bluuebunny/crossref_metadata_2025 huggingface dataset:
Sumanirole versus placebo or ropinirole for the adjunctive treatment of patients with advanced Parkinson's disease
Authors: Barone Paolo , Lamb Janice , Ellis Amanda , Clarke Zoe ,   Sumanirole for Advanced Parkinson's Disease Study Group
Published: November 2006

The aims of this study were to assess the safety, tolerability, and efficacy of sumanirole, a highly selective D2 dopamine receptor agonist, versus placebo in subjects with advanced Parkinson's disease (PD), and to demonstrate noninferiority of sumanirole to ropinirole. In this flexible‐dose, randomized, double‐blind, double‐dummy, parallel‐group study, 948 subjects were treated with sumanirole 1 to 48 mg/day, ropinirole 0.75 to 24 mg/day, or placebo. Treatment consisted of 13 weeks of dose escalation, 26 weeks of maintenance, and 1 week of tapering. Approximately 70% of subjects treated with either sumanirole or ropinirole completed the study. Statistical significance (P < 0.0001) was achieved when both sumanirole and ropinirole groups were compared with placebo, with mean differences of −7.7 and −8.8 on combined sum of the Unified Parkinson's Disease Rating Scale (UPDRS) part II (average on and off) and part III total scores at the end of maintenance. Noninferiority of sumanirole to ropinirole was also demonstrated, with a sumanirole minus ropinirole difference of 1.17 (90% CI: −0.56 to 2.89). Both dopamine agonists, sumanirole and ropinirole, were statistically superior compared with placebo as adjunctive therapy for patients with advanced Parkinson's disease, based on UPDRS II + III total score. Noninferiority of sumanirole to ropinirole was established, with comparable tolerability profiles. © 2006 Movement Disorder Society
Convergence rates toward the travelling waves for a model system of the radiating gas
Authors: Nishikawa Masataka , Nishibata Shinya
Published: November 2006

The present paper is concerned with an asymptotics of a solution to the model system of radiating gas. The previous researches have shown that the solution converges to a travelling wave with a rate (1 + t)−1/4 as time t tends to infinity provided that an initial data is given by a small perturbation from the travelling wave in the suitable Sobolev space and the perturbation is integrable. In this paper, we make more elaborate analysis under suitable assumptions on initial data in order to obtain shaper convergence rates than previous researches. The first result is that if the initial data decays at the spatial asymptotic point with a certain algebraic rate, then this rate reflects the time asymptotic convergence rate. Precisely, this convergence rate is completely same as the spatial convergence rate of the initial perturbation. The second result is that if the initial data is given by the Riemann data, an admissible weak solution, which has a discontinuity, converges to the travelling wave exponentially fast. Both of two results are proved by obtaining decay estimates in time through energy methods with suitably chosen weight functions. Copyright © 2006 John Wiley & Sons, Ltd.
The Laplace and the linear elasticity problems near polyhedral corners and associated eigenvalue problems
Authors: Meyer Arnd , Pester Cornelia
Published: November 2006

For domains with concave corners, the solutions to elliptic boundary values have the typical rα‐singularity. The so‐called singularity exponents α are the eigenvalues of an eigenvalue problem which is associated with the given boundary value problem. This paper is aimed at deriving the mentioned eigenvalue problems for two examples, the Laplace equation and the linear elasticity problem.

We will show interesting properties of these eigenvalue problems. For the linear elasticity problem, we explain in addition why the classical symmetry and positivity assumptions of the material tensor have to be used with care. Copyright © 2006 John Wiley & Sons, Ltd.
The total ponderomotive force and inhomogeneity indicators
Authors: Langemann Dirk
Published: November 2006

Droplets on outdoor high‐voltage equipment suffer a total ponderomotive force which is non‐vanishing in general. We show that this force can be given as a series of inhomogeneity indicators of the undisturbed electric field in the absence of the droplet. We use 2d and 3d Fourier techniques to prove the series expansion as a relation between the solutions of two Poisson's equations on different domains. The order of magnitude of the terms in the series expansion is discussed. It is found that the expansion converges fast in applicatory cases. The results are applied for droplets on a realistically shaped insulator. Copyright © 2006 John Wiley & Sons, Ltd.
Structural characterisation of poly(amidoamine) networks via high‐resolution magic angle spinning NMR
Authors: Annunziata R. , Franchini J. , Ranucci E. , Ferruti P.
Published: November 2006

A comprehensive structural characterisation of cross‐linked insoluble poly(amidoamine) (PAA) networks was performed by high‐resolution magic angle spinning (HRMAS) NMR spectroscopy. Model samples with 20%, 40% and 80% cross‐linking degrees were prepared and the best conditions to obtain high‐resolution spectra in the gel phase determined. Whereas the samples with 20% and 40% cross‐linking degrees could be exhaustively resolved and described, the sample with 80% cross‐linking degree could not be characterised by this technique owing to insufficient mobility of the polymer segments. Even with this limitation, the method developed in this study can be reasonably considered as a general one, which enables exhaustive characterisation of cross‐linked PAA networks of biomedical interest. Copyright © 2006 John Wiley & Sons, Ltd.
Spectral assignments for 1H,13C and 15N solution and solid‐state NMR spectra of s‐tetrazine and dihydro‐s‐tetrazine derivatives
Authors: Palmas Pascal , Girard Elzéar , Pasquinet Eric , Caron Thomas , Poullain Didier
Published: November 2006

Tetrazine‐based organic species are interesting intermediates for organic synthesis and represent a source of new materials bearing specific properties with potential applications in biology and material science. 1H, 13C, 15N NMR measurements carried out in solution and in the solid‐state have been used to characterize a series of 3,6‐disubstituted 1,2,4,5‐tetrazine/dihydrotetrazine new derivatives. Experimental results presented here provide data for the assignment of 15N chemical shifts including new organic small molecules; two polymers having the tetrazine ring in the main chain and several previously published compounds. We report apparently for the first time 15N experimental chemical shift data for tetrazine systems in the solid state. Copyright © 2007 John Wiley & Sons, Ltd.
Structural determination of three new germacrane‐type sesquiterpene alcohols from curdione by microbial transformation
Authors: Ma Xiao‐chi , Zheng Jian , Wu Li‐jun , Guo De‐an
Published: November 2006

Five germacrane‐type sesquiterpene alcohols obtained from curdione (1) by microbial biotransformation were isolated. Their structures were characterized as (2R)‐2β‐hydroxycurdione (2), 1α, 10β‐epoxy‐11‐hydroxycurdione (3), (2S)‐2α, 11‐dihydroxycurdione (4), 11,15‐dihydroxycurdione (5) and (3R)‐3α‐hydroxycurdione (6) based on the extensive NMR studies. Among them, 4, 5 and 6 are new compounds. Copyright © 2007 John Wiley & Sons, Ltd.
Reaction of o‐phenylenediamine with diacetyl monoxime: characterisation of the product by solid‐state 13C and 15N MAS NMR
Authors: Radhakrishnan T. , Sreekumari Nair P. , Kolawole G. A. , Revaprasadu N. , Hawkes G. E. , Motevalli M. , Bento E. S. , O'Brien P.
Published: November 2006

2,3‐Dimethylquinoxaline (DMQ) and dimethylglyoxime (DMGH2) form a 1:1 hydrogen‐bonded complex in the solid state, which is completely dissociated in methanol solution. There are small differences in solid‐state 13C shifts between the separated components DMQ and DMGH2 and the complex. The changes in 15N solid‐state chemical shifts are more significant: the hydrogen bond imparting a low frequency shift of ca 19 ppm. The effect of direct protonation on the DMQ solid‐state 15N shifts was measured, and the experimental 15N data correlated with those from GIAO molecular orbital (MO) calculations. Copyright © 2007 John Wiley & Sons, Ltd.
Improvements in the model for interoperability of intrusion detection responses compatible with the IDWG model
Authors: da Silva Paulo Fernando , Westphall Carlos Becker
Published: November 2006

This paper presents a model for response interoperability between intruder detection systems (IDSs), compatible with the model for alert interoperability developed by the Intrusion Detection Working Group (IDWG). Alterations in IDS IDWG architecture are proposed in order to provide for response interoperability support. The development and testing of the proposed model and its components are also presented. Copyright © 2006 John Wiley & Sons, Ltd.
Broadband Internet network management software platform and systems in KT
Authors: Yoo Jae‐Hyoung
Published: November 2006

The high penetration rate of Internet access services in Korea has created an operational environment that is different from those of other countries, and thus the level of customer needs takes on different aspects. To meet the operational environment, customer needs and rapid time to market requirements, Korea Telecom (KT) developed a scalable and flexible Internet network management system software (NMS S/W) platform, on which many NMSs have been implemented. This paper introduces KT's Internet network architecture, broadband services and operational environment. It also presents the software architecture of the NMS platform and application functions of major NMSs that are implemented on the platform. Furthermore, the future perspective of KT's network management technologies is described. Copyright © 2006 John Wiley & Sons, Ltd.
Customer‐centric service quality management for SK Telecom's mobile packet service
Authors: Kim Jisun , Park Jong Hoon , Kim Sung , Lee Dong Geol , Kim Yo Sub , Jin Sang Hyun
Published: November 2006

The research objective of our work is to improve the current quality management system by understanding the service quality that customers perceive. Also, the study aims to enhance work efficiency through the end‐to‐end quality of service (QoS) analysis from the user's terminal to the service server, eliminating the overlaps of QoS degradation analyses involving the wireless network, core network, and platform network. Against this backdrop, this paper intends to identify the elements of quality degradation in mobile packet service perceived at subscriber level and to propose a method that implements customer‐centric service quality management. To this end, we have assessed the packet services available from SK Telecom and came up with a methodology that derives service availability as a uniform indicator for subscriber‐perceived service quality according to the characteristics of different kinds of packet services. Also, using an embodied system, we performed an analysis on the correlation between service availability, which is a subscriber‐perceived quality indicator as monitored by commercial networks, and the actual measurement data. It was confirmed that we could have an end‐to‐end service quality management system that is more service‐oriented and customer‐centric than the current system‐oriented quality monitoring practices. Copyright © 2006 John Wiley & Sons, Ltd.
Wireless broadband services and network management system in KT
Authors: Lee Dong‐Hyun , Lee Hwan‐Joong , Lee Young‐Woo , Shin Dong‐Houn
Published: November 2006

As mobile devices such as laptops and PDAs are becoming widely available, customers' needs for portable Internet services are increasing. KT has been preparing to launch a WiBro (Mobile WiMax) service that is a high‐speed, low‐cost, wireless Internet service based on the IEEE 802.16e standard. WiBro Network Management System (WiBro‐NMS) has also been developed for the integrated management of WiBro network elements such as ACR, L2 switch, RAS and repeater. Because there is no standard management interface for the WiBro service, the design of a management interface is necessary to manage the multi‐vendor, heterogeneous network efficiently. In this paper, we discuss our two management interface specifications: XML web service‐based NML‐EML interface specification and management information base for WiBro repeater. We also describe the details of WiBro‐NMS, which has been developed based on the management interfaces. Copyright © 2006 John Wiley & Sons, Ltd.
Power line communication network trial and management in Korea
Authors: Lee Jae‐Jo , Hong Choong Seon , Kang Joon‐Myung , Hong James Won‐Ki
Published: November 2006

Power line communication (PLC) has become an important network access technology to conveniently and effectively provide various useful services such as remote meter reading, broadband Internet access, and home networking services. As the deployment and use of PLC networks increase, it is essential that we need to be able to configure, monitor, and control the PLC network resources. In this paper, we present an overview of PLC network technology and describe a trial PLC network and its deployment in Korea. We then present the design and implementation of a network management system for PLC networks. The experience on the deployment and management of the trial PLC network is also presented. Copyright © 2006 John Wiley & Sons, Ltd.
Hydroelastic vibrations of flexible rectangular tanks partially filled with liquid
Authors: Zhou Ding , Liu Weiqing
Published: November 2006

In this paper, the three‐dimensional vibratory characteristics of flexible rectangular tanks partially filled with liquid are studied. The surface waves of the liquid are taken into account in the analysis. Both the bulging modes of the tank‐wall vibration and the sloshing modes of the liquid oscillation are investigated. The vibrating modes of the liquid–tank system are divided into four distinct categories: double symmetric modes (SS); antisymmetric–symmetric modes (AS); symmetric–antisymmetric modes (SA) and double antisymmetric modes (AA). Each of these categories is separately investigated. The velocity potential of the liquid is analytically deduced by using a combination of the superposition method and the method of separation of variables. According to the liquid–tank interface conditions and the orthogonality of trigonometric functions, the coefficients in the solution of liquid velocity potential are expressed in the integral forms including the tank–wall dynamic deflection. A set of reasonable static beam functions is constructed as the admissible functions of the tank‐wall vibration. The eigenfrequency equation of the liquid–tank system is derived by using a combination of the Rayleigh–Ritz method and the Galerkin method. Convergence study demonstrates the high accuracy and small computational cost of the proposed approach. Finally, some numerical results are presented for the first time. Copyright © 2006 John Wiley & Sons, Ltd.
Contrasting zonal LES and non‐linear zonal URANS models when predicting a complex electronics system flow
Authors: Liu Y. , Tucker P. G.
Published: November 2006

Zonal non‐linear URANS (unsteady Reynolds‐averaged Navier–Stokes) and hybrid RANS/LES (large eddy simulation) model variants are presented. Performances of these models are compared for an unsteady, relatively high Reynolds number, complex electronics‐related geometry, non‐isothermal flow. Comparison is made with heat transfer, velocity and turbulence intensity data. The URANS models investigated involve zonal k–l/EASM (explicit algebraic stress model) and k–l/HCubic (high Reynolds number cubic model) variants. A k–l‐based hybrid RANS/LES (zonal LES) method is also applied and four RANS–LES switching criteria considered. Results are found to be relatively insensitive to this. To aid comparisons, the Smagorinsky, Yoshizawa, non‐linear Kosovic and mixed Leray subgrid scale LES models are considered. All models give similar mean velocity predictions. However, for turbulence intensities, the hybrid RANS/LES and LES give considerably more accurate predictions than the URANS. For heat transfer, none of the models performs well. The local Nusselt number is largely overpredicted by the URANS and underpredicted by the hybrid RANS/LES. However, the worst hybrid RANS/LES model Nusselt number error is around 30% less than the best URANS model error. Also, the most accurate URANS heat transfer is for the crudest model. On average, the hybrid RANS/LES model heat transfer results are marginally more accurate than the LES. Copyright © 2006 John Wiley & Sons, Ltd.
Assessing the impact of stakeholder dialogue: changing relationships between NGOs and companies
Authors: Burchell Jon , Cook Joanne
Published: November 2006

In seeking to respond to criticisms regarding their social and environmental actions, companies have increasingly looked towards processes of stakeholder dialogue and engagement to increase trust and accountability, and provide better processes of communication regarding their activities. However, while stakeholder dialogue has become an increasingly central aspect of a companies CSR strategy, there is little detailed analysis, by which to assess the impact of these processes of dialogue in improving relationships between business and civil society. Similarly, little research has been conducted into the way in which dialogue impacts upon company strategy and policy, or upon how the dialogue process is perceived by the civil society organizations that the companies seek to bring into dialogue.

This article provides some insight into these areas by reflecting on the initial findings of an ongoing research project (CRADLE) into the impact of dialogue and exchange on the shaping of CSR. It presents the findings from a postal questionnaire distributed to companies NGOs and facilitator groups regarding the impact of CSR dialogue processes. In conjunction with subsequent interview findings, the article discusses both company and NGO attitudes towards stakeholder engagement processes, and the impact that this has had in changing organizational practices. In particular, it looks at the types of dialogue being undertaken, the links between dialogue and trust and the role of dialogue in shaping organizational learning. In general, the findings present an informative overview of the current perception of the value of dialogue processes from a cross‐section of groups directly involved within the CSR arena.

Copyright © 2006 John Wiley & Sons, Ltd.
Responsible business decisions: an over‐arching framework
Authors: Gully Alan , Stainer Lorice , Stainer Alan
Published: November 2006

Contemporary businesses face increasing pressures on formulating, implementing and monitoring their strategic policies. Their long‐term success in attaining these strongly relies on developing a proactive two‐way, or even multi‐way, stakeholder dialogue to become aware of the moral aspects of decisions. Openness and transparency should help to provide stakeholders with information on how and why particular courses of action have been adopted. In order to be effective and efficient, responsible business decision‐making requires the willpower and commitment by management to implement, monitor and evaluate the ethical action which ought to be based on the organisation's evolving values and priorities. Although inclusive relationships may be accomplished in several ways, the normative interpretation of stakeholder theory is the most appropriate methodology to enable moral judgement to be made. An over‐arching framework is presented to assess, review and re‐balance the different techniques for any business to achieve its intended outcomes through the triple bottom line.

Copyright © 2006 John Wiley & Sons, Ltd.
Safeguarding corporate social responsibility (CSR) in global supply chains: how codes of conduct are managed in buyer‐supplier relationships
Authors: Pedersen Esben Rahbek , Andersen Mette
Published: November 2006

In the wake of globalization, companies are becoming increasingly aware of the social and environmental aspects of international production. Companies of today not only have to be profitable, but they also have to be good corporate citizens. In response to the increasing societal pressure, many companies adopt the concept of corporate social responsibility (CSR) by introducing codes of conduct that are expected to ensure socially responsible business practises throughout the chain—from supplier of raw materials to final end‐users.

However, there are several challenges to the management and control of codes of conduct in global supply chains. Active commitment is a precondition for the successful implementation of the codes, but the incentive to comply with the codes does not necessarily extend to all the actors in the chain. Moreover, it is difficult to enforce codes of conduct in global supply chains, because the involved companies are separated geographically, economically, legally, culturally and politically. In consequence, introducing codes of conduct in global supply chains raises a series of agency problems that may result in non‐compliance.

Realizing that non‐compliance can have severe consequences for the initiator (due to consumer sanctions, negative press, capital loss, government interventions, damaged brand etc.), the article analyses how the interests of the actors in the supply chain can be aligned with the terms of the codes. IKEA is used as a ‘best case’ example to illustrate how codes of conduct can be effectively managed in the supply chain.

Copyright © 2006 John Wiley & Sons, Ltd.
Validation of a measure of societal marketing orientation
Authors: Ward Steven , Lewandowska Aleksandra
Published: November 2006

Although there has been much debate and interest in the practices of societal marketing, there is currently no accepted measure of this construct. A measurement of societal marketing validated by Structural Equation Modelling (SEM) suggested this measure was one dimensional and consisted of five items measuring the lobbying of government and the degree of business charity. The factor structure was robust and did not vary across the four counties in the study. The final measure was positively correlated with the Narver and Slater (1990) measure of marketing orientation, industry association and performance. There was thus considerable evidence found for the construct validity of the measurement of societal marketing.

Copyright © 2006 John Wiley & Sons, Ltd.
Polymers as functional components in batteries and fuel cells
Authors: Wegner Gerhard
Published: November 2006

The recent 10 years have seen an unprecedented development in the area of portable electronic devices: mobile phones, laptops, PDAS, and digital cameras have all become commodities on a large scale. All of these devices need a power supply in terms of a battery acceptable capacity, possibly rechargeable. This demand has triggered research and development in polymer materials science for lithium ion conducting polymers that could replace or avoid organic liquids as a supporting electrolyte. Moreover, polymers need to be optimized that act in the form of “gels” as framework and/or membrane materials to achieve mechanical integrity of the electrode compartments. Ionic conductivity for protons in polymeric systems is also the key issue in the development of so‐called polyelectrolyte‐membrane fuel cells (PEMFCs) that are supposed to work as power sources for mobile applications, e.g. in hybrid cars. A liquid fuel such as methanol would be converted to CO2 and H2O with concomitant production of electricity. Novel proton conducting polymer systems are required that work at temperatures between 150–200°C, that is under more or less water‐free conditions. These requirements find an echo in the academic world in terms of renewed interest in the mechanisms of ionic transport phenomena in polymeric systems and in studies that aim for optimization of materials. In this article there will be a report on both lithium‐ion and proton conducting polymers that have been recently developed in the authors' laboratory. The results will be discussed in the context of the demands that need to be met for advanced technologies. Copyright © 2006 John Wiley & Sons, Ltd.
Some comments on the main fire retardancy mechanisms in polymer nanocomposites
Authors: Schartel B. , Bartholmai M. , Knoll U.
Published: November 2006

Barrier formation and increasing the melt viscosity are addressed as the two main general fire retardancy mechanisms of polymer nanocomposites. They result in specific impacts on fire properties that consequentially cause varying flame retardancy efficiency in different fire tests. The barrier formation retards mainly flame spread (peak of heat release rate) in developing fires, but does not reduce fire load (total heat evolved), ignitability or flammability (limiting oxygen index, UL 94). Furthermore, this flame retardancy effect increases with increasing irradiation and vanishes with decreasing irradiation. The increased melt viscosity prevents dripping, which is beneficial or disadvantageous depending on the fire test used. In some test, it become the dominant influence, transforming self‐extinguishing samples into flammable materials or causing wicking. Advantages and the limits are sketched comprehensively for exploiting the main general fire retardancy mechanisms of polymer nanocomposites. It is concluded that barrier formation and changing the melt viscosity in nanocomposites are not sufficient for most applications, but must be accompanied by additional mechanisms in special systems or in combination with other flame retardants. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and polymerization reactions of cyclic imino ethers. 3. Poly(ester amide)s of the AA + BB type on the basis of 2‐oxazolines
Authors: Lustoň J. , Kronek J. , Markus O. , Janigová I. , Böhme F.
Published: November 2006

Polyaddition reaction of aromatic bis(2‐oxazolines) with aliphatic dicarboxylic acids, hence AA +  BB type reactions, was studied. 1,4‐Bis(2‐oxazolin‐2‐yl)benzene (TBOX) and 1,3‐bis(2‐oxazolin‐2‐yl) benzene (IBOX) as AA monomer and aliphatic dicarboxylic acids with the number of carbon atoms 4–12 as BB monomer were used. Polymerizations were thermally initiated in the range 90–250°C, in melt or in solution of high boiling aprotic solvents. The structure of the formed poly(amide esters) was proved by NMR spectroscopy. The effects of the structure of both comonomers, duration of polymerization, polymerization temperature, type of solvent, and concentration of monomers were studied. The molecular weights of the prepared polymers are in the range 2000–25,000 g/mol. Thermal properties of the prepared samples were studied, too. Copyright © 2006 John Wiley & Sons, Ltd.
Electrical properties of a rubber blend used in the tyre industry
Authors: Bošák Ondrej , Kalužný Ján , Preto Jozef , Vacval Jozef , Kubliha Marian , Hronkovič Ján
Published: November 2006

This paper shows the results of the measurement of the time dependences of direct and alternate electric conductivities in the temperature range 100–200°C measured during the vulcanization of a rubber blend. Using electrical methods, it is possible to investigate the quantity and the quality of the processes running during vulcanization. Copyright © 2006 John Wiley & Sons, Ltd.
Development and characterization of self‐reinforced poly(propylene) composites: carded mat reinforcement
Authors: Bárány T. , Karger‐Kocsis J. , Czigány T.
Published: November 2006

Self‐reinforced poly(propylene) (PP) composites were produced by film‐stacking using carded mats of α‐isotactic PP fibers and films of β‐isotactic PP. Composite sheets were produced at various consolidation temperatures (T = 150–170°C) and constant holding time (t = 2 min). In a test series the holding time was varied (t = 2–20 min) by keeping the consolidation temperature constant. The consolidation degree of the sheets was studied on polished sections by light microscopy and quantified by density and peel test results. Specimens cut of the sheets were subjected to in‐plane static tensile and out‐of‐plane dynamic impact (instrumented falling weight impact, IFWI) tests. It was established that the best indicators for the consolidation degree are the density, tensile strength and specific perforation impact energy and between them linear correlations exists. Increasing the density of the composites resulted in increased tensile strength (due to lower void content and better fiber/matrix adhesion) and reduced perforation impact energy (due to hindered delamination between the constituent layers). Copyright © 2006 John Wiley & Sons, Ltd.
Poly(oxyalkylene) grafts to guar gum with applications in hydraulic fracturing fluids
Authors: Bahamdan Ahmad , Daly William H.
Published: November 2006

Hydraulic fracturing is routinely used in the oil and gas industry to improve or stimulate the recovery of hydrocarbons from underground formations. Highly viscous fluids are used to carry proppants into the fractures; guar gum derivatives are commonly used because they can be degraded readily for subsequent removal. In this study a new series of carboxymethylated guar gum derivatives, which are modified via the corresponding methyl esters with poly(oxyalkylene amines) to produce a series of poly(oxyalkylene‐g‐guar) derivatives with unique rheological properties are reported. Techniques for gelling the derivatives and for breaking the gels will be discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Development of electric control catheter and tweezers for thrombosis sample in blood vessels using piezoelectric polymeric fibers
Authors: Tajitsu Yoshiro
Published: November 2006

Poly‐L‐lactic acid (PLLA) has recently attracted attention as a polymer which exhibits a high shear piezoelectric constant. In this study, it was possible to control the piezoelectric motion of the PLLA fiber by applying d.c. voltage and a.c. voltage similar to a piezoelectric actuator. Then, on the basis of the experimental results, an electric control catheter and tweezers, using PLLA fibers (PLLA fiber catheter/tweezers) was developed. In the demonstration, it was assumed that thrombosis in blood vessels occurred and it was attempted to remove the thrombosis from the affected area using the PLLA fiber catheter and tweezers. This very delicate operation was attempted under a microscope. Using the PLLA fiber catheter and tweezers, the affected area was excised. A video movie of the test demonstration was recorded using a CCD video camera. All stages proceeded well in this study. Copyright © 2006 John Wiley & Sons, Ltd.
Responsive micelles and vesicles based on polypeptide diblock copolymers
Authors: Chécot F. , Rodríguez‐Hernández J. , Gnanou Y. , Lecommandoux S.
Published: November 2006

The self‐assembly of well‐defined polypeptide‐based diblock copolymers into micelles and vesicles is presented. The stimuli‐responsive behavior of polypeptides to pH and ionic strength is used to produce stimuli‐responsive nanoparticles with a control size and shape. Results focusing on vesicles obtained from polypeptide‐based diblock copolymers that are particularly promising for biomedical application will be detailed by means of static and dynamic light scattering analysis, UV circular dichroism, NMR and small angle neutron scattering experiments. Also systems that are able to form vesicles with narrow size distributions at basic and acidic pH going through an intermediate state of single polymer chains are presented. These nanoparticles are particularly interesting for encapsulation and delivery purposes at a controlled pH. Finally, surface self‐assembly of micelles and vesicles will be shown as models for biological surfaces such as mucosal surfaces. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis of hydrogels by radiation‐induced cross‐linking of Pluronic® F127 in N2O‐saturated aqueous solution
Authors: Ulanski Piotr , Pawlowska Wioletta , Kadlubowski Slawomir , Henke Artur , Gottlieb Ronny , Arndt Karl‐Friedrich , Bromberg Lev , Hatton T. Alan , Rosiak Janusz M.
Published: November 2006

Pluronic F127, a tri‐block copolymer of poly(ethylene oxide) and poly(propylene oxide) of a nominal formula EO100‐PO65‐EO100, when subjected to the action of ionizing radiation in oxygen‐free, N2O‐saturated aqueous solution, undergoes predominantly cross‐linking by intermolecular recombination of polymer‐derived radicals. This manifests itself as an increase in average molecular weight and, at sufficiently high doses, as a formation of permanent hydrogel. Cross‐linking occurs with high yields. Side reactions include chain scission and traces of oxidation processes. Polymer concentration and temperature influence the yields of radiation‐induced reactions. This indicates that radiolysis mechanism depends on the spatial arrangement of Pluronic molecules, which can be organized into single chains, micelles, and physical gel. Macroscopic hydrogels of Pluronic are thermo‐sensitive (phase transition temperature behavior with the transition temperature, at the tested conditions, of ca. 27 °C). Pluronic gels are prone to oxidative degradation, both in an aqueous environment and in the dry state, especially at elevated temperatures. Copyright © 2006 John Wiley & Sons, Ltd.
PP/EPDM‐based thermoplastic dynamic vulcanizates with organoclay: morphology, mechanical and viscoelastic properties
Authors: Mirzazadeh H. , Katbab A. A.
Published: November 2006

Dynamically vulcanized nanocomposite thermoplastic vulcanizates (NC‐TPVs) based on ethylene‐propylene‐diene rubber (EPDM) and melt intercalated hybrid of poly(propylene) (PP)/maleic anhydride grafted poly(propylene) (PP‐g‐MA) with organo‐modified montmorillonite (org‐MMT) were prepared. X‐ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examination have been performed to evaluate the extent of the intercalation, as well as to characterize the microstructure developed during dynamic vulcanization. The organocaly was better intercalated and dispersed in the PP matrix of the NC‐TPV samples at low clay contents. The NC‐TPV samples showed a matrix‐disperse type of morphology in which the crosslinked EPDM particles appeared in the form of agglomerates covered by a layer of nanocomposite PP (NC‐PP). The NC‐TPV samples exhibited higher elastic modulus compared with similar but unfilled TPV sample in spite of the lower crystallization degree for the former. The storage modulus (G′) of the molten NC‐TPV proved to be highly frequency dependent. This was assigned to the formation of a nanoclay network structure by the NC‐PP covered EPDM rubber particles. Copyright © 2006 John Wiley & Sons, Ltd.
Semi‐continuous emulsion copolymerization of vinyl acetate and butyl acrylate using a new protective colloid. Part 1. Effect of different emulsifiers
Authors: Sarac Ayfer , Yildirim Hüseyin
Published: November 2006

Vinyl acetate and butyl acrylate copolymers were synthesized in the presence of ammonium persulfate initiator, emulsifiers having different character such as non‐ionic and anionic+non‐ionic emulsifiers, and N‐methylol acrylamide as a new protective colloid in a classical glass reactor. The monomer ratio was chosen 85:15. In the case of mixture emulsifiers, the series of non‐ionic emulsifiers which have 10 to 40 moles ethoxylated nonyl phenol except 20 moles were combined with sodium dodecyl benzene sulfonate. The effects of the new colloidal stabilization agent, and different emulsifiers on the physicochemical properties of the copolymers were investigated at a constant temperature of 70°C by measuring conversion, viscosity, molecular weights, and molecular weight distribution, respectively, by using gravimetric method, Brookfield viscometer, viscometric method, and gel permeation chromatograpy. It was determined that the original copolymer latexes viscosities increased with the increased chain length for the two types of emulsifiers, in general. Similar changes were also found in viscosity average, number average and weight average molecular weights of the copolymers for the different types of emulsifiers. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation of poly(vinyl pyrrolidone) grafted sulfonamide based polystyrene resin and its use for the removal of dye from water
Authors: Senkal Bahire Filiz , Yavuz Erdem
Published: November 2006

Poly(vinyl pyrrolidone) was grafted onto crosslinked polystyrene beads through the 2‐chloroethyl sulfonamide (CSA) groups present in the resin using the atom transfer radical polymerization (ATRP) method. A beaded polymer with a poly(vinyl pyrrolidone) surface shell was prepared in three steps, starting from polystyrene‐divinylbenzene (10% crosslinking) based beads with a particle size of 420–590 μm, according to the synthetic protocol; chlorosulfonation, sulfamidation with 2‐chloroethylamine hydrochloride and grafting reaction of poly(vinyl pyrrolidone).

The polymeric resin prepared with the described procedure with 72.66% of grafted poly(vinyl pyrrolidone) has also been demonstrated to be an efficient dye sorbent, able to remove dye from water even at ppm levels. The dye sorption capacity under non‐buffered conditions is around 0.65 g dye/g resin. Copyright © 2006 John Wiley & Sons, Ltd.
Wood flour filled PP composites: adhesion, deformation, failure
Authors: Dányádi Lívia , Renner Károly , Szabó Zoltán , Nagy Gábor , Móczó János , Pukánszky Béla
Published: November 2006

Poly(propylene) (PP) wood composites were prepared in a wide composition range from 0 to 70 wt% wood content. Matrix/wood adhesion was improved by the introduction of two maleinated polypropylenes (MAPPs) with different molecular weights and functionality. MAPP/wood ratio changed from 0 to 0.25 in 0.05 steps. Mechanical properties of the composites were characterized by tensile testing, while their fracture resistance was determined with instrumented impact measurements. Micromechanical deformation processes were followed by acoustic emission and volume strain measurements, which were supported by scanning electron microscopy done on the broken surface of fractured samples. The results show that stiffness increases with wood content and it does not depend very much either on the type or the amount of the functionalized polymer used. However, ultimate tensile properties are strongly influenced by the amount and properties of MAPP; larger molecular weight and smaller functionality are more advantageous both for strength and impact resistance. The optimum MAPP/wood ratio was found to be around 0.05 in accordance with some literature data. Because of their large size, wood particles debond very easily from the matrix leading to volume increase and catastrophic failure at small deformations. When adhesion is improved by the introduction of MAPP, large wood particles fracture thus also contributing to the failure of the composite. At large wood content considerable aggregation of the particles may take place leading to inferior strength. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and swelling behavior of poly(2‐dimethylaminoethyl methacrylate‐co‐N‐hydroxymethyl acrylamide) hydrogels
Authors: Gürdağ Gülten , Çavuş Selva
Published: November 2006

Crosslinked poly(2‐(N,N‐dimethylamino)ethyl methacrylate‐co‐N‐hydroxymethyl acrylamide) poly(DMAEMA‐co‐NHMAAM) copolymers were synthesized using ammonium persulfate (APS)/N,N,N′,N′‐tetramethyl ethylenediamine (TEMED) as initiator/accelerator system in the presence of tetraethyleneglycol diacrylate (TEGDA) as crosslinker in water at 60°C. The effects of comonomer composition in the feed, pH of the swelling medium, and the temperature on the equilibrium swelling (ES) values of hydrogels were investigated. While the initial total monomer concentration was kept constant at 0.5 or 1 mol/l, the contents of APS and TEGDA in the feed were 1 mol% of the total monomers. ES values of DMAEMA‐NHMAAM gels increased with the increase in DMAEMA content in the feed. Although DMAEMA‐NHMAAM hydrogels containing up to 30 mol% were transparent in appearance, the presence of 40% DMAEMA in the copolymer worsened its transparency. ES values of the copolymer gels with high DMAEMA contents increased with both temperature and the pH of swelling medium. Copyright © 2006 John Wiley & Sons, Ltd.
Langhans giant cells from M. tuberculosis‐induced human granulomas cannot mediate mycobacterial uptake
Authors: Lay G , Poquet Y , Salek‐Peyron P , Puissegur M‐P , Botanch C , Bon H , Levillain F , Duteyrat J‐L , Emile J‐F , Altare F
Published: November 2006

Tuberculosis is characterized by a tight interplay between Mycobacterium tuberculosis (M. tb) and host cells within granulomas. These cellular aggregates restrain M. tb spreading but do not kill all bacilli, which persist for years. A more detailed investigation of the interaction between M. tb and granuloma cells is needed to improve our understanding of this persistence and to explain the physiopathology of tuberculosis. In the present study, a recently developed in vitro human model of tuberculous granulomas has been used to analyse the modulation of granuloma cell differentiation by M. tb, in comparison to poorly virulent mycobacteria, which do not persist. It is reported that whilst all mycobacteria species induce granuloma formation, only M. tb triggers the differentiation of granuloma macrophages into very large multinucleated giant cells (MGCs) that are unable to mediate any bacterial uptake. This loss of function is not due to cell quiescence, as MGCs still display NADPH oxidase activity, but it correlates with decreased expression of phagocytosis receptors. This phenomenon is specific for the virulent species of M. tuberculosis complex, as poorly virulent species only induce the formation of small multinucleated cells (MCs) with conserved mycobacterial uptake ability, which never reach the MGC differentiation stage. The phenotype of MGCs thus strongly resembles mature dendritic cells with a loss of microbial uptake ability, despite conserved antigen presentation. In M. tb‐induced granulomas, MGCs thus seem to be devoted to the destruction of bacilli that have been ingested in previous differentiation stages, ie in macrophages and MCs. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Gallbladder disease in the general population: association with cardiovascular morbidity and therapy
Authors: González‐Pérez BPharm Antonio , García Rodríguez Luis A.
Published: November 2006

Purpose

Both gallbladder (GB) and cardiovascular disease are very common diagnoses that carry substantial economic costs. Prior studies suggest that personal history of ischaemic heart disease (IHD) could determine the occurrence of GB disease. Additionally the use of thiazide diuretics may also be a risk factor for this condition. We aimed to evaluate different cardiovascular conditions and related drugs that could be associated with GB disease.

Methods

We identified all incident cases of gallbladder disease occurring during 1996 among patients aged 20–79 years old registered in the General Practitioner Research Database. We performed a nested case control analysis using 2353 cases and 10 000 controls frequency matched to the cases by age and sex.

Results

After adjusting for potential confounders IHD was associated with a small increased risk of GB disease (1.29, 95%CI:1.08–1.55). When only cases requiring cholecystectomy were considered in the analysis, the resulting estimate was 1.06 (95%CI:0.83–1.35). Users of thiazide diuretics presented an OR of 1.36 (95%CI:1.08–1.71). Other antihypertensive drugs were not associated with GB disease.

Conclusions

Our results confirm the small increased risk of GB disease associated with thiazide diuretics. On the other hand, our data do not support a major association between IHD and GB disease. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and characterization of novel poly(γ‐benzyl‐L‐glutamate) derivatives tailored for the preparation of nanoparticles of pharmaceutical interest
Authors: Barbosa Ma Elisa Martínez , Montembault Véronique , Cammas‐Marion Sandrine , Ponchel Gilles , Fontaine Laurent
Published: November 2006

Four poly(γ‐benzyl‐L‐glutamate) (PBLG) derivatives bearing at one end specific groups were synthesized by ring‐opening polymerization of the corresponding γ‐benzyl‐L‐glutamate N‐carboxyanhydride using different amine‐terminated initiators. These moieties were chosen to introduce, on demand, specific functionalities in nanoparticles of pharmaceutical interest. The PBLG and PBLG derivatives were characterized by 1H NMR, viscosimetry, Fourier transform infrared spectroscopy and differential scanning calorimetry. Nanoparticles smaller than 100 nm in diameter could be easily prepared from these PBLG derivatives by slight modification of a known nanoprecipitation technique. Copyright © 2006 Society of Chemical Industry
Nonisothermal crystallization behavior of a luminescent conjugated polymer, poly(9,9‐dihexylfluorene‐alt‐2,5‐didodecyloxybenzene)
Authors: Yang Gui‐Zhong , Chen Xiaolei , Xu Yan , Li Chun‐Zhong , Wu Peiyi , Liu Tianxi
Published: November 2006

The nonisothermal crystallization kinetics of poly(9,9‐dihexylfluorene‐alt‐2,5‐didodecyloxybenzene) (PF6OC12) from the melt were investigated using differential scanning calorimetry under different cooling rates. Several analysis methods were used to describe the nonisothermal crystallization behavior of PF6OC12. It was found that the modified Avrami method by Jeziorny was only valid for describing the early stage of crystallization but was not able to describe the later stage of PF6OC12 crystallization. Also, the Ozawa method failed to describe the nonisothermal crystallization behavior of PF6OC12. However, the method developed by combining the Avrami and Ozawa equations could successfully describe the nonisothermal crystallization kinetics of PF6OC12. According to the Kissinger method, the activation energy was determined to be 114.9 kJ mol−1 for the nonisothermal melt crystallization of PF6OC12. Copyright © 2006 Society of Chemical Industry
Magnetic behavior of polycarbosilazane FeII, FeIII and mixed‐valence FeII–III chloride metallopolymers
Authors: Ali Hamam Yaqoub , El Ghanem Hasan Moh'd , Mahmoud Arafa Issam , Said Moh'd Rida , aljarayish Ibrahim Abo
Published: November 2006

FeII, FeIII and mixed‐valence FeII–III chlorides were reacted with poly[N,N′‐bis(dimethylsilyl)ethylenedi‐ amine], [Si(CH3)2NHCH2CH2NH]n, to form the corresponding Fe‐polycarbosilazane macromolecular complexes. The average chain–chain spacing in these materials was estimated from X‐ray diffraction data and found to be 6.94, 7.29, 7.30 and 7.45 Å in metal‐free and FeII, FeIII and FeII–III‐containing polycarbosilazanes, respectively. This demonstrates that FeII, FeIII and FeII–III chlorides are encapsulated between the polycarbosilazane chains. The chain–chain expansions in the divalent FeII and trivalent FeIII chloride macromolecular complexes are comparable, but less than that in the FeII–III chloride analog, which suggests that different chain–chain packings exist in the mixed‐valence macromolecular complex. The magnetic properties of the resulting complexes were investigated by measuring the magnetization in magnetic fields up to 8 kOe and in the temperature range from liquid nitrogen temperature to room temperature. Copyright © 2007 Society of Chemical Industry