bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dissolution of softwood kraft pulps by direct derivatization in lithium chloride/N,N‐dimethylacetamide
Authors: Berthold Fredrik , Gustafsson Kristina , Berggren Rickard , Sjöholm Elisabeth , Lindström Mikael 
Published: August 2004

AbstractA method for the characterization of the molar mass distributions (MMDs) of softwood kraft pulps dissolved in 0.5% lithium chloride (LiCl)/N,N‐dimethylacetamide (DMAc) by size exclusion chromatography is presented. The method is based on derivatization with ethyl isocyanate and the dissolution of samples in 8% LiCl/DMAc. In this study, the derivatization of hardwood kraft pulps did not influence the MMD. In the case of softwood pulps, however, the derivatization decreased the proportion of the high‐molecular‐mass material and increased the proportion of the low‐molecular‐mass material, which resulted in a distribution similar to the MMD of a hardwood kraft pulp. The results suggest that associations between hemicellulose and cellulose in the softwood kraft pulp were ruptured during derivatization. This led to a more correct estimation of the MMD of derivatized softwood kraft pulps than obtained by the dissolution of nonderivatized samples. This new method offers several advantages over derivatization with phenyl isocyanate: a precipitation step is not necessary, it is possible to follow the lignin distribution in the samples, and the method allows very high levels of dissolution of softwood kraft pulps up to a κ number of around 50. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 424–431, 2004
Miscibility studies on poly(ethylene glycol)/dextran blends in aqueous solutions by dilute solution viscometry
Authors: Kavlak Serap , Can Hatice Kaplan , Güner Ali 
Published: August 2004

AbstractMiscibility of poly(ethylene glycol) (PEG) with dextran (Dx) was investigated by dilute solution viscometry. Dilute solution viscosity measurements were made on ternary systems, polymer (1)/polymer (2)/solvent (H2O), for four different average molecular weights of PEG and Dx. The intrinsic viscosity and viscometric interaction parameters were experimentally measured for the binary (solvent/polymer) as well as for the ternary systems by classical Huggins equation. Degree of miscibility of these polymer systems was estimated on the basis of the four following criteria: (1) the sign of the ΔkAB, (2) the sign of α, (3) the sign of ΔB, and (4) the sign of the μ. Based on the sign convention involved in these criteria, immiscibility was observed in most systems. The miscibility of all these systems in accordance with the interactions between the unlike polymer chains rather the polymer–solvent interactions were investigated depending on molecular weight of polymer sample. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 453–460, 2004
Pervaporation properties of humic acid–added membranes
Authors: Mishima S. , Nakagawa T. 
Published: August 2004

AbstractThe saving and recycling of chemical substances, which may be hazardous to human health and ecosystems, constitute a desirable goal worldwide. It is important to use a natural polymer that has a highly specific function and an environmental friendliness. In this study, humic acid was added to a natural polymer, a pectin membrane, and a hydrophobic poly(1‐trimethylsilyl‐1‐propyne) (PMSP) membrane to enhance the affinity for phenol or aniline. Also, the separation performance, based on the membrane materials and methods of addition, was investigated. The effect of the adsorption of phenol and aniline by humic acid was investigated. A high rate of aniline adsorption was observed. The interaction of the humic acids and the aniline was mainly observed by polar bonding. For the PMSP membrane with humic acid added to the surface, the humic acid exists in a colloidal state. During pervaporation, the permeation of water was prevented by the adsorbed solute. Because the permeability of aniline increased and the permeability of water significantly decreased, the PMSP membrane with humic acid added to the surface had a high permeate aniline concentration, and the permselectivity was improved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 461–468, 2004
Simplified theory for linear rheology of monodisperse linear polymers
Authors: Heuzey Marie‐Claude , Wood‐Adams Paula , Sekki Djamila 
Published: August 2004

AbstractA new version of the tube theory based on the de Gennes–Doi–Edwards reptation concept (reported in Likhtman and McLeish's work published in 2002) is evaluated, modified to allow for simplified computations, and used to study the relationship between zero‐shear viscosity and molecular weight for monodisperse entangled linear homopolymers. The Likhtman–McLeish model combines self‐consistent theories for contour length fluctuations and constraint release with reptation theory for monodisperse linear polymers. Because of the nature of the Rubinstein and Colby approach used for the treatment of constraint release, the related term is probabilistic and requires stochastic simulations for the calculation of the relaxation modulus G(t). This makes the Likhtman–McLeish model computationally difficult to use. In this work we solve this problem by generating an approximate closed‐form solution for the stochastic term. Then analytical integration of the relaxation modulus function G(t) provides an expression for the zero‐shear viscosity (η0). Results of the computations of the zero‐shear viscosity and of the slope of η0 versus molecular weight are compared with available experimental data for monodisperse entangled linear polystyrene and polyethylene (hydrogenated polybutadiene). The model is a major improvement over previous theoretical models, even if there is still some disagreement between the predictions and experimental data of the slope of η0 versus molecular weight. The possibility of inferring monomer chemistry–dependent parameters from the zero‐shear viscosity remains a difficult task because of the introduction of a constraint‐release parameter. Nevertheless, the model is a useful tool for the prediction of linear viscoelasticity data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 569–586, 2004
Effects of diluent's concentration upon the properties of organically modified ceramics based composites for application in dentistry
Authors: Lizymol P. P. 
Published: August 2004

AbstractOrganically modified ceramic resin (ormoresin) mixed with triethylene glycol dimethacrylate (TEGDMA) was used as the binder resin for the preparation of visible light cured dental composite. Three different combinations of ormoresin and TEGDMA were used for the preparation of composites, and their properties were compared in terms of depth of cure, diametral tensile strength (DTS), flexural strength (FS), flexural modulus (FM), Vickers micro hardness (VMH), water sorption (WS), and solubility. It is found that an optimum amount of diluent is necessary for better crosslinking and properties of cured composites based on ormoresin. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 469–473, 2004
Sorption and diffusion of supercritical carbon dioxide into polysulfone
Authors: Tang Muoi , Huang Yi‐Ching , Chen Yan‐Ping 
Published: August 2004

AbstractSorption and diffusion of supercritical carbon dioxide (SCCO2) into polysulfone (PSF) from 313 K and 20 MPa to 333 K and 40 MPa were investigated in this study. A simple gravimetric method was used to measure the mass gain of SCCO2 in PSF, and the Fick's diffusion model was applied to describe the desorption process. The sorption amount, the sorption diffusivity under supercritical states, and the desorption diffusivity at ambient conditions are presented. Comparisons of the sorption amounts and diffusivities of CO2 for polymers of polycarbonate and PSF are discussed according to the interactions between gas and polymers. The morphology change and plasticization effect attributed to gas sorption in PSF were studied. Effects of glass‐transition temperature and yielding stress for PSF and other polymers were used to describe the difference in their diffusivities for the sorption and desorption processes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 474–482, 2004
Reverse temperature injection molding of Biopol™ and effect on its properties
Authors: Zhang Jinwen , McCarthy Stephen , Whitehouse Robert 
Published: August 2004

AbstractA novel reverse temperature profile for the injection molding of Biopol™ was studied. It was found that both the mechanical properties and the part quality of Biopol™ were improved with this new reverse temperature process. When injection molded, most conventional thermoplastic polymers are processed at 30 to 70°C above the melting temperature; under these conditions, Biopol™ degraded rapidly and the resulting material showed poor mechanical properties. In contrast, when using a reverse temperature molding process, where Biopol™ was melted in the first zone and then was conveyed through the barrel with a decreasing temperature pathway and was injection‐molded at a temperature below its melting point, the resulting material showed higher mechanical properties. The processing of Biopol™ was also greatly improved. The reverse temperature process uses the characteristically slow crystallization rate of Biopol™, which can be easily injected as hot melt even below its normal melting point. DSC analysis suggested that the reverse temperature process resulted in a more homogeneous crystalline phase than the conventional process. GPC analysis also indicated that thermal degradation of Biopol™ was largely reduced in the reverse temperature injection‐molding process compared with conventional methods. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 483–491, 2004
Effects of water contents and postcuring conditions on Bis‐GMA/TEGDMA dental restorative composite resins
Authors: Fong Hao 
Published: August 2004

AbstractDental restorative composite resins of the monomer bisphenol A glycerolate dimethacrylate (Bis‐GMA/TEGDMA; 50/50, mass ratio), with different initial water contents in monomer mixtures and subject to various postcuring conditions, were prepared. The effects of water contents and postcuring conditions on photopolymerization rate, degree of methacrylate double bond conversion, and mechanical properties (flexural strength and elastic modulus) were systematically investigated. Within the scope of this investigation, the initial water content was not found to significantly affect the mechanical properties of the photocured composite resins. Nevertheless, the addition of distilled water into the monomer mixture slightly increased the degree of methacrylate double bond conversion, and slightly slowed down the photocuring process, especially when the amount of water was oversaturated. Postcuring conditions of 37°C vapor or water aging increased the degree of methacrylate double bond conversion, but made the mechanical properties of the composite resins less desirable, especially under water‐aging conditions. Postcuring treatment of the composite resins in a 100°C vacuum (∼ 27.9 KPa) oven for 1 day improved both the flexural strength and the elastic modulus by at least 30%, but the improvements quickly diminished upon subsequent 37°C water aging. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 492–502, 2004
Ageing studies of pineapple leaf fiber–reinforced polyester composites
Authors: Uma Devi L. , Joseph Kuruvila , Manikandan Nair K. C. , Thomas Sabu 
Published: August 2004

AbstractThis experimental study evaluated the water absorption characteristics of pineapple leaf fiber (PALF)–polyester composites of different fiber content. The degree of water absorption was found to increase with fiber loading. The mechanism of diffusion was analyzed and the effect of fiber loading on the sorption kinetics was studied. The diffusion coefficient was calculated and found to increase with fiber content. Studies were also made to correlate water absorption with the cross‐sectional areas of the specimens. The effects of ageing on the tensile properties and dimensional stability of PALF polyester composites were studied under two different ageing conditions. Ageing studies showed a decrease in tensile strength of the composites. The composite specimens subjected to thermal ageing showed only a slight deterioration in strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 503–510, 2004
Synthesis and application of multilayered core shell particles for toughening of unsaturated polyester resin
Authors: Guhanathan S. , Saroja Devi M. 
Published: August 2004

AbstractToughening particles, comprising two radially alternating rubbery and glassy layers, were prepared by using sequential emulsion polymerization. The conditions which led to controlled particle size and morphology are discussed. A relatively new type of inert core shell particle [fly‐ash (FA)] and surface‐activated FA, by two different silane coupling agents, namely 3‐aminopropyltrimethoxy silane (AMP) and vinyltriethoxysilane (VES)‐based multilayered toughening particles, which radially comprise rubbery and glassy layers, were also prepared. The toughening particles were used with general purpose polyester resin (GPR) for making composite sheets. Formation of multiple layers in the core‐shell particles and their morphology were confirmed by transmission electron microscopy (TEM). The mechanical properties such as tensile, flexural, impact, and hardness of the toughened GPR are discussed critically. The tensile fractured surfaces were studied by scanning electron microscopy (SEM). Thermal property such as thermogravimetric analysis (TGA) were also discussed. The composites were exposed to various adverse environmental conditions such as water, boiling water, salt water, acid, alkali, toluene, weather, and freezing–thawing for 30 days. The mechanical properties (viz. the tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus, impact strength and hardness of FA/GPR, FA.AMP core/GPR, and FA.VEScore/GPR) were studied before and after exposure to adverse environmental conditions. The results indicate that the mechanical properties of FA/GPR composite are improved by surface treatment of FA and their resistance to the various environmental stresses is also enhanced substantially on modification by toughening particles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 511–528, 2004
Modification of the polarity of isotactic polypropylene through blending with oxidized paraffin wax
Authors: Novák I. , Krupa I. , Luyt A. S. 
Published: August 2004

AbstractThe modification of the polarity of isotactic polypropylene (iPP) through blending with oxidized paraffin wax (Fischer–Tropsch synthesis) was investigated. The oxidized paraffin wax significantly increased the polar component of the total surface free energy of polypropylene. Modified iPP also showed significantly higher adhesion to the polar substrate, as represented by a crosslinked epoxy‐based resin. The conservation of the good mechanical properties of the blends was observed up to 6 wt % wax. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 529–533, 2004
Novel polyether polyurethane/clay nanocomposites synthesized with organic‐modified montmorillonite as chain extenders
Authors: Ni Ping , Li Jing , Suo Jishuan , Li Shuben 
Published: August 2004

AbstractA novel polyether polyurethane/clay nanocomposite was synthesized using polytetramethyleneglycol (PTMEG), 4,4′‐diphenylmethane diisocyanate (MDI), 1,6‐hexamethylenediamine, and modified Na+‐montmorillonite. Here, organic‐modified montmorillonite (O‐MMT) was formed by applying 1,6‐hexamethylenediamine as a swelling agent to treat Na+‐montmorillonite. The X‐ray analysis showed that exfoliation occurred for the higher O‐MMT content (40 wt %) in the polymer matrix. Mechanical analysis indicated that when the O‐MMT was used as chain extender to replace a part of 1,2‐diaminopropane to form PU/clay nanocomposites, the strength and strain‐at‐break of the polymer were enhanced with increased content of O‐MMT in the matrix. When the O‐MMT content attained about 5%, the tensile strength and elongation at break were over two times that of the pure PU. The thermal stability and the glass‐transition of O‐MMT/PU nanocomposites also increased with increasing the O‐MMT content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 534–541, 2004
Fetal toxicity of valsartan and possible reversible adverse side effects
Authors: Berkane Nadia , Carlier Patrick , Verstraete Lieve , Mathieu Emmanuelle , Heim Nazbanou , Uzan Serge 
Published: August 2004

AbstractBACKGROUNDPublished cases suggest that the use of angiotensin II receptor antagonists is fetotoxic during the third trimester, but not in early pregnancy. CASE: We report a case in which the adverse fetal effect of angiotensin II receptor antagonist treatment was reversed. A woman with chronic hypertension was treated with valsartan until gestation week (GW) 20, when a complete anhydramnios was observed. Six days after interruption of the treatment, amniotic fluid reappeared. It reached a normal level at GW 23.5. The plasmatic creatinine level and the renal ultrasound examination were within normal limits at the six‐month follow‐up.CONCLUSIONSWhereas angiotensin‐II‐receptor antagonist generates a severe renal toxicity, this case suggests that, at least in the first half of pregnancy, these effects can be reversed. Birth Defects Research (Part A) 67:, 2004. © 2004 Wiley‐Liss, Inc.
Anomalies of the forebrain with radial limb defects: Garcia‐Lurie‐Steinfeld syndrome?
Authors: McPherson Elizabeth , Huff Dale , Dunn Jeanette , Muenke Maximilian 
Published: August 2004

AbstractBACKGROUNDSevere anomalies of the forebrain together with radial limb anomalies have been reported in Steinfeld syndrome, XK aprosencephaly, and partial monosomy 13q. Steinfeld syndrome is an extremely variable autosomal dominant condition that, in severe cases, is characterized by holoprosencephaly, radial limb defects, and renal and/or cardiac defects. In mild cases there may be only thumb hypoplasia, ocular coloboma, or oral clefts. XK aprosencephaly, also called Garcia‐Lurie syndrome (GLS), is a usually sporadic disorder with radial limb defects and aprosencephaly/atelencephaly. Based on two atypical sibships, autosomal recessive inheritance has been suggested. Two patients with variations of monosomy 13q have been described with atelencephaly but, generally, Steinfeld and XK aprosencephaly patients are chromosomally normal. Holoprosencephaly in 13q deletion patients appears to be due to ZIC2 mutations, but ZIC2 has not been previously tested in Steinfeld syndrome or GLS patients.CASESWe report three sporadic cases with clinical features intermediate between Steinfeld and GLS, including severe forebrain malformations and radial limb defects. All had normal karyotypes, and mutations in ZIC2 were absent in the two cases tested.CONCLUSIONSIn our cases and in the literature there is significant clinical overlap between Steinfeld syndrome and GLS. We propose these conditions may not be nosologically or etiologically distinct. The spectrum of severe forebrain anomalies in these conditions is broader than previously thought and may include some neural tube defects. Mild cases are difficult to identify and the full range of expression remains unknown. Autosomal dominant inheritance with incomplete penetrance and frequent new mutations is postulated. Thorough clinical evaluation is recommended for children with severe forebrain and radial limb defects. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Heterogeneous Oxidation of Pyrimidine and Alkyl Thioethers in Ionic Liquids over Mesoporous Ti or Ti/Ge Catalysts
Authors: Cimpeanu Valentin , Parvulescu Vasile I. , Amorós Pedro , Beltrán Daniel , Thompson Jillian M. , Hardacre Christopher 
Published: August 2004

AbstractHeterogeneous catalytic oxidation of a series of thioethers (2‐thiomethylpyrimidine, 2‐thiomethyl‐4,6‐dimethyl‐pyrimidine, 2‐thiobenzylpyrimidine, 2‐thiobenzyl‐4,6‐dimethylpyrimidine, thioanisole, and n‐heptyl methyl sulfide) was performed in ionic liquids by using MCM‐41 and UVM‐type mesoporous catalysts containing Ti, or Ti and Ge. A range of triflate, tetrafluoroborate, trifluoroacetate, lactate and bis(trifluoromethanesulfonyl)imide‐based ionic liquids were used. The oxidations were carried out by using anhydrous hydrogen peroxide or the urea–hydrogen peroxide adduct and showed that ionic liquids are very effective solvents, achieving greater reactivity and selectivity than reactions performed in dioxane. The effects of halide and acid impurities on the reactions were also investigated. Recycling experiments on catalysts were carried out in order to evaluate Ti leaching and its effect on activity and selectivity.
Ductoscopic cytology and image analysis to detect breast carcinoma
Authors: Sauter Edward R. , Klein‐Szanto Andres , Ehya Hormoz , MacGibbon Brenda 
Published: August 2004

AbstractBACKGROUNDThe goal of the prospective study was to determine whether 1) image analysis (IA; including DNA index [DI], S‐phase fraction, and the presence or absence of aneuploidy or hypertetraploidy [HT]) of fiberoptic ductoscopy (FD) breast specimens was feasible, 2) IA findings from FD specimens predicted histopathologic evidence of disease, and 3) a combination of IA, cytology, and clinical factors provided complementary information in the diagnosis of breast carcinoma.METHODSIA and cytologic evaluation were performed on 106 consecutively collected ductoscopic specimens from 88 subjects.RESULTSIA was successful in 73 (71%) FD specimens. HT (P = 0.03) was related to intraductal visual observations. The proportion of atypical papillomas with aneuploidy was greater (P = 0.05) than in any other class. The HT index was higher in atypical papilloma (P = 0.02) and in breast carcinoma (P = 0.05) than with other diagnoses. The proportion of papilloma cases with HT was greater (P = 0.04) than benign papillomas. Malignant cytology was associated with a higher DI (P = 0.02) and a higher HT index (P = 0.001) than nonmalignant (benign or atypical) cytology. HT (P = 0.002) was less common with cytology containing few epithelial cells, and the HT index was higher with malignant versus nonmalignant FD cytology (P = 0.001). The percentage of cells containing HT was greater in FD specimens that were suspicious for malignancy (P = 0.006) than in those with benign cytology or mild atypia. Considering all samples and combining IA, cytologic, and visual findings in a stepwise linear discriminant analysis optimized the sensitivity (61%) and specificity (90%) of breast carcinoma prediction. Excluding spontaneous nipple discharge (SND) samples and adding epithelial cell quantity in samples improved the model (sensitivity, 85%; specificity, 80%).CONCLUSIONSIA was feasible in FD specimens whenever adequate epithelial cells were present. IA and cytologic findings were associated. Adding IA results to cytology and visual findings and excluding samples with SND improved diagnostic sensitivity. Cancer 2004. © 2004 American Cancer Society.