bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonisothermal crystallization of reprocessed poly(ethylene terephthalate)
Authors: Spinacé M. A. Silva , De Paoli M.‐A. 
Published: November 2003

AbstractPoly(ethylene terephthalate) was submitted to five reprocessing cycles by extrusion. The materials were analyzed with oligomer and after oligomer extraction. The nonisothermal crystallization of the five samples was investigated by differential scanning calorimetry. Samples with oligomer content and carboxylic end group concentrations between 44 and 98 eqw × 106 g presented a nonlinear correlation with the crystallization temperature. After the oligomer extraction of the polymer, this correlation is linear. The nonisothermal crystallization results were analyzed using the Ozawa model. The polymers containing oligomers obey the Ozawa model for the first reprocessing cycle. After oligomer extraction, the polymers obey the Ozawa model from the first to the third reprocessing cycle. In both cases, the exponential n values are close to 2.0. For the other cycles, deviations from this model occur. The activation energy was calculated using the Kissinger and Varma models. The values obtained for the five reprocessed samples were inversely proportional to the molar mass when analyzed by both models. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 525–531, 2004
Effects of crosslinking agents, dyeing temperature, and pH on mechanical performance and whiteness of silk fabric
Authors: Leksophee T. , Supansomboon S. , Sombatsompop N. 
Published: November 2003

AbstractThe effects of bleaching and dyeing conditions on abrasion resistance, tear strength, and whiteness of silk fabrics were studied. Different crosslinking agents at various concentrations were introduced into the silk fabrics under various dyeing temperatures and pH. The results indicated that the oxidatively bleached silk fabric exhibited better mechanical properties than those of reductively bleached silk fabric. Sodium citrate was found to be the most suitable crosslinking agent for enhancing the abrasion resistance and tear strength of the silk fabrics with no significant effect on the whiteness. The mechanical property improvements of sodium citrate–dyed silk fabric were attributed to a chemical reaction between –COOH groups and amino acid side chains in silk fabric, the mechanism proposed in this work. Increasing sodium citrate resulted in improved mechanical properties and whiteness, but the opposite trend was found with increasing dyeing temperature. An optimum pH for dyeing the silk fabric in this work was 5.5. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1000–1007, 2004
Grafting of acrylic monomers onto cotton fabric using an activated cellulose thiocarbonate–azobisisobutyronitrile redox system
Authors: Zahran M. K. , Morsy M. , Mahmoud R. I. 
Published: November 2003

AbstractThe feasibility of a cellulose thiocarbonate–azobisisobutyronitrile (AIBN) initiation system to induce graft copolymerization of methyl methacrylate (MMA) and other acrylic monomers onto cotton fabric was investigated. Other acrylic monomers were acrylic acid, acrylonitrile, and methyl acrylate. The initiation system under investigation was highly activated in the presence of a metal‐ion reductant or a metal‐ion oxidant in the polymerization medium. A number of variables in the grafting reaction were studied, including AIBN concentration, pH of the polymerization medium, nature of substrate, monomer concentration, duration and temperature of polymerization, and composition of the solvent/water polymerization medium. The solvents used were methanol, isopropanol, 1,4‐dioxane, cyclohexane, benzene, dimethyl formamide, and dimethyl sulfoxide. There were optimal concentrations of AIBN (5 mmol/L), MMA (8%), Fe2+ (0.1 mmol/L), Mn2+ (8 mmol/L), and Fe3+ (2 mmol/L). A polymerization medium of pH 2 and temperature of 70°C constituted the optimal conditions for grafting. The methanol/water mixture constituted the most favorable reaction medium for grafting MMA onto cotton fabric by using the Fe2+–cellulose thiocarbonate–AIBN redox system. MMA was superior to other monomers for grafting. The unmodified cotton cellulose showed very little tendency to be grafted with MMA compared with the chemically modified cellulosic substrate. A tentative mechanism for the grafting reaction was proposed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1261–1274, 2004
On‐line monitoring of the evolution of number of particles in emulsion polymerization by conductivity measurements. II. Model validation
Authors: Santos A. F. , Lima E. L. , Pinto J. C. , Graillat C. , McKenna T. F. 
Published: November 2003

AbstractA model to describe the evolution of conductivity measurements in emulsion polymerizations was presented in the first part of this work [Santos et al., J Appl Polym Sci, 2002]. The model was built on the assumption that surfactant is partitioned among the three principle phases of the polymerizing latex. Model parameters were estimated by fitting the model responses to experimental conductivity data obtained in different runs performed with similar solids content, reactor temperature, and initiator concentration. A soft‐sensor strategy was then proposed for monitoring of the number of polymer particles (Np) by combining the conductivity model with the available conversion, temperature, and conductivity signals. The main objective of the current work is to validate the conductivity model in a broader range of operation conditions, to follow the evolution of Np (nucleation/coagulation) on‐line under different reaction conditions. A series of batch and semibatch polymerization runs were carried out aiming to evaluate the model performance when different solids content, surfactant concentration, and reactor temperatures are used. Additionally, simulation studies were performed to assess the model sensitivity to the fluctuations of the conversion and temperature signals. Results showed that the model is able to perform accurate predictions of Np even when disturbances of ±2°C in temperature and ±0.03 in monomer conversion take place during the polymerization process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 941–952, 2004
Absorption characteristics of alginate wound dressings
Authors: Qin Yimin 
Published: November 2003

AbstractThis study describes an investigation on the absorption characteristics of alginate wound dressings. The fluid that is absorbed by the dressing is divided into that which is held inside the fiber in the fiber structure and that which is held between the fibers in the textile structure. A number of dressings with different fiber structure and textile structure were studied and their effects on the absorption characteristics of the dressings were analyzed. It was found that a significant part of the absorption took place inside the fiber structure, in addition to the liquid held between fibers in the textile structure. High M alginate and high G calcium/sodium alginate fibers absorbed more fluid into the fiber than high G calcium alginate fiber, resulting in a better gelling ability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 953–957, 2004
Absolute online monitoring of acrylic acid polymerization and the effect of salt and pH on reaction kinetics
Authors: Çatalgil‐Giz Huceste , Giz Ahmet , Alb Alina M. , Reed Wayne F. 
Published: November 2003

AbstractUsing recently introduced Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP), the kinetics of acrylic acid polymerization was studied. ACOMP yields the absolute weight‐averaged mass (Mw), monomer conversion, and other quantities. As the initiator concentration increased, it was shown that the rate increased and the Mw decreased as in regular free‐radical polymerization. The effect of salt on acrylic acid polymerization in an aqueous solution was investigated. The polymerization rate and Mw both decreased with an increasing salt concentration. ACOMP molecular weights were also compared with size‐exclusion chromatography on aliquots periodically withdrawn during the reaction, and good agreement was found. The effect of the pH on the rate and the molecular weight was also investigated, and when the medium pH was changed from 2 to 5 with sodium hydroxide, the rate and Mw both decreased as the pH increased. Light‐scattering results of reaction end products in the reference solvent showed that molecules synthesized at higher pH were in a more expanded form. When equimolar sodium hydroxide was added to the acrylic acid (pH ≅ 5) and sodium acrylate formed, adding salt did not effect the reaction kinetics of the poly(sodium acrylate); its effect on the products was a relatively minor decrease of Mw. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1352–1359, 2004
Recombinant human elastin polypeptides self‐assemble into biomaterials with elastin‐like properties
Authors: Bellingham Catherine M. , Lillie Margo A. , Gosline John M. , Wright Glenda M. , Starcher Barry C. , Bailey Allen J. , Woodhouse Kimberly A. , Keeley Fred W. 
Published: November 2003

AbstractProcesses involving self‐assembly of monomeric units into organized polymeric arrays are currently the subject of much attention, particularly in the areas of nanotechnology and biomaterials. One biological example of a protein polymer with potential for self‐organization is elastin. Elastin is the extracellular matrix protein that imparts the properties of extensibility and elastic recoil to large arteries, lung parenchyma, and other tissues. Tropoelastin, the ≈70 kDa soluble monomeric form of elastin, is highly nonpolar in character, consisting essentially of 34 alternating hydrophobic and crosslinking domains. Crosslinking domains contain the lysine residues destined to form the covalent intermolecular crosslinks that stabilize the polymer. We and others have suggested that the hydrophobic domains are sites of interactions that contribute to juxtaposition of lysine residues in preparation for crosslink formation. Here, using recombinant polypeptides based on sequences in human elastin, we demonstrate that as few as three hydrophobic domains flanking two crosslinking domains are sufficient to support a self‐assembly process that aligns lysines for zero‐length crosslinking, resulting in formation of the crosslinks of native elastin. This process allows fabrication of a polymeric matrix with solubility and mechanical properties similar to those of native elastin. © 2003 Wiley Periodicals, Inc. Biopolymers 70: 445–455, 2003
Distribution of tyrosine hydroxylase, dopamine, and serotonin in the central nervous system of amphioxus (Branchiostoma lanceolatum): Implications for the evolution of catecholamine systems in vertebrates
Authors: Moret Frédéric , Guilland Jean‐Claude , Coudouel Sophie , Rochette Luc , Vernier Philippe 
Published: November 2003

AbstractTo investigate the evolutionary transition that has shaped the catecholaminergic systems of vertebrates, the organization of catecholamine‐synthesizing neurons and the nature of the catecholamines were examined in the central nervous system of adult amphioxus (Branchiostoma lanceolatum), a cephalochordate. We isolated a gene transcript encoding tyrosine hydroxylase (TH), the limiting enzyme of catecholamine biosynthesis, and studied its distribution together with that of dopamine and serotonin. Dopamine and TH are found in the same neurons of which they are three separate populations. Two are located in the anterior brain, the first being dorsal and lying in a row and the second being more posterior and lateral. A third population comprising a few dorsal commissural neurons was found in the posterior brain. The anterior dopaminergic cells innervate the ventral commissure of the cephalic vesicle, the hindbrain, and the spinal cord. A serotonin‐containing cell group is located in the same plane as the second dopaminergic cell population but is more caudal, marking the probable transition between anterior brain and hindbrain, as deduced from gene expression patterns. The overall distribution of dopaminergic and serotoninergic systems is similar in amphioxus and vertebrate central nervous system and could be an ancestral character of chordates. As assayed by high‐performance liquid chromatrography and electrochemical detection, significant amounts of dopamine and octopamine, but not of noradrenaline, are present in amphioxus head. This finding is consistent with data obtained from most prostomian species. We conclude that the noradrenergic system is probably an innovation of vertebrates that appeared along with the neural crest and specific hindbrain nuclei. J. Comp. Neurol. 468:135–150, 2004. © 2003 Wiley‐Liss, Inc.
Expression of the KCl cotransporter KCC2 parallels neuronal maturation and the emergence of low intracellular chloride
Authors: Stein Valentin , Hermans‐Borgmeyer Irm , Jentsch Thomas J. , Hübner Christian A. 
Published: November 2003

AbstractFast synaptic inhibition in the adult central nervous system (CNS) is mediated by GABA and glycine. During early development GABA acts as an excitatory neurotransmitter, which is deemed to be important for the maturation of the CNS. During development GABAergic responses undergo a switch from excitatory to inhibitory. This switch is correlated with upregulation of KCC2, the neuronal isoform of the potassium‐chloride cotransporter family. KCC2 lowers the intraneuronal chloride concentration below its electrochemical equilibrium. KCC2 activity is thought to depend on phosphorylation by endogenous tyrosine kinases. Here, we analyzed the expression pattern of KCC2 during murine embryonic and postnatal development by in situ hybridization and Western blot analysis. KCC2 expression paralleled neuronal differentiation and preceded the decline of the GABA reversal potential (EGABA) in spinal cord motoneurons and hippocampal pyramidal cells. The adult inhibitory response to GABA was established earlier in the spinal cord than in the hippocampus. Phosphorylated KCC2 protein was already present early in development when the functional GABA switch had not yet occurred. Thus, tyrosine‐phosphorylation seems to be less important than the transcriptional upregulation of KCC2. J. Comp. Neurol. 468:57–64, 2004. © 2003 Wiley‐Liss, Inc.
Characterization of dynamics and reactivities of solvated ions byab initiosimulations
Authors: Hofer Thomas S. , Tran Hung T. , Schwenk Christian F. , Rode Bernd M. 
Published: November 2003

AbstractBased on a systematic investigation of trajectories ofab initioquantum mechanical/molecular mechanical simulations of numerous cations in water a standardized procedure for the evaluation of mean ligand residence times is proposed. For the characterization of reactivity and structure‐breaking/structure‐forming properties of the ions a measure is derived from the mean residence times calculated with different time limits. It is shown thatab initiosimulations can provide much insight into ultrafast dynamics that are presently not easily accessible by experiment. © 2003 Wiley Periodicals, Inc. J Comput Chem 25: 211–217, 2004
Conformational changes in poly(vinyl alcohol)‐graft‐polyacrylamide in aqueous solutions vs graft content
Authors: Kutsevol Nataliya , Zheltonozhskaya Tatyana , Melnik Nataliya , Guenet Jean‐Michel , Syromyatnikov Vladimir 
Published: November 2003

AbstractConformational changes have been studied in intramolecular polymer‐polymer complexes (intraPC) of graft copolymers of poly(acrylamide) and poly(vinyl alcohol) (PVA‐g‐PAA) with various numbers of grafts (4‐42) per molecule as a function of temperature and copolymer concentration. It is shown that the magnitude of conformational change depends on the grafts content while the temperature range over which the conformation changes occur is essentially determined by copolymer concentration. The conformational changes are reversible on heating and cooling.
Photo‐ageing of a thermoplastic aromatic polyurethane in contact with artificial sweat
Authors: Dubois Claude , Vebrel Joël , Rigny‐Bourgeois Valérie , Grohens Yves 
Published: November 2003

AbstractAn artificial photo‐ageing cell was adapted in order to study the behaviour of polymers partly immersed in artificial sweat. The goal was to select polymers and to transform them into objects that come in contact with the skin. The polymer studied in this paper is a thermoplastic aromatic polyurethane (TPU) with the following characteristics: soft, transparent, lightly yellow coloured and hypoallergenic. The ageing of this polymer was studied with or without the presence of light stabilizers, and with or without sweat.The physico‐chemical changes in the TPU were analysed step by step during ageing. The differences in mass variation between the different ageing modes (with or without sweat; with or without stabilizers) provided information on the hydrolytic action of the sweat. The chemical changes that occurred around the irradiated or immersed surfaces were studied by IR‐ATR spectrometry in order to characterize the photo‐oxidation and hydrolytic effects as well as their coupling. The morphological modifications of the polymer were recorded by differential scanning calorimetry.
A comparative study of the rheological and structural properties of gelatin gels of mammalian and fish origins
Authors: Simon Anne , Grohens Yves , Vandanjon Laurent , Bourseau Patrick , Balnois Eric , Levesque Guy 
Published: November 2003

AbstractFrom a long time, the traditional source of collagen has been mammals wastes, mainly bovine and porcine skins and bones. This study undertakes a comparative analysis of the viscoelastic behaviour and the structural properties of gelatin gels from both mammalian and fish origins.All the rheological measurements were carried out within the linear viscoelastic region for gelatin gels and tentatively related to structural characteristics. At a given concentration the pig gelatine exhibits a high storage modulus, G′, which indicates that the gel is stiffer than the fish one. The helical structures content measured by the specific rotation, [α], is also higher for the pig gelatin. Moreover, the gel is denatured in the same range of temperature, namely, around 30°C but the transition is sharper for fish gelatine. These differences between the gelatins lie in the amino‐acid composition and molecular weight distribution which may influence the nature of the interchain junctions yielding to various gel mesostruture.
An energy–momentum conserving algorithm for non‐linear hypoelastic constitutive models
Authors: Noels L. , Stainier L. , Ponthot J. P. 
Published: November 2003

AbstractThis paper presents an extension of the energy momentum conserving algorithm, usually developed for hyperelastic constitutive models, to the hypoelastic constitutive models. For such a material no potential can be defined, and thus the conservation of the energy is ensured only if the elastic work of the deformation can be restored by the scheme. We propose a new expression of internal forces at the element level which is shown to verify this property. We also demonstrate that the work of plastic deformation is positive and consistent with the material model. Finally several numerical applications are presented. Copyright © 2003 John Wiley & Sons, Ltd.
Management of childhood constipation: parents’ experiences
Authors: Farrell Mike , Holmes Gill , Coldicutt Pat , Peak Matthew 
Published: November 2003

Background.  Constipation in childhood is common and places a burden on child health services. Whilst constipation can have a variety of causes, for most children it is usually non‐organic and requires limited intervention. It has been suggested that health professionals can resent consultations for such a common problem, believing them to be inappropriate. However, they can underestimate the impact of this condition, leading to adverse clinical effects, as well as parental dissatisfaction. Little research has explored parents’ experiences of consulting health professionals about the management of childhood constipation.Aim.  To explore parents’ experiences of consulting health professionals about management of childhood constipation and to use the findings to inform more effective therapeutic encounters when responding to parental concerns.Methods.  A phenomenological approach was adopted, using in‐depth interviews with parents of 14 children receiving health interventions for constipation.Findings.  Six themes emerged from analysis including: ‘enduring and extreme constipation’, which reflected the substantial and sustained impact of the child's constipation; ‘dismissed and fobbed off’, which captured parents’ feelings that their concerns were frequently dismissed by health professionals; ‘asserting the need for action’, a perception that they had reached a point at which they had to demand some intervention; and ‘validation and acknowledgement’, which reflected acknowledgment that, finally, their concerns for their child had been taken seriously and acted on.Discussion.  The findings indicate a failure by some health professionals to appreciate fully the significance of childhood constipation, thereby appearing to be unconcerned and insensitive to the needs of child and family. The impact of this is a potential loss of trust in health professionals by parents, which can then have implications for how they perceive and access health services for management of this common childhood problem. The findings offer an insight into parental experiences and indicate the need for a more sensitive approach during health consultations.
Effect of music on chronic osteoarthritis pain in older people
Authors: McCaffrey Ruth , Freeman Edward 
Published: November 2003

Background.  Osteoarthritis is the most common degenerative disease in humans. It usually begins in middle age and is progressive. Chronic pain in older people presents a significant obstacle in maintaining function and independence. Previous studies have shown that music can improve motivation, elevate mood, and increase feelings of control in older people.Purpose.  The purpose of this randomized clinical trial was to examine the influence of music as a nursing intervention on osteoarthritis pain in elders.Method.  Data were collected using the short form of the McGill Pain Questionnaire with 66 elders suffering from chronic osteoarthritis pain. Differences in perceptions of pain were measured over 14 days in an experimental group who listened to music for 20 minutes daily and a control group who sat quietly for 20 minutes daily. All participants completed the Short Form McGill Pain Questionnaire (SF‐MPQ) on day 1, 7, and 14 of the study.Results.  Results of t‐tests indicated that those who listened to music had less pain on both the Pain Rating Index on day 1 (P = 0·001), day 7 (P = 0·001) and day 14 (P = 0·001) and on the Visual Analogue Scale on day 1 (P = 0·001), day 7 (P = 0·001) and day 14 (P = 0·001), when compared with those who sat quietly and did not listen to music. A repeated measure analysis of variance controlling for pretest measures demonstrated a significant decrease in pain among experimental group participants when compared with the control group on the pain descriptor section of the SF‐MPQ (P = 0·001) and the visual analogue portion of the SF‐MPQ (P = 0·001).Conclusion.  Listening to music was an effective nursing intervention for the reduction of chronic osteoarthritis pain in the community‐dwelling elders in this study.
Canine Osteosarcoma of the Penile Bone
Authors: Bleier T. , Lewitschek H. P. , Reinacher M. 
Published: November 2003

SummaryA 13‐year‐old mixed breed dog was presented with difficulties to urinate, blood in the urine and a nodule at the root of the penis. The penis was completely resected, and an osteosarcoma of the penile bone was diagnosed. Radiographically, there was no evidence to suggest tumours in other bones or distant metastases. The dog was euthanized as a consequence of tumour recurrence after 2 months. This is believed to be the first reported case of a primary osteosarcoma of the penile bone.