bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal degradation of a brominated bisphenol a derivative
Authors: Luda M. P. , Balabanovich A. I. , Hornung A. , Camino G. 
Published: January 2004

AbstractThe thermal degradation of 2,6,2′,6′–tetrabromo‐4,4′‐isopropylidene‐di phenol (tetrabromobisphenol A) (TBBPA) has been investigated and a mechanism for its thermal degradation is suggested. TBBPA is a comonomer widely used in epoxy and in unsaturated polyester resins to impart fire retardance. These resins find a common use in electric and electronic equipment. The presence of bromine atoms is the key factor in fire retardant activity, while on the other hand it represents an ecological problem when pyrolytic recycling is programmed at the end of the useful life of such items. However, pyrolysis is the more advantageous recycling system for thermosetting resins and thus efforts should be made to control the pyrolysis in order to avoid or minimize the development of toxics. Homolytic scission of the aromatic bromine and condensation of aromatic bromine with phenolic hydroxyl are the main processes occurring in the range 270–340°C. A large amount of charred residue is left as a consequence of condensation reactions. HBr and brominated phenols and bisphenols are the main volatile products formed. Brominated dibenzodioxins structures are included in the charred residue and not evolved in the volatile phases. Copyright © 2003 John Wiley & Sons, Ltd.
Processing, properties and stability of biodegradable composites based on Mater‐Bi® and cellulose fibres
Authors: Puglia D. , Tomassucci A. , Kenny J. M. 
Published: January 2004

AbstractIn this work, the behaviour of biocomposites obtained by the addition of flax cellulose pulp to Mater‐Bi®, a commercial thermoplastic matrix based on starch, has been studied in comparison with traditional glass fibre composites. The composites were produced by compounding with a twin‐screw extruder. Depending on the kind of fibre, reinforcement contents of 10–40% were obtained. The mechanical behaviour, both in normal conditions and after water absorption, was analysed. It has been noted that the addition of cellulose pulp increases the composite modulus more than glass fibre: in fact, a poor adhesion of the interface between the glass fibre and Mater‐Bi® has been observed. The thermal degradation behaviour of the composite has been studied by thermogravimetric analysis (TGA). Different degradation peaks have been observed and the activation energies, related to the main peak, have been calculated. The addition of cellulose pulp produces better mechanical properties and higher thermal stability. Copyright © 2003 John Wiley & Sons, Ltd.
Electrically adjustable thermotropic windows based on polymer gels
Authors: Gyenes Tamás , Szilágyi András , Lohonyai Tünde , Zrínyi Miklós 
Published: January 2004

AbstractSeveral attempts have been made recently in order to develop “Smart” windows, which can moderate light and heat intensities. Based upon the phase transitions of polymer gels, a novel electrically adjustable window, which includes a gel layer, has been developed in our laboratory. Unlike other electrically controlled structures, the optical properties of the gel layer are abruptly modified by the Joule heat of audio frequency AC current. The so‐called “gel‐glass” becomes opaque when the temperature exceeds a critical value and changes back to its original transparent state when it is cooled down again. This method results in fast control and relatively low operational cost. Two types of gel‐glasses—active and passive structures—have been developed and investigated. In this paper, we demonstrate the structural build‐up and working of these novel electrically adjustable thermotropic windows. Experimental studies have been made at different frequencies and voltages. The optical properties, as well as the energy balance of the systems, have been reported. Copyright © 2003 John Wiley & Sons, Ltd.
Atomic force microscopic and encrustation studies of novel prospective polyisobutylene‐based thermoplastic elastomeric biomaterials
Authors: Puskas Judit E. , Chen Yaohong , Antony Prince , Kwon Yongmoon , Kovar Milan , Harbottle Robert R. , De Jong Kathy , Norton Peter R. , Cadieux Peter , Burton Jeremy , Reid Gregor , Beiko Darren , Watterson James D. , Denstedt John 
Published: January 2004

AbstractThis paper investigates the surface morphology of polyisobutylene–polystyrene (PIB–PS) block‐type thermoplastic elastomers, emerging new biomaterials, by atomic force microscopy (AFM). A novel aborescent PIB–PS block polymer (AR15) was synthesized through inimer‐type living carbocationic polymerization and characterized in comparison with a semi‐commercial PIB–PS thermoplastic elastomer (TPE) (TS30). Tapping‐mode AFM revealed that PS spheres with a domain size of 45–60 nm were very irregularly distributed in the continuous PIB phase of the aborescent AR15 polymer, whereas ordered and mixed cylindrical/lamellar morphology with 25–31 nm hard phase appeared in a linear TS30 triblock polymer. Moreover, AFM revealed rough surface features of a 1 mm thick compression molded TS30 polymer disk coated with a probiotic protein. AR15 disks were used for in vivo urinary tract encrustation study. Encrustation of the PIB–PS disks was comparable or better than that of medical‐grade silicone rubber. The preliminary results imply the prospect of PIB–PS thermoplastic elastomers as emerging soft biomaterials. Copyright © 2003 John Wiley & Sons, Ltd.
Interaction of non‐ionic hydrogels with small aromatic molecules
Authors: Kosik Katalin , Geissler Erik , Zrínyi Miklós , László Krisztina 
Published: January 2004

AbstractMeasurements are reported on the swelling behaviour at 20°C of poly (N‐isopropylacrylamide) (PNIPA) gels in aqueous solutions of two weak aromatic acids, phenol and resorcinol. For solute concentrations below 45 mmol/l, the uptake of these solutions is similar. Phenol exhibits an excess equilibrium concentration inside the gel of 5% over that in the surrounding bath, while for resorcinol, the excess is found to be 12%. At 50 mmol/l solute concentration, both systems display a volume transition accompanied by expulsion of the solvent. The solubility limits in water of these aromatic compounds are significantly different (870 and 9080 mmol/l, respectively), and are far above this critical concentration. In the collapsed condition, the expelled liquid spreads on the surface of the phenol‐treated gel, while an ordered arrangement of separate droplets is generated in the case of resorcinol. In the latter case, an acute contact angle was observed. Copyright © 2003 John Wiley & Sons, Ltd.
Preparation possibilities of aluminum and silicon‐containing hybrid polymer systems
Authors: Sinkó Katalin , Fél Kornél , Zrínyi Miklós 
Published: January 2004

AbstractThe main aim of the present work is to study the relationship between the synthesis–structure–property triangle of hybrid polymer materials. The investigations have been focused on the effect of synthesis parameters and on the materials structures over the atomic and supramolecular range. An important task was to improve the strength of the low‐density aluminum‐ and silicon‐containing oxide systems produced by sol–gel technology. The addition of organic polymers (e.g. PDMS) to the inorganic component increased the strength of the aluminosilicate aerogels two‐ or eightfold depending on the preparation conditions. The parameters of the synthesis had a strong influence on the structure, the structural parameters such as porosity, or even on the location of the aluminum atoms in the gel structure. The application of oligomeric inorganic particles resulted in a more homogeneous gel structure than that of monomer inorganic precursors (aluminum nitrate and TEOS). In the samples produced from oligomeric aluminosilicate particles, a fractal structure with high aluminum incorporation has been dominant. The structure obtained from monomer inorganic precursors has been built up from weak associates of aggregates. The elasticity and the homogeneity of the gel samples increased by treatment with some excess TEOS before the gel point. Copyright © 2003 John Wiley & Sons, Ltd.
Silylation of wood for potential protection against biodegradation. An ATR‐FTIR, ESCA and contact angle study
Authors: Mohammed‐Ziegler Ildikó , Marosi György , Matkó Szabolcs , Hórvölgyi Zoltán , Tóth András 
Published: January 2004

AbstractSurfaces of three European (English oak, ash and Scots pine) and three tropical (teak, cloves and neem) wood species were silylated with chlorotrimethylsilane, octadecyltrichlorosilane, trimethylsilyl N,N‐dimethylcarbamate and an alkoxysilane‐terminated surfactant introducing diethoxy‐silyl groups onto the surface structure. For the study of surface composition, ATR‐FTIR and ESCA measurements were performed. The hydrophobicity of the surfaces was studied by contact angle determinations. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis, characterization and biomedical applications of functionalized polypyrrole‐coated polystyrene latex particles
Authors: Bousalem S. , Yassar A. , Basinska T. , Miksa B. , Slomkowski S. , Azioune A. , Chehimi M. M. 
Published: January 2004

AbstractN‐hydroxysuccinimide‐functionalized polypyrrole (PPy–NHS) coated onto polystyrene (PS) latex particles were prepared by the in situ copolymerization of pyrrole and the active ester‐functionalized pyrrole (pyrrole–NHS) in the presence of bare PS substrates. The initial comonomer concentration ratios were 25/75 and 50/50 for pyrrole and pyrrole–NHS, respectively. PS particles were prepared by two methods: emulsion polymerization, leading to particle sizes in the 450–500 nm range, and dispersion polymerization using poly(N‐vinylpyrrolidone) (PNVP) as a steric stabilizer. The polypyrrole‐coated PS particles (PS–PPy) were characterized in terms of particle size, surface charge and surface chemical composition. For the “emulsion” PS coated with polypyrrole, the particles were evaluated as bioadsorbents of human serum albumin (HSA). It is believed that the proteins attach themselves by covalent bonds at the surfaces of NHS‐functionalized PPy–PS particles. It is shown that the maximum adsorption levels off at 0.2 mg/m2 in the case of the 50/50 initial ratio concentration but only to 0.02 mg/m2 in the case of the 25/75 ratio, an indication that a higher concentration of surface reactive groups hamper the covalent attachment of HSA at the surfaces of polypyrrole particles. Copyright © 2003 John Wiley & Sons, Ltd.
Nature of water molecules in hydrogels based on a liquid crystalline cellulose derivative
Authors: Wojciechowski P. , Joachimiak A. , Halamus T. 
Published: January 2004

AbstractThe status and nature of water molecules in hydrogels with a liquid crystalline organization of the polymer network based on a biopolymer were investigated. Liquid crystalline (LC) hydrogels were obtained in situ by the photopolymerization of acrylic acid into the lyotropic liquid crystalline phase of (2‐hydroxypropyl)cellulose in a solvent mixture of water and acrylic acid. The photopolymerization of acrylic acid in the lyotropic liquid crystalline phase at room temperature gives a hydrogel in which liquid crystalline order and water are retained. The liquid crystalline hydrogel contains water, which originates from the composition of the lyotropic liquid crystalline phase, and may also contain water after immersion in liquid water. The water molecule characteristics were examined by means of differential scanning calorimetry, dielectric relaxation spectroscopy, and differential scanning calorimetry coupled with thermo‐optical measurements. The swelling data were obtained by using a weighing method. The investigations reveal the different nature of the two above‐mentioned water types. For the water from the composition of the lyotropic liquid crystalline phase, the phase transitions—typical for the bulk water—were not observed, in contract to the water after swelling of the liquid crystalline hydrogel in the liquid water. The results of the measurements suggest that water, which comes from the composition of the lyotropic liquid crystalline phase, forms—together with a polymer network—a microstructure, stabilized by this water. The water, after swelling of the LC hydrogel in the liquid water, is separated in the pores of the hydrogel and exhibits the phase transitions of the bulk water. Copyright © 2003 John Wiley & Sons, Ltd.
Lithocholic‐acid‐containing poly(ester–anhydride)s
Authors: Krasko Michal Y. , Ezra Aviva , Domb Abraham J. 
Published: January 2004

AbstractNew degradable poly(ester‐anhydride)s were prepared by melt polycondensation of poly(sebacic acid) (PSA), transesterified by different amounts (30–90%) of lithocholic acid (LCA), a natural hydroxy bile acid. Transesterification of PSA is a one‐pot reaction that starts with a high‐molecular‐weight polymer based on anhydride bonds and yields polymer based on random anhydride–ester bonds. A systematic study of the synthesis, characterization, degradation in vitro, drug release, and stability of these polymers was performed. Polymers with molecular weights (Mw) in the range of 12 000–115 000 and melting points in the range of 55–112 °C were obtained for 30–90% of lithocholic acid content. NMR and IR spectroscopic analyses indicate the formation of ester bonds in the polyanhydride backbone. The experimental results fit the calculated molecular weight, with the highest Mw obtained for a 4:6 PSA–LCA ratio. The study shows that some of these new degradable copolymers can be potentially used as carriers for the controlled release of drugs. Copyright © 2003 John Wiley & Sons, Ltd.
Examination of drug release from hydrogels
Authors: Erős István , Csóka Ildikó , Csányi Erzsébet , Takács‐Wormsdorff Tünde 
Published: January 2004

AbstractThe liberation of several important active agents was studied from hydrogels produced from new macromolecular substances. Liberation was examined with an in vitro method, with a Hanson's vertical diffusion cell. Polymers were used in an increasing concentration, while the quantity of active agents was constant. Several quantitative relationships were established after the examination of liberation from 240 drug‐containing gels. A power function was found between the concentration of the polymers and the quantity of the liberated active agents, while a logarithmic relationship existed between the viscosity of the gels and the extent of liberation. Interactions between the active agent and the vehicles can be inferred from the rheological functions as well as from the constants of the liberation versus concentration and liberation versus viscosity functions. Copyright © 2003 John Wiley & Sons, Ltd.
The risk of esophageal obstruction associated with an anti‐allergy medication (Claritin‐D® 24‐Hour—original formulation)
Authors: Manda Bharati , Drinkard Carol R. , Shatin Deborah , Graham David J. 
Published: January 2004

AbstractPurposeTo investigate a possible increased risk of esophageal obstruction among users of loratadine and pseudoephedrine (Claritin‐D® 24‐Hour ‘C‐D 24’, the original, round, extended‐release formulation) compared to two other tablet formulations of loratadine.MethodsPharmacy data of 12 managed care plans were screened to identify users in the three groups from 1 September 1996 to 31 December 1998. Users with a medical claim following their first loratadine prescription (Index prescription) indicating an esophageal obstruction or endoscopic procedure were considered claims‐identified cases. Medical records were reviewed to validate case status.ResultsThere were 233 901 users (61% female) and 245 claims‐identified cases occurring within 30 days after the first prescription. The incidence rate per 10 000 users of claims‐identified cases occurring on the Index prescription date was higher among C‐D 24 users (IR = 1.4) than Claritin® Regular (C‐R) users (IR = 0.07; p < 0.002) or Claritin‐D® 12‐Hour (C‐D 12) users (IR = 0.3; p > 0.05). Medical record review of 15 claims‐identified cases confirmed two cases of acute esophageal obstruction, both among C‐D 24 users.ConclusionsClaims‐based analysis suggested an increased risk of endoscopic procedures on the Index date among C‐D 24 users compared to C‐R users. However, after medical record review, the study did not provide conclusive evidence of an association between C‐D 24 use and esophageal obstruction. This study highlights the importance of validating findings from claims data using medical records. Copyright © 2003 John Wiley & Sons, Ltd.
How well do patients report noncompliance with antihypertensive medications?: a comparison of self‐report versus filled prescriptions
Authors: Wang Philip S. , Benner Joshua S. , Glynn Robert J. , Winkelmayer Wolfgang C. , Mogun Helen , Avorn Jerry 
Published: January 2004

AbstractPurposeTo address poor patient compliance with antihypertensives, clinicians and researchers need accurate measures of adherence with prescribed regimens. Although self‐reports are often the only means available in routine practice, their accuracy and agreement with other data sources remain questionable.MethodsA telephone survey was conducted on 200 hypertensive patients treated with a single antihypertensive agent in a large health maintenance organization (HMO) or a Veterans Affairs medical center (VAMC) to obtain self‐reports of the frequency of missing antihypertensive therapy. We then analyzed records of all filled prescriptions to calculate the number of days that patients actually had antihypertensive medications available for use. Agreement between the two data sources was measured with correlation coefficients and kappa statistics. Logistic regression models were used to identify demographic, clinical and psychosocial correlates of overstating compliance.ResultsThere was very poor agreement between self‐reported compliance and days actually covered by filled prescriptions (Spearman correlation coefficient = 0.15; 95%CI: 0.01, 0.28). Very poor agreement was also observed between a categorical measure of self‐reported compliance (ever vs. never missing a dose) and categories of actual compliance defined by filled prescriptions (< 80% vs > 80% of days covered; kappa = 0.12, 95%CI: −0.02, 0.26). Surprisingly, few factors were associated with inaccurate self‐reporting in either crude or adjusted analyses; fewer visits to health care providers was significantly associated with overstating compliance.ConclusionsCompliance was markedly overstated in this sample of patients and few characteristics identified those who reported more versus less accurately. Clinicians and researchers who rely on self‐reports should be aware of these limits and should take steps to enhance their accuracy. Copyright © 2003 John Wiley & Sons, Ltd.
Infant vaccinations and childhood asthma among full‐term infants
Authors: Maher Julie E. , Mullooly John P. , Drew Lois , DeStefano Frank 
Published: January 2004

AbstractPurposeTo determine if infant vaccinations are associated with childhood asthma among full‐term infants. The secondary objective was to describe relationships between characteristics of infant wheezing and childhood asthma.MethodsWe used baseline data from a study of infant wheezing that selected full‐term infants born into a health maintenance organization (HMO) during 1991–1994, continuously enrolled for at least 12 months and without perinatal pulmonary or other selected conditions. Information had been abstracted for infancy (0–18 months) regarding wheezing, vaccinations and asthma risk factors. Using automated data, we identified asthma cases in 1998 among those enrolled for at least 6 months during the year.ResultsA total of 1778 full‐term infants met our study criterion and 9% had asthma in 1998. Childhood asthma was not significantly associated with having received Hepatitis B vaccine or age at first Hepatitis B vaccine; number of whole‐cell pertussis, Haemophilis influenzae type b or oral polio vaccine doses; having received measles, mumps, rubella vaccine; or total number of vaccine doses combined. Childhood asthma was significantly associated with number of infant wheezing episodes.ConclusionsOur findings do not support concerns that vaccines are associated with increased risk of asthma but confirm that frequency of infant wheezing is associated with childhood asthma. Copyright © 2003 John Wiley & Sons, Ltd.
Reduction in the therapeutic intensity of abortive migraine drug use during ACE inhibition therapy—a pilot study
Authors: Rahimtoola H. , Buurma H. , Tijssen C. C. , Leufkens H. G. , Egberts A. C. G. 
Published: January 2004

AbstractIntroductionSince a few case reports have demonstrated some beneficial effects of angiotensin converting enzyme (ACE) inhibitors in migraine prevention, we were interested in studying the impact of ACE inhibitors and angiotensin II receptor antagonists (Ang II) on the consumption of specific abortive migraine drugs and, therefore, indirectly on the frequency of migraine attacks.MethodsData from a large prescription database involving 95 patients initiating a specific abortive migraine drug (ergotamine or a triptan) and subsequently treated with either an ACE inhibitor or angiotensin receptor antagonist (index group: ACE/Ang II) or diuretic (reference group) were analysed. The effects of ACE/Ang II inhibition as well as diuretic therapy on reducing the frequency of migraine attacks were assessed by measuring the mean consumption of abortive migraine drug use, in DDDs per month (‘therapeutic intensity’), before, during and after ACE/Ang II or diuretic therapy. A ‘therapeutic fluctuation intensity estimate’ of abortive migraine drug use for all patients was likewise calculated.ResultsOn an individual level, the therapeutic intensity (TI) fluctuation estimate, ‘during’ relative to ‘before’ ACE diuretic therapy, was significantly larger for the ACE/Ang II group (62% reduction) than for the diuretic group (24% reduction) (p = 0.02). For patients who continued abortive migraine drug use during and after ACE/Ang II or diuretic therapy, a significantly larger reduction in this estimate was observed during ACE/Ang II inhibition (68.9%) compared to during diuretic therapy (10.5% increase) (p = 0.004). The TI fluctuation estimate, after relative to ‘during’, had increased by 50.3% after ACE/Ang II inhibition and had reduced by 22.2% after diuretic treatment (p = 0.1).ConclusionsA clear reduction in the TI of abortive migraine drug use during the use of ACE inhibitors as compared to diuretic treatment was observed. Our findings may indirectly support a positive effect of ACE/Ang II inhibition on the frequency and severity of migraine attacks, as observed in other studies and reports. Copyright © 2003 John Wiley & Sons, Ltd.