bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct Observation of Specific Interaction between Enzyme-substrate Complexes Using Colloidal Probe Atomic Force Microscopy
Authors: Suzuki Takehiro , Zhang Yuan-Wei , Koyama Tanetoshi , Sasaki Darryl Y , Kurihara Kazue
Published: April 2004

The interactions between the enzyme-substrate complex of heptaprenyl diphosphate synthase were directly investigated using colloidal probe atomic force microscopy. This enzyme is composed of two dissociable subunits which exhibit a catalytic activity only when they are associated together in the presence of Mg2+ and farnesyl diphosphate (FPP). We observed the adhesive force between the subunits only in the presence of both Mg2+ (0.1 mM) and FPP (15 μM). This is the first direct demonstration of the specific interaction involved in the enzyme reaction.
Excitation Energy Transfer from Self-aggregates of Zinc Chlorins to a Bacteriochlorin in a Silicate Nanocapsule
Authors: Saga Yoshitaka , Akai Sho , Miyatake Tomohiro , Tamiaki Hitoshi
Published: April 2004

Silicate nanocapsules including self-aggregates of zinc methyl 3-devinyl-3-hydroxymethyl-pyropheophorbide-a (zinc chlorin) and methyl bacteriopyropheophorbide-a (bacteriochlorin) were prepared by a sol-gel process. Excitation energy transfer from self-aggregates of zinc chlorins to an energy-accepting bacteriochlorin occurred in the silicate nanocapsule, which was similar to a light-harvesting complex (chlorosome) of green photosynthetic bacteria.
Book Reviews
Authors: Syrett Stephen
Published: April 2004

Southern Europe and the making of the European Union , A.C. Pinto and N.S. Teixeira (eds.) (2002) Social Science Monographs. Boulder NY: University of Columbia Press, xiv + 273 pp., ISBN 0-88033-991-8
British quality, American chaos
Authors: Hilmes Michele
Published: April 2004

This article argues that what has often been presented as a simple, crucial opposition - the British public service broadcasting system versus the US private profit system - in fact demonstrates not only a self-conscious mutual involvement but a set of common objectives that overrides
many of their differences. From each broadcasting system’s earliest history, a mutual construction of a dualism loudly proclaimed can be observed, built largely around matters of ownership, funding, and cultural values. What is suggested here is that each system, in practice, was based
on only versions of central social and economic control that were operationally different: meanwhile, the proclamation of national differences simply served to justify the stifling of an alternative model of ‘popular’ broadcasting, which threatened each system’s dominance
in their respective states.
Day by day, as time goes by
Authors: Domenget Jean Claude
Published: April 2004

As part of a wider research project into the ‘place’ broadcast media have in the lives of the retired in France, a series of interviews with retired people was conducted, providing evidence of the particular place radio-listening practices have in the organization of the
day-today lives of the retired. Five main findings specific to radio listening emerged from the analysis: the ‘bundling’ of activities; radio moving from being an accompaniment to providing company; radio providing precise kinds of ‘get-together’; the feelings at play
in these practices; and loyalty to radio and one station in particular. The study also suggests that whatever changes to listening practices may be brought on by retirement or bereavement, they are rather in the nature of intensifications of loyalty and involvement to programmes and listening
habits that existed before these life-changes.
Editorial
Authors: Garner Ken
Published: April 2004

The title, we thought, said it all. But perhaps it says more than that, more than the simple sum of its parts. In deciding to launch a new scholarly journal, we knew that encouraging debate went with the territory. What we had not envisaged when publishing our call for submissions late
in 2001 was receiving an unsolicited article that implicitly - if only in passing - revealed the thinking that led the Editorial Board to our chosen title. Thankfully, our peer reviewers, drawn from the Editorial Board and International Advisory Board, took the same, strong line with this
submission as the Editor. They insisted it be published in this, our first number.
Book Reviews
Authors: Starkey Guy , Hallett Lawrie , Crisell Andrew
Published: April 2004

The Radio Handbook, Carole Fleming (2002) London: Routledge, 200 pp., ISBN 0-415-15828-1

The Australian Broadcast Journalism Manual, Gail Phillips and Mia Lindgren (2002) Oxford: Oxford University Press, 294pp., ISBN 0-195-51351-7

Web Radio: Radio
Production for Internet Streaming, Chris Priestman (2002) Oxford: Focal Press, 296pp., 296pp., ISBN: 0-240-51635-4

Theatre of Sound: Radio and the Dramatic Imagination, Dermot Rattigan (2002) Dublin: Carysfort Press, 384 pp., ISBN 0-9534-2575-4
International Symposium on Computer Architecture (ISCA 2004)
Authors: Karl Wolfgang
Published: April 2004

Vom 19.–23. Juni 2004 findet die Konferenz “The 31st Annual International Symposium on Computer Architecture (ISCA 2004)” erstmalig in Deutschland statt. Tagungsort ist München, Hotel Bayerischer Hof. Der Beitrag gibt einen kurzen Überblick über die Konferenz und ihre Geschichte.
Konzepte zur Beherrschung der Entwurfskomplexität eingebetteter Systeme (Concepts for the Control of the Complexity of Embedded System Design)
Authors: Klaus Stephan , Huss Sorin A.
Published: April 2004

Das Auffinden einer geeigneten beziehungsweise optimalen Implementierungsvariante verteilter eingebetteter Systeme scheitert immer häufiger an der Komplexität des Lösungsraums und an der Größe der Systeme. Die vorgestellte Spezifikationsmethode mit dem Namen hierarchical CoDesign Model wählt einen hierarchischen Spezifikationsansatz, der die Wiederverwendung von Komponenten unterstützt und eine dynamische Anpassung des Detaillierungsgrades der Spezifikation und damit der Entwurfskomplexität an die aktuellen Anforderungen des Entwicklers ermöglicht. Das Kernstück bilden Input/Output Relationen, welche ein mächtiges Beschreibungsmittel zur Erfassung des Systemverhaltens mit unterschiedlichen Detaillierungsgraden darstellen. Am Beispiel eines MP3 Dekoders wird die Tragfähigkeit der vorgestellten Konzepte demonstriert.
The atomic pair distribution function: past and present
Authors: Billinge Simon J. L.
Published: April 2004

The history of the PDF method is briefly reviewed. Recent results, principally from the Billinge group, are also reviewed.
Obtaining structural information from the atomic pair distribution function
Authors: Proffen Thomas , Page Katharine L.
Published: April 2004

The knowledge of the detailed atomic structure of modern materials is the key to understanding the their macroscopic properties. The atomic pair distribution function (PDF) reveals short-range and medium-range structural information. In this paper we present an overview of refinement and modelling techniques. In short, we will be trying to answer the question: What can I learn from my PDF?
Synchrotron studies of lattice distortions and lattice modulations in complex oxides
Authors: Sinha Sunil K.
Published: April 2004

We review some recent studies of lattice modulations and lattice distortions in single crystals of the layered manganite compound La1.2Sr1.8Mn2O7 and the YBa2Cu3O6+

x
cuprate superconductors obtained from X-ray diffuse scattering using synchrotron radiation. These results confirm the existence of a polaronic liquid (with short-range order) in the paramagnetic insulator phase of the manganite compound, and of lattice modulations (with short-range order) in the cuprate compounds, which co exist with superconductivity down to the lowest temperatures.
Spatial periodicities of defect environments in 57Fe3Al studied by Mössbauer powder diffractometry
Authors: Lin Jiao Y. Y. , Fultz Brent
Published: April 2004

Mössbauer powder diffractometry was used to study partially-ordered 57Fe3Al. Multiple diffraction patterns were measured at Doppler velocities across all nuclear resonances in the sample. The superlattice diffractions were analyzed to provide data on the long-range order of Fe atoms having different numbers of Al neighbors. Comparing experimental data to calculations showed that Fe atoms having three Al atoms as first-nearest neighbors (1nn) have simple cubic long-range order, similar to that of Fe atoms with four Al 1nn. The simple cubic periodicity of Fe atoms with three Al 1nn was significantly lower than expected for homogeneous antisite disorder, however. Monte-Carlo simulations and transmission electron microscopy suggest that a significant fraction of aperiodic Fe atoms with three Al 1nn are near antiphase domain boundaries.
Complex Formation Equilibria of Some Aromatic β‐Amino‐Alcohols
Authors: Carunchio Vincenzo , Canepari Silvia , Cardarelli Enrico , Pietrodangelo Adriana
Published: April 2004

Complex formation equilibria of some aromatic β‐amino‐alcohols with zinc(II), cadmium(II) and silver(I) have been investigated. The structure of the considered ligands (2‐amino‐1‐phenyl‐1‐propanol, 2‐amino‐3‐phenyl‐1‐propanol and 2‐amino‐1, 3‐propanediol) are similar to some hormones and alcaloids, like adrenaline, noradrenaline and ephedrine, and differ each other for the number and the relative position of alcoholic and phenyl groups. Equilibria constants at 25 °C and μ = 0.5 M (KNO3) have been determined by potentiometric titrations. The comparison of the obtained values with those previously determined for some aliphatic β‐aminoalcohols with the same polar heads has allowed to evidence the influence of aromatic ring on the coordinating properties of ligands, which is different depending on the considered metal ion. In particular, two contrasting effects have been evidenced. The electron withdrawing effect of the aromatic ring causes a decrease of amine basicity, more relevant when phenyl and hydroxylic groups are in 1‐3 position, which reflects in a reduction of metal‐NH2 coordination bond. This effect is predominant in the case of zinc(II) complexes and causes a reduction of complex stability which results directly proportional to the amine group basicity. On the other hand, in the case of silver(I) and cadmium(II) complexes, phenyl group seems to contribute directly to the coordination of the metal ion causing a stabilization of complexes.
Rejuvenating Old Computerized Spectrometric Instrumentation: Discussion of Two Case Histories
Authors: Dossi Carlo , Pozzi Andrea , Recchia Sandro , Giussani Barbara , Dal Santo Vladimiro
Published: April 2004

Computerized analytical instruments of late 70's and 80's are facing rapid technological obsolescence, although they are often retaining good analytical performances. Responsibility is to be attributed to the fast advance in computer technology, which is leaving little or no back‐compatibility with old standards and data formats. Rejuvenation may be reached by simple hardware and software modifications, to allow data exchange with modern PC's and LIMS. Two typical case histories for spectrometric instrumentation of late 70's are then presented and discussed in a general fashion.
Ti and Fe Speciation by X‐Ray Photoelectron Spectroscopy(XPS) and Mössbauer Spectroscopy for a Full Crystal Chemical Characterisation of Ti‐Garnets from Colli Albani (Italy)
Authors: Schingaro Emanuela , Scordari Fernando , Pedrazzi Giuseppe , Malitesta Cosimino
Published: April 2004

Different analytical and structural methods (Electron Probe Micro‐ Analysis, Single Crystal X‐ray diffraction, X‐ray Photoelectron Spectroscopy, Mössbauer spectroscopy) were combined to fully characterise the crystal chemistry of natural Ti‐bearing garnets from Colli Albani (Lazio, Italy). The study of the relevant complex crystal chemistry (large number of cation substitutions affecting the three independent X(8‐fold), Y(6‐fold) and Z(4‐fold) crystallographic sites and Fe and Ti transition elements exhibiting several oxidation states and coordination environments) benefited from the multi‐technique approach.

Electron probe microanalysis provided elemental composition of the analysed samples, which have low Ti‐content (TiO2 in the range 1.99 ‐ 3.48 wt %) and slightly different Fe/Al ratios. For all samples, two doublets were fitted to room temperature Mössbauer spectra and assigned to Fe3+(Y) (∼ 95%) and Fe2+(X) (∼ 5%). Up to three doublets (Ti3+(Y), Ti4+(Y), Ti4+(Z)) were fitted to XPS spectra and yielded direct evaluation of Ti site population. XPS technique confirmed its potential for the study of speciation of Ti in minerals.
Comparison of Different Calibration Methods for the Determination by FT‐NIR Spectroscopy of the Hydroxyl Number in Polyester Resins
Authors: Marengo Emilio , Soave Cristina , Gennaro Maria Carla , Robotti Elisa , Bobba Marco , Lenti Marcello
Published: April 2004

Different calibration methods have been applied for the determination of the Hydroxyl Number in polyester resins, namely Partial Least Squares (PLS), Principal Component Regression (PCR), Ordinary Least Squares with selection of the variables by genetic algorithm (OLS‐GEN) and back‐propagation Artificial Neural Networks (BP‐ANN). The predictive ability of the regression models was estimated by splitting the dataset in training and test sets by application of the Kohonen self‐organising maps. The linear methods (OLS‐GEN, PLS and PCR) showed comparable results while artificial neural networks provided the best results both in fitting and prediction.
Chemical and Environmental Implications of Visible and Near‐Infrared Spectral Features of Salt Crusts Formed from Different Brines
Authors: Howari Fares M.
Published: April 2004

This work describes a laboratory experiment intended to study the formation and spectral reflectance properties of stratified salt crusts that cause severe environmental degradations to soil and water resources in arid regions. Salt crusts were prepared by evaporating three types of saline solutions consisting of i) NaCl ‐ Na2SO4, ii) Na2SO4 ‐ MgSO4, and iii) NaCl ‐ MgSO4 at an initial concentrations of 50 mmol L‐1. They were examined for evaporite mineralogy using X‐ray diffraction, optical and reflected microscopes, and for spectral reflectance with a high‐resolution spectroradiometer (GER 3700) in the visible and near‐infrared regions (400‐2500 nm). The study documented chemical and environmental implications of the spectral properties of salt formed from the studied saline‐systems. The reported results can be used to understand remotely sensed signatures of salt crusts and their implications.
Three‐Stage Sequential Extraction Procedure for Metal Partitioning in Polluted Soils and Sediments
Authors: Elass Khalid , Laachach Abderrahmane , Azzi Mohamed
Published: April 2004

The sequential extraction procedure proposed by the Standard, Measurements and Testing program “SM&T” of the European Union has been applied to evaluate the amounts of Cr, Cu, Mn, Ni, Pb and Zn, extracted at each stage and indirectly their mobility and bioavailability in soil and sediment samples from a polluted area. Analysis of the extracts was carried out by flame atomic absorption spectrometry (FAAS). No significant matrix interferences were found except for Cr in the acetic acid and hydroxylammonium chloride extracts, which required determination by the standard additions method. Both of soils and sediments studied show similar partitioning of Mn, Ni, Cu and Cr. Mn and Ni can be considered to have significant component bound to the acido‐soluble fraction, whereas, Cr and Cu occur largely in the organic and residual phases. The partitioning of Pb and Zn was different between soil and sediment. In terms of mobility and bioavailability, in soils, Ni and Mn can be regarded as moderately available followed by a lower availability of Pb while Cu, Zn and Cr have a very limited availability. In sediments, a higher availability (short‐medium term) of Mn and Zn was presumed followed by a lower availability of Ni and Pb, whereas, Cu and Cr, occurring largely in the organic and residual phases, were of very limited availability.
Extractive Spectrophotometric Determination of Tungsten(VI) Using 3‐Hydroxy‐2‐(2'‐Thienyl)‐4‐OXO‐4H‐1‐ Benzopyran
Authors: Agnihotri Nivedita , Mehta Jaswant R.
Published: April 2004

A simple, rapid, highly sensitive and selective spectrophotometric method for the determination of tungsten(VI) in trace amounts is developed using 3‐ hydroxy‐2‐(2'‐thienyl)‐4‐oxo‐4H‐1‐benzopyran (HTB) as a reagent for the complexation of metal ion and extracting the 1:2 (metal:ligand) complex into dichloromethane from 0.2 M HCl solution. It obeys Beer's law in the range 0‐2.8 μg Wml‐1 with molar absorptivity and Sandell's sensitivity at 415 nm as 6.45 x 104 L mol‐1cm‐1 and 0.0029 μg W(VI) cm‐2, respectively. The method is free from the interference of a large number (39) of elements and handles satisfactorily the analysis of various samples of varying complexity.
The economic efficiency of Irish dairy marketing co‐operatives
Authors: Boyle G.E.
Published: April 2004

This paper is concerned with an empirical test for the economic efficiency of Irish dairy marketing co‐operatives. The paper develops a test for the pricing behavior of dairy marketing co‐operatives based on previous work by R.J. Sexton, B.M. Wilson, and J.J. Wann (1989) and K. Conrad and R. Unger (1987). The proposed test is implemented with data for the Irish dairy‐processing sector. The findings suggest that Irish co‐operatives behaved “as if” they were profit maximizers, and we could find no evidence that this behavior coincided with postulated co‐operative pricing rules. We conclude the paper with a discussion of the economic impact of the EU dairy quota on the Irish dairy‐processing sector. We also discuss the emergence of Public Limited Companies (PLCs) as the dominant organizational structure in the Irish dairy sector. [JEL citations: D21; Q13.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 143–153, 2004.
The forecasting performance of implied volatility from live cattle options contracts: Implications for agribusiness risk management
Authors: Manfredo Mark R. , Sanders Dwight R.
Published: April 2004

This research examines the forecasting performance of implied volatility derived from nearby live cattle options contracts in predicting 1‐week volatility of nearby live cattle futures prices. Forecast evaluation is conducted from the perspective of an agribusiness risk manager. The methodology employed avoids overlapping forecast horizons and focuses on forecast errors, minimizing interpretive issues. Results suggest that implied volatility is a biased and inefficient forecast of 1‐week nearby live cattle futures price volatility. However, implied volatility encompasses all information provided by a time series alternative, and it has improved as a forecast over time. These findings provide insight to agribusiness risk managers on how to adjust for bias and inefficiency of implied volatility, and provide insight into their information content. [JEL/EconLit citations: Q130, Q140, G130.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 217–230, 2004.
Consumer response to functional foods produced by conventional, organic, or genetic manipulation
Authors: Larue Bruno , West Gale E. , Gendron Carole , Lambert Rémy
Published: April 2004

The agro‐food industry is developing a “second generation” of genetically modified (GM) foods that can offer functional health benefits to consumers. Many consumers, however, are turning to organic foods in order to avoid GM foods. This report attempts to differentiate consumer valuation of functional health properties in conventional, organic, and GM foods. A representative sample of 1,008 Canadian household food shoppers responded to twelve stated‐choice experiments during a telephone survey. Because opinions about organic and GM foods varied greatly, random parameters logit models were used to analyze their choices. Results indicate that many Canadian consumers will avoid GM foods, regardless of the presence of functional health properties. For others, the introduction of GM functional plant foods should increase acceptance of GM production methods, but many consumers will likely avoid functional foods derived from GM animals. The organic food industry could also profit from the introduction of organic functional foods. [EconLit citations: I120; D120.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 155–166, 2004.
The determinants of direct mail coupon usage revisited: Evidence from count panel data models
Authors: Chiou‐Wei Song Zan
Published: April 2004

This report employs count panel (as opposed to cross‐sectional) data to empirically investigate the determinants of direct‐mail coupon use. We focus on comparing the coupon use discrepancies between national and store dairy brands. The results do not support the main hypothesis that participants use more coupons the longer they stay in the coupon program. Evidence also shows that prior use significantly explains the coupon‐redemption behavior, while it is found that there are significant expiration date and face value effects. The distance of the consumers from the redemption location is found to be significant. [EconLit citations: C25, J10, and M37.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 189–200, 2004.
Biochemical diagnosis of Antley–Bixler syndrome by steroid analysis
Authors: Shackleton Cedric , Marcos Josep , Malunowicz Ewa M. , Szarras‐Czapnik Maria , Jira Petr , Taylor Norman F. , Murphy Nuala , Crushell Ellen , Gottschalk Michael , Hauffa Berthold , Cragun Deborah L. , Hopkin Robert J. , Adachi Masanori , Arlt Wiebke
Published: April 2004

Antley–Bixler syndrome (ABS, MIM 207410) is a skeletal abnormality syndrome primarily affecting head and limbs. Little is known of the origin of the condition but inactivating mutations in the fibroblast growth factor receptor (FGFR2) has been found in some patients. Genital ambiguity is seen occasionally in this condition, suggesting possible disordered steroidogenesis in early pregnancy. We report the steroid excretion of eight patients diagnosed with the syndrome and one with a related condition, a mild phenotype of the disorder since skeletal and genital abnormalities were not evident. The steroid excretion pattern was consistent and very distinctive in all nine patients. Metabolites of the two primary precursors of steroid hormones, pregnenolone and progesterone, were elevated as were the classical diagnostic metabolites for 17‐ and 21‐hydroxylase deficiencies. Cortisol production was typically within the normal range but generally had blunted response to ACTH. Androgen metabolite excretion tends to be low in patients over 2 months of age, but may be elevated in the newborn period. The metabolome suggested attenuated steroid hydroxylation (including 17,20‐lyase activity) although underlying cause is yet to be established. Mutations in CYP17 and CYP21 have not been found and currently the prime suspect is an abnormality in an essential redox partner (P450 oxidoreductase). This paper proposes use of the distinctive steroid metabolome as the primary biochemical parameter for diagnosis of ABS, at least the form not associated with FGFR2 mutations. © 2004 Wiley‐Liss, Inc.
Prediction of kinetic curves of oxygen consumption on a thermooxidative degradation process for polymer melts
Authors: Kozlov G. V. , Zaikov G. E.
Published: April 2004

The possibility of theoretical prediction of oxygen consumption kinetic curves in a thermooxidative degradation process for polymer melts under conditions that allow for both chemical constitution of polymer and physical structure of melt is shown, the last of which can be quantitatively identified within the framework of fractal analysis. Although obtained for the purposes of predicting kinetic curves, the equation does not contain empirical‐fitting parameters. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3601–3604, 2004
Crystallization and melt behavior of Mg(OH)2/PP composites modified by functionalized polypropylene
Authors: Lin Zhidan , Qiu Yixin , Mai Kanchen
Published: April 2004

The crystallization and melting behavior of Mg(OH)2/PP composites modified by the addition of functionalized polypropylene (FPP) or acrylic acid (AA) and the formation of in situ FPP were investigated by DSC. The results indicated that addition of FPP increased the crystallization temperatures of PP because of the nucleation effect of FPP. The formation of in situ FPP resulted in a reduced crystallization rate, melting point, and degree of crystallization attributed to the decreased regularity of the PP chain. For Mg(OH)2/PP composites, the addition of Mg(OH)2 increased the crystallization temperatures of PP resulting from a heterogeneous nucleation effect of Mg(OH)2. The addition of FPP into Mg(OH)2/PP composites further enhanced the crystallization temperatures of PP. It is suggested that there is an activation of FPP to the heterogeneous nucleation effect on the Mg(OH)2 surface. The addition of AA also increased the crystallization temperatures of PP in Mg(OH)2/PP composites, although the crystallization temperature of PP was not influenced by the AA content, which is explained by the heterogeneous nucleation effect of the Mg(OH)2 surface activated by FPP and AA. A synergistic effect on the crystallization of PP in Mg(OH)2/PP composites further increased the crystallization temperatures of PP. However, The crystallization temperatures of Mg(OH)2/PP composites modified by in situ FPP were lower than those of Mg(OH)2/PP composites modified by addition of either FPP or AA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3610–3621, 2004
Graft copolymerization of nitrile monomers onto bleached jute fiber using potassium persulfate system and their textile characteristics
Authors: Mondal Md. Ibrahim H. , Alam Rashidul , Sayeed Md. Abu
Published: April 2004

Graft copolymerization of nitrile monomers, such as acrylonitrile and methacrylonitrile, onto bleached jute fiber was carried out by using K2S2O8/FeSO4 redox system in nitrogen atmosphere and their effect on the textile characteristics was also investigated. Percent graft yield increased with the increase of concentrations of monomer, initiator, and catalyst, reaction time, and reaction temperature up to a certain value, and, thereafter, it decreased. The effect of percent grafting efficiency was similar to that of percent graft yield, except for the monomer concentration. The increase of percent graft yield was dependent on the availability of jute‐macroradicals as well as monomer radicals. Sometimes the predominancy of homopolymerization over grafting and the premature termination of growing grafted chains occurred because of the higher monomer radicals and excess primary radicals, SO4−• and •OH, from K2S2O8 initiator. The percent graft yield of acrylonitrile and methacrylonitrile was 20.5 and 29.1%, respectively. Higher graft yield for methacrylonitrile might be due to the methyl group present in it. Infrared spectra at 2229–2235 cm−1 of acrylonitrile‐ and methacrylonitrile‐grafted jute strongly supported the graft formation. Grafting of jute fiber improved the thermal stability, protected from photooxidative degradation, and decreased swellability as well as dyeability, etc. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3622–3629, 2004
Bending‐electrostrictive response of polyurethane films subjected to a reversed electric field
Authors: Watanabe Masashi , Hirai Toshihiro
Published: April 2004

This study dealt with the bending‐electrostrictive response of a polyurethane film, which was a promising candidate for a material to be used in polymer actuators. The film bent under an electric field (2.5 MV/m). However, when the field polarity was reversed, the bending direction curiously did not change. To clarify the mechanism of this behavior, we measured the space charge distribution in the film. The measurement showed a pair of charges (induced charge on an electrode and space charge in the film) on one side of the film during the application of the field. However, when the field polarity was reversed, the location of the charges did not change. The charges were assumed to be the cause of the bending. Therefore, we concluded that the bending direction did not change despite the reversed field because the location of the charges did not change. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3644–3650, 2004
Preparation and swelling characterization of poly (n‐isopropylacrylamide)‐based porous hydrogels
Authors: Chern Jia‐Ming , Lee Wen‐Fu , Hsieh Meng‐Yow
Published: April 2004

Nine different poly(n‐isopropylacrylamide)‐based hydrogels, including nonionic, cationic, and anionic hydrogels, were synthesized in with and without the addition of pore‐forming agents. The synthesized hydrogels were characterized with dry gel density measurements, scanning electron microscopy observations, and the determination of the swelling ratio swelling kinetics. All the results showed that the cationic hydrogels had faster swelling kinetics than the anionic and nonionic hydrogels. The addition of pore‐forming agents (NaHCO3 and carboxymethylcellulose) during the synthesis process led to porous hydrogels with lower dry densities, swelling ratios, and swelling kinetic parameter values. An empirical equation was developed to successfully correlate the swelling kinetic parameter with the hydrogel swelling ratio. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3651–3658, 2004
Comparison of maleic anhydride grafting onto powder and granular polypropylene in the melt by reactive extrusion
Authors: Güldoğan Yılser , Eğri Sinan , Rzaev Zakir M. O. , Pişkin Erhan
Published: April 2004

The grafting of powder and granular polypropylene (PP) with maleic anhydride (MA) was investigated in a reactive extrusion process with dicumyl peroxide (DCP) as an initiator. The effects of the MA and DCP contents in the feed on grafting were investigated. Under the experimental conditions applied in this study, the grafted monomer unit content was varied from 0.023 to 0.5%. The MA grafting efficiency of powder PP was higher than that obtained for the granular form of PP. In general, the grafting degree first increased with the MA or DCP content in the feed, then reached a maximum value, and finally decreased because of several possible alternative reactions during the grafting. The grafting of powder PP was more successful because of better initial mixing and less diffusional resistance during the grafting. An increase in the MA content in the feed caused significant reductions in the melt‐flow index of the graft copolymers. The results obtained with Fourier transform infrared, differential scanning calorimetry, and X‐ray powder diffraction analyses indicated that the structure, macrotacticity, crystallinity, crystallization, and thermal behavior of PP changed with grafting and depended on the grafting degree. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3675–3684, 2004
Thermal stability of polycaprolactone/Nafion blends prepared in the presence of 3‐aminopropyltriethoxysilane
Authors: Cassu Silvana Navarro , Zoppi Rita Aparecida , Felisberti Maria Isabel
Published: April 2004

Polycaprolactone (PCL) and Nafion blends were prepared in the presence of 3‐aminopropyltriethoxysilane (3‐APTEOS) by a sol–gel reaction. The presence of 3‐APTEOS allowed the preparation of macroscopically homogeneous self‐supported films of PCL/Nafion blends in a wider composition range. The thermal properties of the blends were evaluated by thermogravimetric analysis and differential scanning calorimetry. The thermal stability of the blends decreased as the Nafion content increased. The reduction of the thermal stability of PCL in the presence of Nafion was confirmed with Fourier transform infrared/photoacoustic spectroscopy, and it was attributed to the possible hydrolysis of PCL caused by the reaction with the SO3H acid groups of Nafion. An opposite effect on the thermal stability of the blends was caused by the addition of 3‐APTEOS. The increase in the thermal stability of the blends with the increase in the 3‐APTEOS content was assigned to the neutralization of the acid groups of Nafion by the formation of an ionic complex. The differential scanning calorimetry results showed that PCL and Nafion were immiscible. The degree of crystallinity of PCL slightly increased with an increase in the Nafion content, whereas the melting temperature remained basically unchanged. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3701–3709, 2004
Effect of radiation dose on the thermal degradation of poly(ethylene terephthalate) fabric
Authors: El‐Gendy E. H. , El‐Shanshoury I. A.
Published: April 2004

The effect of radiation dose (10–30 kGy) on the thermal decomposition of poly(ethylene terephthalate) was studied using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and X‐ray diffraction (XRD) analysis. The TGA and DSC were carried out in a flowing nitrogen atmosphere at heating rates of 5 and 30°C/min for TGA and 10°C/min for DSC. The degradation process was composed of three overlapping stages. The second stage, at which a rapid degradation occurs, was studied in detail. The process was found to follow a second‐order kinetics and was independent of radiation dose or heating rate. The reaction rate constant (k) was found to depend on the heating rate and iradiation dose. The apparent activation energy (Q) and the logarithm of the preexponential rate constant (log A) were found to decrease linearly with the increase in dose at rates of 3.32 kJ mol−1 kGy−1 and 0.177 s−1 kGy−1 with intercepts of 249 kJ/mol and 12.26 s−1 for Q and log A of unirradiated fabric, respectively. A direct relationship was found between the percentage decrease in Q and log A and the percentage decrease in the temperature corresponding to 50% conversion (T50%) for samples irradiated at different doses. It was found that a decrease in T50% by 1% resulted in a decrease in Q and log A by 1.855 and 2.1%, respectively. Changes in Q and log A resulting from radiation, mechanical and thermal treatments, or their combinations can be predicted from the shift in T50%. The history of the fibers substantially affected the thermal properties. DSC and XRD studies revealed changes in the fabric crystallinity. DSC measurements indicated a linear increase in heat of fusion with dose increase at a rate of 0.855 kJ kg−1 kGy−1. XRD analysis confirmed structural changes, rearrangement by plane rotations, and formation of compact crystalline lattice with patterns characterizing irradiated samples. An attempt to explain the dependency of the apparent activation energy on dose was given. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3710–3720, 2004
Synthesis of a polyacrylamidoxime chelating fiber and its efficiency in the retention of palladium ions
Authors: Bilba Nicolae , Bilba Doina , Moroi Gabriela
Published: April 2004

A chelating fibrous polymer with metal complexing ability was prepared by partial conversion of the nitrile groups of melana (an acrylonitrile‐based synthetic fiber) into amidoxime groups C(NH2) = NOH using a solution of 3% hydroxylamine in methanol by refluxing at 80°C. The molar ratio of NH2OH/CN and the reaction time were adjusted to values of 0.9 and 2 h, respectively. The amidoximated polyacrylonitrile fiber with a 2.89 meq/g ion‐exchange capacity functions as an efficient chelating adsorbent for palladium ions. The pH dependence, the contact time, and the temperature of palladium ion retention from a model solution on amidoximated acrylic fiber were studied. The fibrous chelating adsorbent exhibited high affinity for palladium ions in acidic solution (pH = 2–6) at high temperature (50–60°C). The values of parametersqmandKL(from the Langmuir equation) determined at different temperatures of adsorption and the thermodynamic quantities ΔG, ΔH,and ΔSwere calculated. The adsorbed palladium ions can be quantitatively desorbed by elution with a 0.3% hydrochloric solution of thiourea. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3730–3735, 2004
Influence of quaternary ammonium salt addition on the surface activity of polyacrylic dispersants
Authors: Pantchev I. , Hunkeler D. J.
Published: April 2004

A variety of poly(alkyl methacrylate‐co‐acrylic acid) (PS) copolymers were synthesized under conditions resembling those used in industrial processes. The interfacial tension dependence on the composition, the concentration of the polymers, and the presence of water‐soluble quaternary ammonium salt (octadecyltrimethylammonium chloride) were investigated. The studies reveal that the presence of a quaternary ammonium salt decreases the interfacial tension to a high degree and improves the dispersing properties of the synthesized copolymers. Some examples of using PS copolymer with 15 mol % acrylic acid content as a dispersant in inverse suspension copolymerization process of acrylamide and acrylic acid are presented. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3736–3743, 2004
Thermal and flow property–morphology relationship of sugarcane bagasse fiber‐filled polyamide 6 blends
Authors: Dweiri R. , Azhari C. H.
Published: April 2004

The structure–property relationship of sugarcane bagasse fiber‐filled polyamide 6 blends at different blend compositions has been investigated. Blends were prepared in the composition of wt % PA6/wt % bagasse as follows: 98/2, 95/5, and 90/10 for three fiber length ranges (<100, <250, and <500 μm) using a twin‐screw extruder. Thermal properties were evaluated by measuring the glass transition temperature Tg, enthalpy of fusion ΔHf, crystallinity Xc and thermogravimetry, TG. Results showed that Tg of the composites changed with change in fiber loading and length. The Xc as well as ΔHf of the blends reduced to almost half its value for the neat PA6. The thermogravimetric curves TG showed that the thermal stability of the composites was lower than that of the neat PA6. Rheological properties were studied as a function of fiber loading, fiber length, shear rate, and temperature. The viscosity of composites increased with increasing fiber loading and length at low shear rates but decreased below that of neat PA6 at high shear rates. It was also found to be temperature sensitive, and influenced by fiber lengths particularly at higher temperatures. The morphology of the blends was studied using a Leica laser scanning confocal microscopy at two different regions: at the wall, and the core. The micrographs of the blends showed that fibers present in the form of bundles were found at the wall of the extrudates and increased in volume with increase in both length and concentration, at the same temperature and shear stress. In the core region, there is laminar flow, presenting striation morphology, with the omnipresent bundles of fibers dispersed in the matrix. At higher shear rates, the bundles were pushed to the wall. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3744–3754, 2004
The diffusion of gases in semicrystalline polyethylene and its melt
Authors: Kozlov G. V. , Zaikov G. E.
Published: April 2004

The fractal analysis and the cluster model of the polymer amorphous structure make it possible to account for a change in the diffusion coefficient in polyethylene both above and below the melting temperature. The proposed interpretation explains the diffusivity jump at the melting point as resulting from the disintegration of local‐order regions. The formation of these regions is due to polyethylene crystallization. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3761–3763, 2004
Successful reproduction of the introduced slider turtle (Trachemys scripta elegans) in the South of France
Authors: Cadi Antoine , Delmas Virginie , Prévot‐Julliard Anne‐Caroline , Joly Pierre , Pieau Claude , Girondot Marc
Published: April 2004

Massive importation of slider turtles (Trachemys scripta elegans) as a pet in France over the past few decades has been followed by the release of many of these turtles into natural environments. T. scripta elegans is now widely distributed in France.

This paper reports on the successful reproduction of this species in France, with confirmed production of both sexes from nests incubated in the wild. These results indicate that the turtle T. scripta elegans can reproduce in the wild and that its long‐term persistence is possible in France.

The potential impact of this invasive species in natural ecosystems warrants future study. Meanwhile, authorities are strongly encouraged to educate the public to the potential danger of exotic species introduction for local ecosystems and to capture and remove this species from wetlands in southern Europe.

Copyright © 2004 John Wiley & Sons, Ltd.
Effects of flow variation on channel and floodplain biota and habitats of the Sacramento River, California, USA
Authors: Sommer Ted R. , Harrell William C. , Solger Anke Mueller , Tom Brad , Kimmerer Wim
Published: April 2004

Despite progress in the development of conceptual models of river processes, the validation and application of these models to conservation may be limited by a deficit of tools for intermediate‐scale (1–100km) reaches. A model was developed to examine the effect of variation in flow on the responses of two trophic levels in a large temperate river (Sacramento River) and its seasonal floodplain (Yolo Bypass). Field data and hydrologic simulations were evaluated for three hydrologically diverse years.

The simulations showed much more hydrologic variability in the floodplain than the river, with greater total surface and shallow area, longer hydraulic residence times, and lower water velocities for the floodplain.

Chlorophyll a levels were significantly higher in the floodplain than in the river, and were negatively associated with flow. These results were consistent with longer hydraulic residence times, increased surface area of shallow water, and warmer water temperatures.

Copepods and cladoceran densities were similar in the river and its floodplain, and were mostly negatively associated with flow.

There were significantly higher densities of Diptera and terrestrial invertebrates in the floodplain than the river. Diptera densities in the floodplain were positively associated with flow.

These results provide evidence of the incremental value of floodplain habitat to the conservation of large rivers. In particular, it appears that providing river–floodplain connectivity can enhance production of lower trophic levels at relatively rapid time scales, probably benefitting secondary consumers, including Chinook salmon (Onchyrhynchus tshawytscha).

Copyright © 2004 John Wiley & Sons, Ltd.
Disruption of transforming growth factor β signaling and profibrotic responses in normal skin fibroblasts by peroxisome proliferator–activated receptor γ
Authors: Ghosh Asish K. , Bhattacharyya Swati , Lakos Gabriella , Chen Shu‐Jen , Mori Yasuji , Varga John
Published: April 2004

Objective

In fibroblasts, transforming growth factor β (TGFβ) stimulates collagen synthesis and myofibroblast transdifferentiation through the Smad intracellular signal transduction pathway. TGFβ‐mediated fibroblast activation is the hallmark of scleroderma and related fibrotic conditions, and disrupting the intracellular TGFβ/Smad signaling may provide a novel approach to controlling fibrosis. Because of its potential role in modulating inflammatory and fibrotic responses, we examined the expression of the nuclear hormone receptor peroxisome proliferator–activated receptor γ (PPARγ) in normal skin fibroblasts and its effect on TGFβ‐induced cellular responses.

Methods

The expression and activity of PPARγ in normal dermal fibroblasts were examined by Northern and Western blot analyses, immunocytochemistry, flow cytometry, and transient transfections with reporter constructs. The same approaches were used to evaluate the effects of PPARγ activation by naturally occurring and synthetic ligands on collagen synthesis and α‐smooth muscle actin (α‐SMA) expression. Modulation of Smad‐mediated transcriptional responses was examined by transient transfection assays using wild‐type and dominant‐negative PPARγ expression constructs.

Results

The PPARγ receptor was expressed and fully functional in quiescent normal skin fibroblasts. Whereas ligand activation of cellular PPARγ resulted in modest suppression of basal collagen gene expression, it abrogated TGFβ‐induced stimulation in a concentration‐dependent manner. This response was mimicked by overexpressing PPARγ in fibroblasts, and was blocked by a selective antagonist of PPARγ signaling or by transfection of fibroblasts with dominant‐negative PPARγ constructs. Furthermore, PPARγ ligands abrogated TGFβ‐induced expression of α‐SMA, a marker of myofibroblasts. Stimulation of Smad‐dependent transcriptional responses by TGFβ was suppressed by PPARγ despite the absence of a consensus PPARγ‐response element in the targeted promoters. Ligand‐induced activation of fibroblast PPARγ had no effect on protein expression of cellular Smad3 or Smad7.

Conclusion

By abrogating of TGFβ‐induced stimulation of collagen gene expression, myofibroblast transdifferentiation, and Smad‐dependent promoter activity in normal fibroblasts, PPARγ may play a physiologic role in the regulation of the profibrotic response. Furthermore, our results suggest that PPARγ activation by pharmacologic agonists may represent a novel approach to the control of fibrosis in scleroderma.
The prevalence, onset, and clinical significance of antiphospholipid antibodies prior to diagnosis of systemic lupus erythematosus
Authors: McClain Micah T. , Arbuckle Melissa R. , Heinlen Latisha D. , Dennis Gregory J. , Roebuck Jon , Rubertone Mark V. , Harley John B. , James Judith A.
Published: April 2004

Objective

To determine whether antiphospholipid antibodies (aPL) occur before the diagnosis of systemic lupus erythematosus (SLE) and before initial clotting events, and whether their presence early in the disease course influences clinical outcome.

Methods

Serum samples obtained from 130 lupus patients before and after SLE diagnosis were screened for IgG and IgM aPL using an anticardiolipin (aCL) enzyme‐linked immunosorbent assay. Medical records of all patients were carefully reviewed for data on the time of onset of SLE features meeting clinical criteria and on disease manifestations.

Results

Twenty‐four patients (18.5%) were positive for IgG and/or IgM aCL prior to SLE diagnosis. Anticardiolipin antibodies appeared from 7.6 years prior to SLE diagnosis to within the same month as SLE diagnosis, with a mean onset occurring 3.0 years before SLE diagnosis. Additionally, aCL presence early in the disease process seemed to predict a more severe clinical outcome; these patients eventually met an average of 6.1 of the 11 classification criteria for SLE, compared with 4.9 criteria for other patients (P < 0.001). The early aCL‐positive population also had more frequent renal disease, central nervous system disease, thrombocytopenia, and clotting events. In this population, aCL preceded initial thrombotic events by a mean of 3.1 years.

Conclusion

Anticardiolipin antibodies in SLE patients tend to precede initial clotting events by several years. Furthermore, the presence of early, prediagnosis aPL seems to herald a more varied, severe clinical course with earlier onset in patients with SLE.