystyrene–butadiene–styrene (SBS) thermoplastic block copolymers were studied by scanning electron microscopy. Surface changes caused by heating the samples in a pyrolizer for 15 and 30 min were presented in different micrographs. The morphological changes occurring due to the formation of polar groups and their crossing linking during the thermooxidative degradation are discussed. Morphological study of these thermally degraded polymer samples show very good correlation with the thermodegradation results. The rate of thermodegradation is fast in case of SBS compared with SIS block copolymer. ©2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Polypropylene–clay blends compatibilized with MAH‐g‐POE
Authors: Zhong Weixia , Qiao Xiuying , Sun Kang , Zhang Guoding , Chen Xiaodong
Published: December 2005

A series of new Polypropylene (PP)–clay blends, containing 5 wt % clay, were prepared by melt compounding with maleic anhydride grafted poly(ethylene‐co‐octene) (MAH‐g‐POE) as the compatibilizer by varying its content from 0 to 20 wt %. The effect of MAH‐g‐POE on the PP–clay miscibility was examined by X‐ray diffraction (XRD), scanning electronic microscope (SEM) observation, differential scanning calorimeter (DSC) analysis, dynamic mechanical thermal analysis (DMTA), and rheological testing in sequence. The results showed that the addition of MAH‐g‐POE could improve the dispersion of clay layers in PP matrix and promoted the interaction between PP molecules and clay layers. At 10 wt % MAH‐g‐POE, the PP–clay blend exhibited a highest value of Tc,onset and Tg as well as a biggest melt storage modulus (G′), indicating the greatest PP–clay interaction. On the other hand, improved toughness and stiffness coexisted in blends with 5–10 wt % loading of MAH‐g‐POE. In view of SEM and DMTA observations, MAH‐g‐POE was well miscible with the PP matrix, even with the concentration up to 20 wt %. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2558–2564, 2006
Effects of activation time on the properties and structure of polyacrylonitrile‐based activated carbon hollow fiber
Authors: Sun Junfen , Wang Xiaqin , Wang Chaosheng , Wang Qingrui
Published: December 2005

Polyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate, then further oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of activation time of a precursor fiber on the microstructure, specific surface area, pore‐size distribution, and adsorption properties of PAN‐based activated carbon hollow fibers (PAN‐ACHF) were studied in this work. The BET surface area of PAN‐ACHF and surface area of mesopores gradually increase with activation time extending, and reach the maximum values, 780 and 180 m2 g−1, respectively, when fibers are activated at 800°C for 100 min. The adsorption ratio to creatinine changes little with activation time extending and all values over all activation time are above 90%. The adsorption ratio to VB12 gradually increases with activation time extending before 60 min, and then becomes relatively constant from 60 to 100 min. The number of pores on the surface of PAN‐ACHF increases with activation time extending. The amount of mesopores in PAN‐ACHF made of fibers activated for different time increases with activation time extending and the dominant pore sizes of mesopores in PAN‐ACHF range from 2 to 5 nm. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2565–2569, 2006
Performance of natural‐fiber–plastic composites under stress for outdoor applications: Effect of moisture, temperature, and ultraviolet light exposure
Authors: Lopez J. L. , Sain M. , Cooper P.
Published: December 2005

The effects of moisture, temperature, and ultraviolet (UV) light on performance of natural‐fiber–plastic composites (NFPC) were assessed. We conducted short‐term tests in the laboratory and long‐term tests under natural exposure and measured changes in mechanical properties and color in samples of the composite. Chemical changes of the composite's materials were measured by X‐ray photoelectron spectroscopy to elucidate the mechanisms of chemical transformations on the material surface. Relative humidity highly affected the modulus of rupture (MOR) and the modulus of elasticity (MOE), and had a greater effect than temperature and UV exposure on performance of the composite. The lightness of the composite was increased by the UV effect in the short‐ and the long‐term tests. The X‐ray photoelectron spectroscopy (XPS) analysis suggested that the composite was protected by the UV absorber. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2570–2577, 2006
Novel preparation and properties of EPDM/montmorillonite nanocomposites
Authors: Liu BaoLei , Ding QingJun , He QiHui , Cai Jun , Hu BaiXing , Shen Jian
Published: December 2005

This article reports on a novel route to develop ethylene–propylene–diene rubber (EPDM)/montmorillonite nanocomposites Modification of the MMT was carried out with maleic anhydride (MA), which acts as the intercalation agent for MMT and the vulcanizing agent for EPDM matrix, as well as the compatibilizer for the EPDM and MMT phases. The effect of MA‐modified MMT in nanocomposites was investigated by focusing on three major aspects: structural analysis, thermal properties, and material properties. The d‐spacings of both the MA modified MMT and exfoliated nanocomposites were investigated by X‐ray diffraction (XRD), and the morphology of these nanocomposites was examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Dynamic mechanical analysis confirms the constraint effect of exfoliated MMT layers on EPDM chains, which benefited the increased storage modulus, increased glass transition temperature. Thermogravimetric analysis indicates that there is some enhancement in degradation behavior between the nanocomposites and EPDM matrix. The nanocomposites exhibit great improvement in tensile strength and modulus, as well as elongation‐at‐break. The effects of MA addition on the formation of nano‐metric reinforcement and on the mechanical properties of nanocomposites are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2578–2585, 2006
One‐step synthesis of bis‐macromonomers of poly(1,3‐dioxolane) catalyzed by Maghnite‐H+
Authors: Reguieg Fatiha , Sahli Nabahat , Belbachir Mohamed , Lutz Pierre J.
Published: December 2005

Telechelic poly(1,3‐dioxolane) (PDXL) bis‐macromonomers bearing methyl methacrylate end groups were prepared by cationic ring‐opening polymerization of 1,3‐dioxolane (DXL), in the presence of methacrylic anhydride, catalyzed by Maghnite‐H+ (Mag‐H+), in bulk and in solution. Maghnite is a montmorillonite sheet silicate clay, which exchanged with protons to produce Mag‐H+. The influence of the amount of Mag‐H+, monomer (DXL), and methacrylic anhydride on monomer conversion was studied. The polymerization yield and the molecular weight of α,ω‐bis‐unsaturated PDXLs prepared depend on the amount of Mag‐H+ used and the reaction time. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Characteristics of polystyrene/organoclay nanocomposites prepared by in‐situ polymerization with macroazoinitiator containing poly(dimethylsiloxane) segment
Authors: Jeong Han Mo , Choi Ji Suk , Ahn Young Tae , Kwon Kun Ho
Published: December 2005

Polystyrene (PS)/organoclay nanocomposites were prepared by the in situ polymerization of styrene in the presence of organoclay with macroazoinitiator (MAI), composed of repeated sequences of poly(dimethylsiloxane) (PDMS) and azo groups. The X‐ray diffraction patterns and the morphology observed with a transmission electron microscope showed that the dispersion of organoclay in polymer matrix improved as the content of the PDMS segment in the nanocomposite increased. However, negative effects on the rise of glass transition temperatures and the thermal resistance of nanocomposite, measured by differential scanning calorimetry and thermogravimetry, at a high content of the PDMS segment, suggested that organoclay lay preferentially in the PDMS domain. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2841–2847, 2006
Alkaline treatment of cotton in different reagent mixtures with reduced water content. I. Influence of alkali type and additives
Authors: Ibanescu Constanta , Schimper Christian , Bechtold Thomas
Published: December 2005

The purpose of this study was to examine the influence of some swelling agents with reduced water content on final properties of cotton fabrics. A single‐step swelling of cotton in the reagent was used. There were selected properties generally used to characterize mercerized cotton that are technologically important, such as water retention, shrinkage, stiffness, crease recovery angle, and hand. Water retention method and dyeing with CI Direct Red 81 have been used to compare the degree of swelling for different samples. Correlations have been established between structural changes induced by the swelling agents and final properties of cotton fabric. The mixtures of an alkali solution and an additive produced similar or better end‐use properties as compared with classical sodium hydroxide or ammonia treatments, combining the action of a diluted alkali solution (3.13 mol/L NaOH or KOH) and a nonalkali reagent. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2848–2855, 2006
Controlled release and absorption of cetylpyridinium chloride using polymer hydrogels
Authors: Densmore Crystal G. , Robison Thomas W. , Smith Barbara F. , Lewis Randall E.
Published: December 2005

Interest in the biocide cetylpyridinium chloride (CPC) has resurged based on new studies showing its effectiveness against a wide variety of pathogens. Hydroxyethyl methacrylate (HEMA)‐based hydrogels have been developed for the controlled release of CPC. Initial burst release of the biocide can be controlled and sustained release can be achieved for more than two weeks. The burst and sustained release can be adjusted by varying the amount of anionic monomer (AMPSA), crosslink content (DEGDMA), release media, hydrogel surface area, and CPC loading. After removing the CPC‐loaded hydrogel from solution and drying, the release of CPC can also be reactivated. Very interesting swelling behavior was observed for CPC‐loaded hydrogels due to the electrostatic and hydrophobic interactions between the polymer hydrogel and CPC. In addition, HEMA‐based hydrogels can be used to recover or absorb CPC from aqueous solutions. By increasing the amount of AMPSA in the HEMA‐based hydrogel, more CPC can be absorbed from solution. The absorption is also enhanced by agitating the solution. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006
Gebäudeplanung in der Nähe von Schienenverkehrswegen – Meßtechnische Untersuchungen – Prognosen – Beurteilungen – Schutzmaßnahmen
Authors: Lenz Udo
Published: December 2005

In innerstädtischen Bereichen sind Neubauten häufig vor Schwingungsimmissionen von Schienenverkehrswegen zu schützen. Auf der Basis von meßtechnischen Untersuchungen läßt sich anhand des vom Bauherrn definierten Schutzanspruchs eine Aussage über die Notwendigkeit von Maßnahmen treffen. Schutzmaßnahmen können direkt am Gleis durch Variation des Oberbaus getroffen werden. Es besteht die Möglichkeit der Beeinflussung der Immissionen auf den Ausbreitungsweg zwischen Gleisanlage und Gebäude. Im Gebäude selbst lassen sich auch Maßnahmen zur Schwingungsreduzierung vorsehen.
Berechnung von Baugrubenwänden mit verschiedenen Methoden: Trägermodell, nichtlineare Bettung, Finite‐Elemente‐Methode
Authors: Hettler Achim , Ortiz Susana Vega , Mumme Britta
Published: December 2005

Am Beispiel einer einfach gestützten Wand in mitteldicht gelagertem Sand werden drei verschiedene Berechungsmethoden miteinander verglichen: Trägermodell mit unverschieblichen Auflagern, Trägermodell mit nichtlinearer Bettung nach Besler und Finite‐Elemente‐Methode mit der Hypoplastizität bzw. mit der durch intergranulare Dehnung erweiterten Hypoplastizität. Die Untersuchungen beinhalten schwerpunktmäßig Schnittgrößen und Wandverformungen und die Art der Einbindung des Wandfußes. Am Schluß werden die wesentlichen Ergebnisse zusammengefaßt und Empfehlungen für die praktische Anwendung gegeben.