bluuebunny/crossref_metadata_2025 huggingface dataset:
Rural business use of information and communications technologies (ICTs): a study of the relative impact of collective activity in rural Scotland
Authors: Deakins David , Mochrie Robbie , Galloway Laura
Published: June 2004

There has been limited systematic or comprehensive research on the use and impact of ICTs on rural small and medium size firms (SMEs), yet the use and take‐up of ICTs has been highlighted as an important strategic factor in the development of both rural firms and rural communities by a number of studies. Indeed, several empirical studies have found that rates of ICT adoption in SMEs lag behind those in larger businesses. This investigates the extent to which this can be seen to be the case in rural Scotland, and investigates the use of ICTs in rural firms.

A review of the literature is undertaken and relevant recent policy developments considered. Quantitative data is used to determine the rate and extent of ICT take‐up in rural SMEs. Using both quantitative and qualitative methods, attempts are made to examine a novel support mechanism — the Internet forum — based on rural locality or rural locality‐specific industry.

Contrary to previous literature, the survey evidence suggests that ICT use in business is high by small firms in rural areas, including utilizing on‐line sources for markets and suppliers. Internet forums appear to be significant for utilizing ICT‐related technologies for business growth, especially for increasing sales and accessing international markets. Internet forums may also have encouraged relatively high use of public sector sources of advice and support.

Qualitative findings show that Internet business forums exist due to complicated reasons that are more related to local and individual human factors rather than market forces. That is, they have often arisen where local communities or local individuals have been able to raise funding, or where they have been the target of public sector initiatives and funding.

This paper supports the view that the establishment of Internet‐based business forums can have beneficial advantages for local rural firms. However, it is recognized that where such forums exist it is likely that it is the more growth‐orientated firms that will join them and that strategies for sustainability of forums, while desirable, were not observed.

Copyright © 2004 John Wiley & Sons, Ltd.
Quantification of major lipid classes in human triacylglycerol‐rich lipoproteins by high‐performance liquid chromatography with evaporative light‐scattering detection
Authors: Perona Javier S. , Ruiz‐Gutierrez Valentina
Published: June 2004

Triacylglycerol‐rich lipoproteins (TRL), comprising chylomicrons (CM) and very‐low‐density lipoproteins (VLDL), have been associated with cardiovascular disease. The lipid class content in the remnant particles of these lipoproteins is a determinant for the accumulation of lipids in macrophages and their transformation into foam cells. We have optimized a method for the simultaneous determination of cholesteryl esters (CE), triacylglycerols (TG), free cholesterol (FC), monoacylglycerols (MG), and phospholipids (PL) by HPLC coupled to a light‐scattering detector (ELSD). A diol column and a ternary gradient of hexane, 2‐propanol, and methanol were applied to CM and VLDL of human origin (n = 10), with excellent precision in terms of repeatability of peak areas and retention times. All peaks were baseline resolved although the resolution of CE and TG was compromised for the sake of simplicity of the solvent gradient. The ELSD response was fitted to second‐order equations, with correlation coefficients (r 2) higher than 0.999 for a wide range of concentrations (0.25–10 μg of lipid injected). TG were the major lipid class detected in human TRL, accounting for 62% in CM obtained 2 h after the oil intake. In addition we recorded a depletion of TG and CE in CM obtained 2 h after the oil intake of about 60%. We conclude that the method reported here is suitable for a rapid and precise determination of lipid classes in human TRL and, therefore, may be a useful tool for investigations on the atherogenicity of these lipoproteins.
Determination of hydrolyzable tannins in the fruit of Terminalia chebula Retz. by high‐performance liquid chromatography and capillary electrophoresis
Authors: Juang Lih‐Jeng , Sheu Shuenn‐Jyi , Lin Ta‐Chen
Published: June 2004

A RP‐HPLC method for determining fourteen components (gallic acid, chebulic acid, 1,6‐di‐O‐galloyl‐D‐glucose, punicalagin, 3,4,6‐tri‐O‐galloyl‐D‐glucose, casuarinin, chebulanin, corilagin, neochebulinic acid, terchebulin, ellagic acid, chebulagic acid, chebulinic acid, and 1,2,3,4,6‐penta‐O‐galloyl‐D‐glucose) in the fruit of Terminalia chebula Retz. is described. The separation was achieved within 80 min using a binary gradient with mobile phases consisting of a pH 2.7 phosphoric acid solution and an 80% CH3CN solution. Capillary electrophoretic analyses were also attempted, and it was found that CZE (25 mM Na2B4O7, 5 mM NaH2PO4, pH 7.0) was an efficient method for the separation of gallotannins, while an MEKC method (25 mM Na2B4O7, 5 mM NaH2PO4, 20 mM SDS, pH 7.0, and 10% acetonitrile) provided a better separation for most of the tannins examined. The HPLC and CE methods developed were both successfully applied to the assay of tannins in commercial samples of Chebulae Fructus.
On the potential of electrochemically modulated liquid chromatography of proteins in a micro open parallel plate separator
Authors: Lapizco‐Encinas Blanca H. , Pinto Neville G.
Published: June 2004

Electrochemically Modulated Liquid Chromatography (EMLC) is a technique in which an electrical potential is applied to the stationary phase in order to alter its adsorptive properties. The micro Open Parallel Plate Separator (μOPPS) is an open‐channel micro‐chromatographic system with the unique characteristic of an adjustable rectangular flow cross‐section. In this publication, the performance of the μOPPS in the EMLC mode was simulated using a comprehensive mathematical model. The separation of two proteins was analyzed by performing a parametric study for the effects of the potential applied to the stationary phase, the dimensions of the device, and the operating conditions. It is shown that the combination of the μOPPS and EMLC is promising for protein separations. These separations can be optimized by carefully selecting the applied potential and the geometry of the μOPPS. The marriage of the μOPPS and EMLC adds two additional dimensions for control, to improve the separation efficiency in analytical applications and in preparative separations of trace compounds.
Good or bad rangeland? Hybrid knowledge, science, and local understandings of vegetation dynamics in the Kalahari
Authors: Thomas D. S. G. , Twyman C.
Published: June 2004

Using data from field studies in the Kalahari rangelands of Southern Africa, the relationships between ‘scientific’ and ‘land user’ interpretations of land degradation and change in nonequilibrium savanna ecosystems are explored. Scientific and land‐user views are often regarded as distinct, and even opposed, knowledges. We contest that a more constructive view can be taken through the concept of hybrid knowledge, whereby value is attached to both approaches and through which a more useful and meaningful assessment of environmental change, and its implications for development and natural resource use, can be made. We find that in both the southwestern and northwestern Kalahari, pastoralists have a complex understanding of the patchiness of ecosystem variability, and that they utilise elements of this patchiness of change, notably dimensions of bush encroachment and grass species change that have commonly been regarded as degradation in scientific understandings, within livestock management strategies, especially at times of environmental stress. We urge caution in the application of the termdegradation, and a more widespread recognition of the multifaceted dimensions, including benefits, ofchangewithin the scientifically recognized variability of nonequilibrium rangelands. Copyright © 2004 John Wiley & Sons, Ltd.
Kalahari sand soils: spatial heterogeneity, biological soil crusts and land degradation
Authors: Dougill A. J. , Thomas A. D.
Published: June 2004

This paper identifies spatial associations between surface nutrients, biological soil crusts and vegetation in the Kalahari. Four locations, with different land use and substrate characteristics were used to determine the extent of biological crust cover and the factors affecting the spatial heterogeneity in soil nutrients and ecology. Despite the sandy texture of Kalahari soils and regular surface disturbances, there is a significant biological soil crust cover (19–40%) at all locations. This is due to a combination of resistance to trampling, sub‐canopy niches protected from disturbance and the prevalence ofMicrocoleus vaginatuscyanobacteria, which are able to rapidly reform crusts. Crust cover and diversity is enhanced on ironstone and calcrete soils. The spatial variability of soil nutrients is low but is increased by grazing‐induced bush encroachment. The preferential development of nitrogen‐fixing biological soil crusts under bushes could enhance the competitive advantage ofAcacia melliferafavouring further bush encroachment. Whether this constitutes land degradation is dependent upon the extent to which sub‐bush canopy niches retain palatable grass species. Copyright © 2004 John Wiley & Sons, Ltd.
Demographic dynamics and land degradation at Ratau, Lesotho, in the context of rural sustainability
Authors: Makhanya E. M.
Published: June 2004

Population trends and factors have been identified as indicators of sustainability. Existing plans for sustainable development have generally recognized demographic trends and factors as elements that have a critical influence on consumption patterns, production, lifestyles and long‐term sustainability. The aim of this study, which was carried out at Ratau in Lesotho, was to examine the relationship between demographic dynamics and environmental degradation. The objective was to identify the nature and extent of the relationships between the prevailing land degradation and demographic factors at Ratau, and thereby appraise its sustainability. It was found that Ratau was overpopulated, overgrazed, underdeveloped and degraded. It was further established that there is some linkages between material poverty of the villagers, poor agricultural‐land management and environmental degradation, which indicates an adverse synergistic relationship between demographic dynamics and sustainable rural development in the study area. Copyright © 2004 John Wiley & Sons, Ltd.
Education and land‐use planning for sustainable agricultural development in Western Australia
Authors: Conacher A. , Tonts M. , Conacher J.
Published: June 2004

Land degradation associated with agriculture has been recognized worldwide as posing serious environmental, natural resource and human problems. As a consequence, the Australian Government agricultural agencies, while still focusing on agricultural development, are increasingly being required to add social and biophysical environmental objectives to their more traditional economic development roles. One of the difficulties faced by agencies in achieving this aim is the lack of appropriate skills by their traditionally educated professional staff.

This paper shows how one such agency, the Western Australian Department of Agriculture, is responding to major land degradation problems and the need to undertake integrated land‐use planning to achieve sustainable development objectives. In particular, following a tender process whereby the authors provided advice on alternative means of achieving the agency's objectives, the authors were contracted through the University of Western Australia's Institute for Regional Development to mount an on‐line course designed for agency officers.

While students have responded positively to the course content, a number of problems relating to the delivery of this course has emerged. They include the feeling of isolation by the students, problems with web designer over educational philosophies, the inordinate amount of time involved in writing and delivering the course, and unresolved questions relating to intellectual property. The question still remains as to whether the course will achieve the primary underlying objective of attaining sustainable agricultural development. Copyright © 2004 John Wiley & Sons, Ltd.
Technological change in agriculture and land degradation in Bangladesh: a case study
Authors: Ali A. M. S.
Published: June 2004

Much of Bangladesh has experienced land degradation due to technological change in agriculture in an attempt to increase food production. This study examines the impacts of cultivation of high‐yielding variety (HYV) rice, using power tillers, low‐lift irrigation pumps, chemical fertilizers and pesticides, on selected land and soil qualities during the period 1985–2000 in a village in southwestern Bangladesh. For the purpose, three types of land uses were identified: fields traditionally plowed to cultivate rain‐fed localamanrice using cow‐manure and very little or no pesticides; plots power tilled to cultivate rain‐fed HYVamanrice using full‐dose application of chemical fertilizers and pesticides; and fields power tilled to cultivate rain‐fed HYVamanrice followed by low‐lift pump irrigated HYVbororice using double doses of chemical fertilizers and pesticides. Based on 120 soil samples collected from 60 plots representing these three land‐use types, the present study revealed significant changes in soil texture, bulk density and structure, increases in soil acidity and salinity, depletion of Ca, Mg, K, N, P, Zn, and organic C in double‐cropped irrigated rice fields compared to the rain‐fed single‐crop rice fields. Power‐tilled plots have shown higher rate of soil erosion and loss of soil structure than traditionally plowed fields. Low‐lift pump irrigated fields were more degraded than rain‐fed rice fields. Soil degradation has affected the yield of rice while cultivation of HYV rice has decreased the fodder production that affected livestock population. While technological change was necessary to meet the growing population demand for food, its negative impacts on land and soil qualities are alarming and should be minimized by adopting more sustainable techno‐managerial methods and continuous soil monitoring. Copyright © 2004 John Wiley & Sons, Ltd.
Keeping score on community investment
Authors: Kaplan Robert S. , Norton David P.
Published: June 2004

The same standards should apply to community investments that apply elsewhere in business.
The employee care revolution
Authors: Argenti Paul A. , Forman Janis
Published: June 2004

Developing effective employee communication strategies.
Polymerization of Methyl Methacrylate with Chloro Zirconocene Enolates
Authors: Ferenz Michael , Bandermann Friedhelm , Sustmann Reiner , Sicking Willi
Published: June 2004

Summary: The polymerization of methyl methacrylate (MMA) in the presence of the neutral chloro zirconocene enolates, Cp2ZrCl[OC(OMe)CMe2] (1), Me4C2(Cp)2ZrCl[OC(OMe)CMe2] (2), and Me2C(Cp)2ZrCl[OC(OMe)CMe2] (3), was investigated. None of these compounds is catalytically active on its own. They could be activated by adding Ph3CB(C6F5)4 (4); however, only if the initial concentration of enolate is higher than that of the perfluorated phenyl borate. Polymers were produced with a number average molar mass of up to 100 000 g/mol and a dispersion index of 1.1–1.3 with mixtures comprising 1 and 4 or 2 and 4. The degree of polymerization depends only on the quantity of excess enolate and not on the absolute concentration of the initiator components. In contrast, a mixture of 3 and 4 was not very active. Kinetic modeling of the systems as well as NMR spectroscopic investigations indicate that a bimetallic mechanism can describe chain growth. The activity of these catalytic systems depends on the structure of the ligand. The two zirconocenes with bridged cyclopentadienyl ligands, (2) and (3), convert MMA considerably slower. In addition to the methyl zirconocene enolates with unbridged cyclopentadienyl ligands, the corresponding chloro zirconocene enolates are also suitable for the polymerization of MMA. The latter compounds offer the advantage that preparations for the production of the initiators are comparatively simple.

Structures of investigated initiators.

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Structures of investigated initiators.
A New Versatile Radical Addition on α, ω‐Dimethacrylate Poly(ethylene oxide)
Authors: Jarroux Nathalie , Guégan Philippe , Buchmann William , Tortajada Jeanine , Cheradame Hervé
Published: June 2004

Summary: The synthesis of α,ω‐di(2‐methyl‐6‐pyrenyl‐2‐succinimidylhexanoic ester)poly(ethylene oxide) (Py(S)‐EOn‐(S)Py) was obtained by a new radical reaction between 4‐pyrenylbutanoate N‐hydroxysuccinimidyl ester and α,ω‐dimethacrylate poly(ethylene oxide). The reason for the choice of such bulky groups is a possible application of this reaction to the synthesis of polyrotaxane from polypseudorotaxane. Two reaction media were examined, heterogeneous in water at room temperature using persulfate as initiator, or homogeneous in DMSO at 60 °C using AIBN as initiator. Structural characterization of the functionalization products was carried out by SEC, MALDI TOF, and NMR spectroscopies. It was shown that two types of α,ω‐dipyrenyl PEO could be obtained, one corresponding to the expected product (Py(S)‐EOn‐(S)Py), the other corresponding to the same structure but without the succinimidyl substituent (Py(H)‐EOn‐(H)Py). It was also shown that in the soluble system macrocycles could be formed and this last aspect has been assigned to intramolecular interactions existing between the pyrenyl groups. An interesting aspect of this synthesis is the possibility to find conditions giving high yields without crosslinking and fairly reduced amount of coupling.

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Ring Opening Metathesis Polymerization (ROMP) of cis‐ and trans‐3,4‐Bis(acetyloxymethyl)cyclobut‐1‐enes and Synthesis of Block Copolymers
Authors: Lapinte Vincent , de Frémont Pierre , Montembault Véronique , Fontaine Laurent
Published: June 2004

Summary: The synthesis and living ring opening metathesis polymerization (ROMP) of diacetate functionalized cyclobutene derivatives cis‐3,4‐bis(acetyloxymethyl)cyclobutene (2) and trans‐3,4‐bis(acetyloxymethyl)cyclobutene (3) were investigated with the functional group tolerant initiators (PCy3)2(Cl)2RuCHPh (I) and (SIMes)(PCy3)(Cl)2RuCHPh (II) (SIMes: 1,3‐dimesityl‐4,5‐dihydroimidazol‐2‐ylidene). The kinetic parameters of the ROMP initiated by the ruthenium alkylidene complexes I and II were determined and correlated to monomer stereochemistry. The cis isomer 2 was found to be more reactive than the trans isomer 3 and to generate functional polymers of narrow molecular weight distribution especially with the classical “first generation Grubbs catalyst” I. Block copolymers containing 2 and cyclooctadiene (COD) or norbornene (NBE) were synthesized. Block copolymer poly(2‐b‐COD) was hydrolyzed and converted to a material with a block bearing hydrophilic alcohol functional groups and hydrophobic block.

SEC elution profiles: poly(2) prepolymer and block copolymer poly(2‐b‐COD).

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SEC elution profiles: poly(2) prepolymer and block copolymer poly(2‐b‐COD).
On the coefficients of concave univalent functions
Authors: Avkhadiev Farit G. , Pommerenke Christian , Wirths Karl‐Joachim
Published: June 2004

Let D denote the open unit disc and f : D → \documentclass{article} \usepackage{amssymb} \pagestyle{empty} \begin{document} $ \overline {\mathbb C} $ \end{document} be meromorphic and injective in D. We assume that f is holomorphic at zero and has the expansion

Especially, we consider f that map D onto a domain whose complement with respect to \documentclass{article} \usepackage{amssymb} \pagestyle{empty} \begin{document} $ \overline {\mathbb C} $ \end{document} is convex. We call these functions concave univalent functions and denote the set of these functions by Co.

We prove that the sharp inequalities |an| ≥ 1, n ∈ ℕ, are valid for all concave univalent functions. Furthermore, we consider those concave univalent functions which have their pole at a point p ∈ (0, 1) and determine the precise domain of variability for the coefficients a2 and a3 for these classes of functions. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A non‐commutative Landau‐Zener formula
Authors: Fermanian Kammerer Clotilde
Published: June 2004

We study semi‐classical measures of families of solutions to a 2 × 2 Dirac system with 0 mass, which presents bands crossing. We focus on constant electro‐magnetic fields. The fact that these fields are orthogonal or not leads to different geometric situations. In the first case, one reduces to some well‐understood model problem. For studying the second case, we introduce some two‐scale semi‐classical measures associated with symplectic submanifold. These measures are operator‐valued measures and the transfer of energy at the crossing is described by a non‐commutative Landau‐Zener formula for these measures. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discrepancy of randomly sampled sequences of reals
Authors: Weber Michel
Published: June 2004

We estimate the discrepancy of (nx) when n is sampled by a random walk and give examples involving the diophantine approximation properties of x. The proof relies upon the combination of the metric entropy method and the Erdös‐Turan inequality. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron‐Beam Irradiation in TEM of Hard‐Segment Homopolymers and Polyurethanes with Different Hard‐Segment Content
Authors: Janik Helena
Published: June 2004

Summary: A hard‐segment homopolymer (HSH) and segmented poly(ester urethanes) (PESU) were studied by TEM to estimate their stability against electron‐beam irradiation. The bright‐field image and electron‐diffraction modes in TEM and optical polarised microscopy were used. It is shown that both soft and hard segments are sensitive to the electron beam. None of the films was stable enough to register an electron‐diffraction pattern without damage.

Electron‐diffraction pattern taken from the film of hard‐segment homopolymer crystallised at 100 °C from DMF: (a) the pattern registered immediately; (b) the pattern registered after 5 s of exposure in the TEM at the same place.

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Electron‐diffraction pattern taken from the film of hard‐segment homopolymer crystallised at 100 °C from DMF: (a) the pattern registered immediately; (b) the pattern registered after 5 s of exposure in the TEM at the same place.
Photo‐Rheometry/NIR Spectrometry: An in situ Technique for Monitoring Conversion and Viscoelastic Properties during Photopolymerization
Authors: Botella Aurélie , Dupuy Jérôme , Roche Alain‐André , Sautereau Henry , Verney Vincent
Published: June 2004

Summary: A suitable rheometer for simultaneous dynamic mechanical analysis (DMA) and NIR (Near Infra‐Red) in situ analysis during UV curing was developed. The conversion and viscoelastic properties of a dimethacrylate/styrene‐based system were investigated. The results were plotted against both irradiation time and total average conversion. For the same conversion, a lower intensity delays the reaction but does not affect the viscoelastic properties.

A device for simultaneous photo‐rheology and NIR spectroscopy experiments.

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A device for simultaneous photo‐rheology and NIR spectroscopy experiments.
Complex Formation between Polyisoprene and Cyclodextrins
Authors: Michishita Takeshi , Takashima Yoshinori , Harada Akira
Published: June 2004

Summary: Polyisoprenes were found to form inclusion complexes with cyclodextrins with high selectivity to give crystalline compounds. β‐Cyclodextrin formed complexes only with polyisoprene of low molecular weight, whereas γ‐cyclodextrin formed complexes with polyisoprenes of high molecular weight. α‐Cyclodextrin did not form complexes with polyisoprene of any molecular weight. The yields of γ‐cyclodextrin complexes increased with increasing molecular weights of the polyisoprenes and reached a maximum of around several thousands, and then decreased.

Theoretical depiction of the complex formed between polyisoprene and γ‐CD, as determined by molecular modelling studies. The PIP chain is shown penetrating the γ‐CD cavity, which, in turn, accommodates one to 1.5 monomer units of PIP.

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Theoretical depiction of the complex formed between polyisoprene and γ‐CD, as determined by molecular modelling studies. The PIP chain is shown penetrating the γ‐CD cavity, which, in turn, accommodates one to 1.5 monomer units of PIP.
Synthesis and Characterization of Star‐Shaped Diblock Poly(ε‐caprolactone)/Poly(ethylene oxide) Copolymers
Authors: Maglio Giovanni , Nese Giuseppe , Nuzzo Margherita , Palumbo Rosario
Published: June 2004

Summary: Star‐shaped hydroxy‐terminated poly(ε‐caprolactone)s (ssPCL), with arms of different lengths, were obtained by ring‐opening polymerization (ROP) of ε‐caprolactone initiated by pentaerythritol, and were condensed with α‐methyl‐ω‐(3‐carboxypropionyloxy)‐poly(ethylene oxide)s ($\overline M _{\rm n}$ = 550–5 000) to afford four‐armed PCL‐PEO star diblock copolymers (ssPCL‐PEO). The polymers were characterized by 1H and 13C NMR spectroscopy and size‐exclusion chromatography (SEC). The melting behavior of ssPCLs was studied by differential scanning calorimetry (DSC). X‐ray diffraction and DSC techniques were used to investigate the crystalline phases of ssPCL‐PEOs.

The part of the synthesis of four‐armed star‐shaped diblock poly(ε‐caprolactone)‐poly(ethylene oxide) copolymers as described.

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The part of the synthesis of four‐armed star‐shaped diblock poly(ε‐caprolactone)‐poly(ethylene oxide) copolymers as described.
CASK and Dlg form a PDZ protein complex at the mammalian neuromuscular junction
Authors: Sanford Jamie L. , Mays Tessily A. , Rafael‐Fortney Jill A.
Published: June 2004

Membrane‐associated guanylate kinases (MAGUKs) are modular adapter proteins that serve as scaffolding molecules and anchor channels and receptors via their PDZ (PSD‐95, Dlg, Zo‐1) domains. Calcium, calmodulin‐associated serine/threonine kinase (CASK) is a MAGUK that is critical at synapses in the central nervous system and at cell–cell junctions because of its interactions with channels, receptors, and structural proteins. We show via confocal microscopy that CASK and another MAGUK, Discs Large (Dlg), are present at the mammalian neuromuscular junction in skeletal muscle. Immunoprecipitation data from mouse muscle show that CASK associates with Dlg, providing evidence of a MAGUK protein complex at this synapse. These data indicate that CASK and Dlg may act as a scaffold for organizing receptors and channels at the postsynaptic membrane of the neuromuscular junction. Muscle Nerve 30: 164–171, 2004
Target‐derived and locally derived neurotrophins support retinal ganglion cell survival in the neonatal rat retina
Authors: Spalding Kirsty L. , Rush Robert A. , Harvey Alan R.
Published: June 2004

Brain‐derived neurotrophic factor (BDNF) and neurotrophin‐4/5 (NT‐4/5) protein and mRNA are found in the neonatal rat retina and also in target sites such as the superficial layers of the superior colliculus. Both neurotrophins support neonatal retinal ganglion cell survival in vitro. In vivo, injections of recombinant BDNF and NT‐4/5 reduce naturally occurring cell death as well as death induced by removal of the contralateral superior colliculus. In the latter case, the peak of retinal ganglion cell death occurs about 24 h postlesion. We wished to determine: whether a similar time‐course of degeneration occurs after selective removal of target cells or depletion of target‐derived trophic factors, and whether ganglion cell viability also depends on intraretinally derived neurotrophins. Retinal ganglion cell death was measured 24 and 48 h following injections of kainic acid or a mixture of BDNF and NT‐4/5 blocking antibodies into the superior colliculus and 24 h after intraocular injection of the same antibodies. Retinotectally projecting ganglion cells were identified by retrograde labeling with the nucleophilic dye diamidino yellow. We show that collicular injections of either kainic acid or BDNF and NT‐4/5 blocking antibodies significantly increased retinal ganglion cell death in the neonatal rat 24 h postinjection, death rates returning to normal by 48 h. This increase in death was greatest following collicular injections; however, death was also significantly increased 24 h following intravitreal antibody injection. Thus retinal ganglion cell survival during postnatal development is not only dependent upon trophic factors produced by central targets but may also be influenced by local intraretinal neurotrophin release. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 319–327, 2004
Crystallization and melting behaviour of polypropylene/barium sulfate composites
Authors: Wang Ke , Wu Jingshen , Zeng Han‐Min
Published: June 2004

The effects of polypropylene (PP)–barium sulfate (BaSO4) interfacial interaction on the crystallization and melting behaviour of PP/BaSO4 composites were investigated by means of differential scanning calorimetry. The results show that BaSO4 can act as nucleating agent and the nucleation activity increases when the PP–BaSO4 interface is modified. Neat PP exhibits a single fusion endotherm after being non‐isothermally crystallized, whereas the PP/BaSO4 composites show dual endotherms or a broad endotherm with a shoulder at the low temperature side, indicating that there are more crystallites with less perfection formed in the composite samples. It is shown that the hindrance of BaSO4 particles on the transport of PP chains to the crystallization zone is responsible for the formation of the less perfect crystallites. Moreover, the melting patterns of the composites are different from sample to sample, which can be attributed to the different extents of deviation from equilibrium at which the crystallization processes proceeded. Copyright © 2004 Society of Chemical Industry
Cationic electron‐beam curing of a high‐functionality epoxy: effect of post‐curing on glass transition and conversion
Authors: Rath SK , Boey FYC , Abadie MJM
Published: June 2004

This paper reports on the cationic electron‐beam curing of a high‐functionality SU8 epoxy resin, which is extensively used as a UV‐curing negative photoresist for micro‐electronics machine systems (MEMS) applications. Results show that elevated post‐curing treatment significantly increased both the conversion and the glass transition. The degree of conversion and the glass transition temperature were measured by using Fourier‐transform infrared (FTIR) spectroscopy and modulated differential scanning calorimetry (MDSC®), respectively. The glass transition temperature (Tg), which has been observed to be dependent on the degree of conversion, reaches a maximum of 162 °C at 50 Mrad and post‐curing at 90 °C. The degradation pattern of the cured resin does not show much variation for exposure at 5 Mrad, but does show significant variation for 50 Mrad exposure at various post‐curing temperatures. A degree of conversion of more than 0.8 was achieved at a dosage of 30 Mrad with post curing at 80 °C, for the epoxy resin with an average functionality of 8 a feature simply not achievable when using UV‐curing. Copyright © 2004 Society of Chemical Industry
Space‐charge limited conduction in polyaniline films
Authors: Nazeer K Prem , Jacob Sheeba Anu , Thamilselvan M , Mangalaraj D , Narayandass Sa K , Yi Junsin
Published: June 2004

Polyaniline emeraldine base (PANI‐EB) powder was synthesized by oxidative polymerization of aniline. The PANI‐EB films were prepared by the solution‐casting technique. The temperature‐dependent dc conductivity measured in the range 173–303 K suggests that the PANI‐EB is a quasi‐one‐dimensional disordered conductor. The current‐voltage characteristics of the PANI‐EB films measured in the range 333–383 K showed the SCLC mechanism. The SCLC parameters such as free carrier density (p0), trap density (pt), the ratio between free carrier density to the total carrier density (θ), mobility (µ) and the effective hole mobility (µeff) were calculated. The activation energy (Ea = 0.32 eV) and the Fermi level (EF = 0.42 eV) were estimated. As well as these, the trap parameters such as the trap filled limit voltage (VTFL), the shallow trap density (Nt), the depth of the dominant trap level (Et − Ev), the density of states within the hole mobility edge (Nv) and the characteristic energy (Ec) were also calculated and presented. The exponential type of traps distribution with large number of traps was found to be due to the disorder and moisture in the polymer films. Copyright © 2004 Society of Chemical Industry
Comparative study of PHBV/TBP and PHBV/BPA blends
Authors: Fei Bin , Chen Cheng , Wu Hang , Peng Shuwen , Wang Xiuyan , Dong Lisong
Published: June 2004

In order to clarify the effects of phenols on properties of polyesters, the blends of poly[(3‐hydroxybutyrate)‐co‐(3‐hydroxyvalerate)] (PHBV) with 4,4′‐dihydroxydiphenylpropane (BPA) and p‐tert‐butylphenol (TBP) were studied. The FTIR spectra revealed that there was strong hydrogen‐bond (H‐bond) interaction between PHBV and both phenols. By evaluating the fraction of H‐bonded CO in the blend, it was concluded that BPA showed a stronger tendency than TBP to form H‐bonds with PHBV. Accordingly, BPA formed a stronger suppression than TBP on the crystallization of PHBV. When 30 wt% BPA or 50 wt% TBP were added into PHBV, the crystallization of PHBV was completely suppressed in the DSC cooling scan. As the phenol content was increased, the Tg of PHBV/TBP blend decreased while the Tg of PHBV/BPA blend increased. This difference indicated that TBP and BPA acted as plasticizer and physical crosslinking agent, respectively. Copyright © 2004 Society of Chemical Industry
Heterogeneous blends of recycled poly(ethylene terephthalate) with impact modifiers: phase structure and tensile creep
Authors: Pegoretti Alessandro , Kolarík Jan , Gottardi Gianluca , Penati Amabile
Published: June 2004

Several types of photomicrographs have concurrently shown that impact modifiers (IMs) form particles (on a micrometre scale) which are evenly dispersed in a recycled poly(ethylene terephthalate) (PET) matrix; their adhesion to the latter is high enough that fracture surfaces (produced in liquid nitrogen) do not follow the interface. An essential part of the tensile creep of PET corresponds to the elastic time‐independent component; the time‐dependent component is rather limited, even if relatively high stresses are applied. Thus, the tensile compliance of PET is virtually independent of the applied stress, which indicates linear viscoelastic behaviour. The compliance of PET/IM blends (93/7, 90/10, 85/15 (by weight)) grows with the IM content and its time‐dependence becomes more visible. The effects of the two types of IM used in this study seem to be practically identical from the viewpoint of dimensional stability of the blends. The logarithm of compliance grows with the logarithm of time faster than linearly, and this tendency becomes more apparent with increasing fraction of IM. Even if the strain‐induced free volume is taken into account, a noticeable upswing of the compliance for longer creep periods (t > 1000 min) is evident. This cannot be interpreted as a consequence of the flow, because the recovery following the creep has proved the complete reversibility of the previous deformation. A simple empirical equation is proposed, which provides a plausible prediction of the creep behaviour of PET with dispersed impact modifiers. Copyright © 2004 Society of Chemical Industry
Rapid living free‐radical polymerization of methyl acrylate under 60Co γ‐ray irradiation at room temperature
Authors: Hua Daoben , Cheng Kun , Bai Ruke , Lu Weiqi , Pan Caiyuan
Published: June 2004

Rapid living free‐radical polymerization of methyl acrylate under 60Co γ‐ray irradiation in the presence of benzyl 1H‐imidazole‐1‐carbodithioate at room temperature is reported. The results showed that the polymerization is a fast living process, and that the molecular weight of the polymer is as high as 39 600 g mol−1 at 68 % conversion with Mw/Mn = 1.09 within 68 min. The polymerization rate was markedly influenced by the structures of thiocarbonylthio compounds. Copyright © 2004 Society of Chemical Industry
New antigenic candidates in multiple sclerosis: Identification by serological proteome analysis
Authors: Almeras Lionel , Lefranc Didier , Drobecq Hervé , de Seze Jérome , Dubucquoi Sylvain , Vermersch Patrick , Prin Lionel
Published: June 2004

Myelin antigen targets that are clearly associated with pathogenic events in multiple sclerosis (M.S.) patients remain to be defined. We recently demonstrated that the analysis of global IgG antibody response against human brain antigens using one‐dimensional (1‐D) immunoblotting, allowed us to discriminate M.S. patients from controls (both healthy subjects and patients with Sjögren's syndrome). Additionally, this approach also differentiated the three clinical forms of M.S. Indeed, 42 brain antigenic bands (26 from healthy brain and 16 from the M.S. brain) showed the discriminant IgG immune responses. The aim of our study was to characterize the 26 discriminant antigenic bands detected in healthy brain. Protein identification was successively performed by 1‐D and two‐dimensional (2‐D) immunoblottings using sera from 18 M.S. patients, followed by mass spectrometry (MS) analysis and a database search. One hundred and two antigenic spots were then detected on 2‐D immunoblots, with M.S. sera against healthy brains. Sixty‐four spots were successfully matched with 2‐D Coomassie brillant blue stained gels, which were further selected for MS analysis and annotated leading to the identification of 14 of the 26 discriminant antigens. Thus, serological proteome analysis may provide a useful tool for the identification of potentially new M.S.‐associated antigens, whose relevance to physiopathological events remains to be defined.
Synthesis of azobenzene‐containing polythiophenes and photoinduced anisotropy
Authors: Aubertin Francois , Zhao Yue
Published: June 2004

Three new polythiophenes containing an azobenzene moiety in the side‐chain were synthesized and characterized. Two of them, which are slightly soluble in tetrahydrofuran to allow the preparation of thin films from solution casting, were used to investigate the photoinduced anisotropy arising from the photoisomerization of azobenzene in this type of polymer. The results show that, unlike other amorphous azobenzene polymers, only an extremely small anisotropy can be induced on excitation with an Ar+ laser at 488 nm in these azobenzene‐containing polythiophenes, and that this photoinduced anisotropy is observable only by heating the polymer to some temperatures below glass transition temperature. It is suggested that the inability for azobenzene polythiophenes to display a significant photoinduced anisotropy may be caused by some structural constraints and/or a severe interference from conjugated thiophene chains that absorb strongly in the visible region. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3445–3455, 2004
Synthesis, characterization, and emulsion polymerization of polymerizable coumarin derivatives
Authors: Oh Jung Kwon , Stöeva Valentina , Rademacher Jude , Farwaha Rajeev , Winnik Mitchell A.
Published: June 2004

We describe the synthesis of a new polymerizable coumarin derivative, [6‐(β‐acryloxyethoxy)‐7‐isopropoxy‐4‐methyl coumarin (3)], whose UV absorption spectrum significantly overlaps the emission spectrum of 9‐alkyl phenanthrene chromophore. This dye can serve several purposes in latex films. It can be a tracer for fluorescence microscopy experiments, or it can act as a donor or acceptor dye in nonradiative energy transfer experiments. Here we emphasize its role as an energy transfer acceptor in experiments with phenanthrene as the corresponding donor. Coumarin‐labeled poly(butyl methacrylate) latex dispersions could be synthesized by conventional batch emulsion polymerization with complete monomer conversion, complete dye incorporation, and uniform dye distribution. Attempts to extend this reaction to poly(vinyl acetate) copolymers failed because the dye inhibited monomer conversion. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3479–3489, 2004
Preparation and thermomechanical properties of epoxy resins modified by octafunctional cubic silsesquioxane epoxides
Authors: Mya Khine Yi , He Chaobin , Huang Junchao , Xiao Yang , Dai Jie , Siow Yeen‐Ping
Published: June 2004

The thermomechanical properties of octafunctional cubic silsesquioxane‐modified epoxy resins associated with dicycloaliphatic hardener (4,4′‐dimethyldiaminodicyclo hexyl methane) were studied using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The structures of epoxy resin containing cubic silsesquioxane epoxides were characterized by Fourier transform infrared spectroscopy and wide‐angle X‐ray scattering techniques. In this work, octa(dimethylsiloxybutylepoxide) octasilsesquioxane (OB), and octa(glycidyldimethyl‐siloxyepoxide) octasilsesquioxane (OG), were synthesized and used as additives to improve the properties of a commercial epoxy resin by exploring the effects of varying the ratio of OB or OG. The commercial Ciba epoxy resin (Araldite LY5210/HY2954) was used as a standard. It was found, by thermogravimetric analysis and dynamic mechanical analysis, that the highest thermal stability was observed atN= 0.5 (N= number of amine groups/number of epoxy rings). No glass transition temperature was observed by adding 20 mol % OB to the Ciba epoxy resin, indicating the reduction of chain motion in the presence of octafunctional cubic silsesquioxane epoxide. The storage modulus of the OB‐modified epoxy resin also increased, especially at higher temperatures, compared with the Ciba epoxy resin under identical curing conditions. Fourier transform infrared data elucidated the preservation of cubic silsesquioxane structure after curing at high temperature. In contrast, the OG/Araldite LY5210/HY2954 systems gave poorer thermomechanical properties. The low viscosity of OB at room temperature (∼ 350 cPs) makes it suitable for composite processing and, when used in conjunction with the Ciba epoxy, lowers the viscosity of this system as well. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3490–3503, 2004
Physicochemical characterization of α‐chitin, β‐chitin, and γ‐chitin separated from natural resources
Authors: Jang Mi‐Kyeong , Kong Byeong‐Gi , Jeong Young‐Il , Lee Chang Hyung , Nah Jae‐Woon
Published: June 2004

We isolated α‐chitin, β‐chitin, and γ‐chitin from natural resources by a chemical method to investigate the crystalline structure of chitin. Its characteristics were identified with Fourier transform infrared (FTIR) and solid‐state cross‐polarization/magic‐angle‐spinning (CP–MAS) 13C NMR spectrophotometers. The average molecular weights of α‐chitin, β‐chitin, and γ‐chitin, calculated with the relative viscosity, were about 701, 612, and 524 kDa, respectively. In the FTIR spectra, α‐chitin, β‐chitin, and γ‐chitin showed a doublet, a singlet, and a semidoublet at the amide I band, respectively. The solid‐state CP–MAS 13C NMR spectra revealed that α‐chitin was sharply resolved around 73 and 75 ppm and that β‐chitin had a singlet around 74 ppm. For γ‐chitin, two signals appeared around 73 and 75 ppm. From the X‐ray diffraction results, α‐chitin was observed to have four crystalline reflections at 9.6, 19.6, 21.1, and 23.7 by the crystalline structure. Also, β‐chitin was observed to have two crystalline reflections at 9.1 and 20.3 by the crystalline structure. γ‐Chitin, having an antiparallel and parallel structure, was similar in its X‐ray diffraction patterns to α‐chitin. The exothermic peaks of α‐chitin, β‐chitin, and γ‐chitin appeared at 330, 230, and 310, respectively. The thermal decomposition activation energies of α‐chitin, β‐chitin, and γ‐chitin, calculated by thermogravimetric analysis, were 60.56, 58.16, and 59.26 kJ mol−1, respectively. With the Arrhenius law, ln β was plotted against the reciprocal of the maximum decomposition temperature as a straight line; there was a large slope for large activation energies and a small slope for small activation energies. α‐Chitin with high activation energies was very temperature‐sensitive; β‐Chitin with low activation energies was relatively temperature‐insensitive. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3423–3432, 2004
Synthesis and nuclear magnetic resonance analysis of starch‐g‐poly(1,4‐dioxan‐2‐one) copolymers
Authors: Wang Xiu‐Li , Yang Ke‐Ke , Wang Yu‐Zhong , Zhou Zhi‐Xuan , Jin Yong‐Dong
Published: June 2004

A new biodegradable starch graft copolymer, starch‐g‐poly(1,4‐dioxan‐2‐one), was synthesized through the ring‐opening graft polymerization of 1,4‐dioxan‐2‐one onto a starch backbone. The grafting reactions were conducted with various 1,4‐dioxan‐2‐one/starch feed ratios to obtain starch‐g‐poly(1,4‐dioxan‐2‐one) copolymers with various poly(1,4‐dioxan‐2‐one) graft structures. The microstructure of starch‐g‐poly(1,4‐dioxan‐2‐one) was characterized in detail with one‐ and two‐dimensional NMR spectroscopy. The effect of the feed composition on the resulting microstructure of starch‐g‐poly(1,4‐dioxan‐2‐one) was investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3417–3422, 2004
Borderline cases in density functional theory
Authors: Fritsche L. , Koller J. , Reinert Th.
Published: June 2004

We discuss two examples (antiferromagnetic order in transition metal oxides and van der Waals interaction) where density functional theory (DFT) seems to fail in giving an appropriate description of the actual physical situation. We analyze whether or not this failure reflects only a shortcoming of the approximations to the exchange‐correlation functionals that are commonly used. It is shown that the well‐known incapability of DFT to yield the correct antiferromagnetic (AF) moment and insulating properties of CoO and stoichiometric La2CuO4 may be indicative of a more fundamental deficiency, namely, absence of an exact noninteracting V‐representability of the spin densities in AF materials. By enlarging and reducing the self‐consistent DFT spin densities by an appropriate amount and simultaneously keeping the total densities fixed, one can turn CoO and La2CuO4 into insulators with the correct AF moments. We also discuss the ground‐state energy of two noble gas atoms of radius R0 at a distance R ≫ 2R0, for which situation an exact DFT should yield a 1/R6‐dependence for the difference between the total energy of the bi‐atom and the two atoms at infinite separation. Even if one improves the local density approximation to the exchange‐correlation energy by gradient corrections, this dependence remains outside the current practical framework of DFT. We report and practically check a simple idea as to how this difficulty can be overcome. The method we develop also might prove useful in actually calculating the above defect spin densities for critical AF materials. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004