bluuebunny/crossref_metadata_2025 huggingface dataset:
Unique Effects of Cyclodextrins on the Formation and Colorimetric Transition of Polydiacetylene Vesicles
Authors: Kim Jong‐Man , Lee Joo‐Seob , Lee Ji‐Seok , Woo Sang‐Yoon , Ahn Dong June
Published: November 2005

Summary: The effects of cyclodextrins (CDs) on the formation and color changes of polymerized 10,12‐pentacosadiynoic acid (PCDA) vesicles have been investigated. The strategy used in this study focuses on three different stages in which the CDs can play a role. Among the cyclodextrins investigated, α‐CD had most prominent effect on the perturbation of the ordered structures of the PCDA vesicles. Solid precipitates, formed by the PCDA vesicles in the presence of α‐CD were shown to be PCDA ‐ α‐CD inclusion complexes by using DSC, FTIR and 1H NMR analysis. The results of studies using 4‐nitrophenol as an inhibitor and the consideration of inner and outer diameters of cyclodextrins have led to the conclusion that the color induced by the cyclodextrins is due to the formation of inclusion complexes with the polydiacetylene.

Photograph of the polydiacetylene liposomes after 1 h in the presence of 10 mM of the three different cyclodextrins in a HEPES buffer solution.

magnified image

Photograph of the polydiacetylene liposomes after 1 h in the presence of 10 mM of the three different cyclodextrins in a HEPES buffer solution.
Novel Network Polymeric Phthalocyanines: Synthesis and Characterization
Authors: Bilgin Ahmet , Yağcı Çiğdem , Yıldız Ufuk
Published: November 2005

Summary: New p‐xylylenebis‐(oxa‐thia‐propan) bridged metal‐free and metallophthalocyanine polymers were synthesized. The metal‐free phthalocyanine polymer (3) was prepared by the reaction of a tetranitrile monomer with 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in pentanol. Ni‐ and Co‐phthalocyanine polymers were prepared by reaction of the tetranitrile compound with the chlorides of Ni(II) and Co(II) in quinoline. Cu‐ and Zn‐phthalocyanine polymers were prepared by the reaction of the tetranitrile compound with the acetates of Cu(II) and Zn(II) and DBU in amyl alcohol. Yellow PbO and Fe(CO)5 were used to prepare Pb‐ and Fe‐analog polymers, respectively. The Co‐phthalocyanine polymer was also prepared using ethylene glycol instead of quinoline in the presence of the catalyst ammonium molybdate. (3) was chemically doped with iodine. The electrical conductivities of the polymeric phthalocyanines measured as gold sandwiches were found to be 10−9–10−7 S · cm−1 in a vacuum and in argon. The electrical conductivity of iodine doped metal‐free phthalocyanine (3a) was found to be approximately 57 times higher than that of the undoped version. The extraction ability of (3) was also evaluated in THF using transition metal picrates, such as Ag1+, Hg2+, Pb2+, Cd2+, Cu2+ and Zn2+. The extraction affinity of (3) for Ag1+ was found to be highest in the heterogeneous phase extraction experiments. All the novel compounds were characterized using elemental analysis, UV‐Vis, FT‐IR, NMR and MS spectral data and DSC.

Synthesis of new network polymeric phthalocyanines.

magnified image

Synthesis of new network polymeric phthalocyanines.
Synthesis of Propylene/1‐Butene Copolymers with Ziegler‐Natta Catalyst in Gas‐Phase Copolymerizations, 1
Authors: Silva Fabricio M. , Lima Enrique L. , Pinto José C. , McKenna Timothy F.
Published: November 2005

Summary: The appropriate choice of comonomers can be used to create a wide range of polymer properties, leading to considerable improvement of product performance. Experimental runs were performed to evaluate the effect of 1‐butene on the crystallinity, the melt temperature and the molecular weight distribution (MWD) of the final propylene/1‐butene copolymer resins. According to the results obtained, the melt temperature of the copolymer material can be reduced significantly compared to that of the polypropylene homopolymer. The incorporation of 1‐butene into the copolymer chain leads to a decrease of the sealing initiation temperatures of propylene polymer resins. GPC analyses of copolymer samples showed that 1‐butene concentration does not seem to significantly influence either the shape of the MWD or the polydispersity indexes for a given set of reaction conditions. Therefore, a family of propylene/1‐butene random copolymers grades can be successfully developed for gas phase processes for packaging and film applications.

magnified image
Silica/Polyamide Nanocomposite Synthesis via an Original Double Emulsification Process in Miniemulsion
Authors: Boutti Salima , Bourgeat‐Lami Elodie , Zydowicz Nathalie
Published: November 2005

Summary: A new method for the encapsulation of inorganic charges by an organic polymer by a reactive double emulsification process is proposed. This work is especially novel since it is highly unusual to encounter polymerization reactions in such a double emulsification process. Silica was first synthesized in cyclohexane using a sol–gel process in an inverse microemulsion in the presence of a non‐ionic surfactant (nonylphenyl ether polyoxyethylene), tetraethoxysilane, and concentrated ammonia. The coupling agent, 3‐aminopropyl triethoxysilane, was then grafted onto the surface of the silica nanoparticles. In a third step, direct miniemulsions were prepared from the microemulsion containing the functionalized silica nanoparticles. The miniemulsions were prepared using sodium dodecylsulfate as the surfactant and cetyl alcohol as the costabilizer. Finally, an interfacial polycondensation occurred between a diamine added to the external phase and sebacoyl chloride in solution in the dispersed phase. The formation of polyamide latexes was proven using infrared spectroscopy, and observation of the nanocomposites by transmission electron microscopy showed mean diameters of 100 nm.

TEM micrograph of silica/polyamide nanocomposite particles

magnified image

TEM micrograph of silica/polyamide nanocomposite particles
Unusual Intercalation of Cationic Smectite Clays with Detergent‐Ranged Carboxylic Ions
Authors: Chou Chih‐Cheng , Chiang Ming‐Li , Lin Jiang‐Jen
Published: November 2005

Summary: The organic intercalation of cationic smectite clays is achieved by using alkali salts of alkyl carboxylic acids, instead of using conventional quaternary ammonium salts as ionic exchanging agents. Various organic acid salts, such as CH3(CH2)16COO−Na+, can be incorporated into divalent montmorillonite (M2+‐MMT) with a 30–40 wt.‐% organic embedding and an X‐ray diffraction basal spacing of 43 Å from the pristine 10 Å. The intercalation is generalized for carboxylate salts of different alkyl lengths and for alkali metal ions, including sodium and potassium ions, but is specific for the divalent MMT clay. This new type of organic species for clay modification allows the preparation of organoclays in the absence of quaternary ammonium salts. It is proposed that the organic embedding is driven by the formation of a thermodynamically stable RCOO−/M2+/SiO− complex.

Graphical illustration of the carboxylic acid salt complex with the divalent cations on silicate K10.

magnified image

Graphical illustration of the carboxylic acid salt complex with the divalent cations on silicate K10.
Tuning the Reactivity of N,O,O,O‐Non‐Metallocene Catalysts for α‐Olefin Polymerization: Issues Related to Ligand Symmetry and Derivatization
Authors: Sudhakar Padmanabhan , Sundararajan Govindarajan
Published: November 2005

Summary: Titanium‐based precatalysts, bearing C3 or pseudo‐Cs symmetric aminotriol ligands, upon activation with methylaluminoxane, polymerize hex‐1‐ene to give polymers of high molecular weight, i.e., 50 000 and 600 000, respectively, with low dispersity, 1.2–1.4, and high isotacticity, 85–60%, depending on the overall symmetry of the precatalysts, but when one arm of the aminotriol ligands is methylated to yield C2 or meso aminodiol ligands, their corresponding titanium catalysts gave higher‐molecular‐weight polyhexenes, 300 000 to 250 000, with lower dispersities, 1.07–1.11, which possibly suggests living polymerization, with activities 200–500 times greater than that of the parent C3 and pseudo‐Cs catalysts.

magnified image
Investigation of Catalyst Fragmentation in Gas‐Phase Olefin Polymerisation: A Novel Short Stop Reactor
Authors: Silva Fabricio M. , Broyer Jean P. , Novat Christian , Lima Enrique L. , Pinto José C. , McKenna Timothy F.
Published: November 2005

Summary: A short stop reactor (SSR) was developed to study nascent particle morphology and reaction kinetics in the gas‐phase polymerisation of olefins on supported catalysts. It is shown that the SSR provides a useful means to look into important phenomena such as catalyst fragmentation and catalyst site activation and deactivation that take place during the very early stages of the heterogeneous polymerisation of olefins. New experimental results obtained from gas‐phase polymerisation of ethylene show that, depending on the type of catalyst system and on the reaction conditions, different kinds of morphologies can be obtained for the nascent polymer (e.g., cracks and folded chain). Experimental data also indicate that the growth of the polymer chains occur at a non‐steady state during the very early stages of the polymerisation.

SEM image showing the morphology of a polymer/catalyst particle after 2 seconds of polymerisation at 8 bars of ethylene on an MgCl2‐supported Ziegler‐Natta catalyst.

magnified image

SEM image showing the morphology of a polymer/catalyst particle after 2 seconds of polymerisation at 8 bars of ethylene on an MgCl2‐supported Ziegler‐Natta catalyst.
Electronic Properties and Field‐Effect Transistors of Thiophene‐Based Donor–Acceptor Conjugated Copolymers
Authors: Champion Richard D. , Cheng Kai‐Fang , Pai Chia‐Ling , Chen Wen‐Chang , Jenekhe Samson A.
Published: November 2005

Summary: The thiophene‐quinoxaline donor–acceptor conjugated copolymer poly[(thiophene‐2,5‐diyl‐alt‐(2,3‐diheptylquinoxaline‐5,8‐diyl)] (PTHQx) was explored as a semiconductor in thin‐film organic field‐effect transistors (OFETs). A hole mobility of 3.6 × 10−3 cm2 · V−1 · s−1 and an on/off current ratio of 6 × 105 were observed in p‐channel OFETs made from spin‐coated PTHQx thin films. The electronic structures of PTHQx and a related thiophene‐thienopyrazine donor–acceptor copolymer were calculated by density functional theory. Atomic force microscopy of PTHQx thin films showed a polycrystalline grain morphology that varied with the substrate.

Output (left) and transfer (right) characteristics of a PTHQx (structure shown) organic field‐effect transistor.

magnified image

Output (left) and transfer (right) characteristics of a PTHQx (structure shown) organic field‐effect transistor.
Inkjet Printing of Functional Polymers and Materials: 2nd International Workshop in Eindhoven
Authors: Tekin Emine , Schubert Ulrich S.
Published: November 2005

This section contains reports on topical conferences. Reports are usually written at the request of the editorial office, but unsolicited contributions are also welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de.
The role of mass spectrometry in plant systems biology
Authors: Glinski Mirko , Weckwerth Wolfram
Published: November 2005

Large‐scale analyses of proteins and metabolites are intimately bound to advancements in MS technologies. The aim of these non‐targeted “omic” technologies is to extend our understanding beyond the analysis of only parts of the system. Here, metabolomics and proteomics emerged in parallel with the development of novel mass analyzers and hyphenated techniques such as gas chromatography coupled to time‐of‐flight mass spectrometry (GC‐TOF‐MS) and multidimensional liquid chromatography coupled to mass spectrometry (LC‐MS). The analysis of (i) proteins (ii) phosphoproteins, and (iii) metabolites is discussed in the context of plant physiology and environment and with a focus on novel method developments. Recently published studies measuring dynamic (quantitative) behavior at these levels are summarized; for these works, the completely sequenced plantsArabidopsis thalianaandOryza sativa(rice) have been the primary models of choice. Particular emphasis is given to key physiological processes such as metabolism, development, stress, and defense. Moreover, attempts to combine spatial, tissue‐specific resolution with systematic profiling are described. Finally, we summarize the initial steps to characterize the molecular plant phenotype as a corollary of environment and genotype. © 2005 Wiley Periodicals, Inc. Mass Spec Rev 25:173–214, 2006
Phosphorus Dendrimers: Nano‐objects for Nanosciences
Authors: Majoral Jean‐Pierre , Turrin Cédric‐Olivier , Laurent Régis , Caminade Anne‐Marie
Published: November 2005

Summary: The influence of the size (the generation) of phosphorus dendrimers on their properties is discussed in three main fields of applications: catalysis, new materials, and biology. Typical examples are given to illustrate these three fields: Knoevenagel condensation for catalysis, elaboration of highly sensitive DNA chips for materials, transfection experiments, and anti‐prion activity for biology.
New Perspectives in Living/Controlled Anionic Polymerization
Authors: Deffieux Alain , Carlotti Stéphane , Desbois Philippe
Published: November 2005

Summary: Control of the reactivity and selectivity of active species remains a major challenge in the course of living/controlled polymerizations of vinyl and heterocyclic monomers. We have found that alkyl metal derivatives such as dialkylmagnesium or trialkylaluminum derivatives or the corresponding alkoxyakyl metal derivatives, when added to conventional anionic polymerization systems, are very effective mediators for the controlled anionic polymerization of both styrenic and oxirane monomers. When used as additives to alkali metal alkyl initiators (alkyl lithium, alkyl sodium) for the styrene anionic polymerizations, they strongly retard the reactivity of the propagating species and allow controlling the polymerization in very unusual conditions (bulk, very high temperature). On the contrary, when used in combination to the same alkali metal based initiators for the anionic polymerization of ethylene oxide or propylene oxide, these additives can drastically enhance the reactivity and the selectivity of the propagating species allowing a fast living‐like polymerization to proceed already at low temperature in hydrocarbon media.
Surface Assisted Nucleation and Growth of Polymer Latexes on Organically‐Modified Inorganic Particles
Authors: Bourgeat‐Lami Elodie , Herrera Norma Negrete , Putaux Jean‐Luc , Reculusa Stéphane , Perro Adeline , Ravaine Serge , Mingotaud Christophe , Duguet Etienne
Published: November 2005

Summary: Polymer latex particles were synthesized in the presence of inorganic particles, which had been organically‐modified to promote favorable interactions with growing macromolecules. The organic modification was performed using three different routes: (1) surface covalent grafting of vinyl trialkoxysilanes, (2) surface adsorption of polyethylene glycol‐based macromonomers, and (3) bulk modification through ion exchange with cationic monomers or cationic initiators. Two types of mineral particles were studied: commercial and self‐prepared silica particles (with diameters from 80 nm to 1 µm), and commercial laponite clay particles with a cation exchange capacity of 0.75 meq · g−1. Emulsion polymerization was performed in the presence of styrene or butyl acrylate monomers. The morphologies of the nanocomposite particles were observed by (cryogenic) transmission electron microscopy and correlated to the organic modification procedure.
Reactive Polymer Based Colloids for Biomedical Applications
Authors: Elaissari Abdelhamid
Published: November 2005

Summary: This short review aimed to give to the reader brief applications of polymer colloids in biomedical area and principally in medical diagnostics. Colloidal polymer particles are mainly used as solid supports, as label for biomolecules reactions detection, and as a carrier. The elaboration of appropriate colloids is reached via numerous processes such as polymerization in dispersed media (dispersion, emulsion, precipitation, miniemulsion polymerizations) or as physico‐chemical methodologies (i.e., self‐assembly). After a short introduction, some particles elaborations are presented and their applications are briefly described and illustrated.
Morphology and Structure of Crystalline Polysaccharides: Some Recent Studies
Authors: Putaux Jean‐Luc
Published: November 2005

Summary: In this paper, we review recent studies on the morphology and molecular structure of some polysaccharide crystals from amylose, cellulose, and mannan. The data were recorded using combinations of imaging, diffraction, and spectroscopic techniques: scanning and transmission electron microscopy, electron, neutron, and X‐ray diffraction, as well as 13C solid‐state NMR spectroscopy. Differences were generally found between native crystals, whose features result from in vivo biogenesis and the recrystallized products prepared in vitro.
Effect of Initiator on the Incorporation of Graphite into Polymer Matrix During Suspension Polymerization
Authors: Lopes Cristiane N. , Moreira Regina F. P. M. , Machado Ricardo A. F. , Araújo Pedro H. H.
Published: November 2005

Summary: The incorporation of graphite into polystyrene (PS) particles produced by suspension polymerization was studied using a monofunctional and a bifunctional initiator, benzoyl peroxide (BPO) and 2,5‐dimethyl‐2,5‐bis(2‐ethyl hexanoyl peroxide) hexane (L256), respectively. The results showed that the polymerization rate was affected by graphite concentration when BPO was used as the initiator while no such effect was observed for L256. Results also showed that the incorporation of graphite in the PS particles was higher when using BPO than when using L256. Molecular weight distribution showed that during the reaction with BPO and graphite oligomers were formed indicating that the free radicals generated by the decomposition of BPO presented a very high reactivity with the functional groups present at the graphite surface while no significant effect was observed for the reaction with L256.
Deriving Molecular Parameters of Interfaces Between Chemically Identical Polymers from Macroscopically Observed Phenomena
Authors: Reiter Günter
Published: November 2005

Summary: By utilizing model systems, macroscopically observable phenomena like friction or dewetting allow to identify and to quantify molecular interfacial parameters like molecular interpenetration depth, interfacial tension, or slippage length between grafted and free chemically identical polymers. We present experimental results, which permit to extract these parameters from simple contact angle measurements or by following the dewetting process in real time with a simple optical microscope. We also show how these model experiments can provide valuable insight and fundamental understanding of processes like polymeric friction and adhesion.
Polycaprolactone‐b‐Poly(ethylene oxide) Biocompatible Micelles as Drug Delivery Nanocarriers: Dynamic Light Scattering and Fluorescence Experiments
Authors: Giacomelli Cristiano , Lafitte Gabriel , Borsali Redouane
Published: November 2005

Summary:Dynamic light scattering (DLS) and fluorescence experiments were carried out to study PCL44‐b‐PEO114biocompatible micelles used as nanocarriers in drug delivery. Micelles prepared by a simple procedure (THF removal under nitrogen flow) exhibited a narrow size distribution with an average diameter of 100 nm. For micelles containing a hydrophobic model compound (pyrene) within the PCL core, a smaller average micellar size of 80 nm was observed, with a simultaneous broadening in the size distribution profile. In parallel to DLS results, fluorescence experiments showed evidence of pyrene encapsulation, and that the onset of the micellization process occurs at approximately 10/90 (v/v) THF/water mixtures in the case of PCL44‐b‐PEO114polymer.
Anthraquinone and Azo Dyes in Dyeing Processes of PET Films and PET Knitted Fabrics Using Supercritical CO2 Medium
Authors: Santos Washington L. F. , Moura Ana P. , Povh Nanci P. , Muniz Edvani C. , Rubira Adley F.
Published: November 2005

Summary: Dyeing processes using supercritical fluid present advantages over the conventional dyeing process using aqueous medium. Previous works from our group on polymeric fibers such as N,N‐dimethylacrylamide (DMAAm) modified poly(ethylene terephthalate), PET, showed higher sorption of disperse dyes in supercritical medium. Furthermore, recent studies showed that the association of UV radiation and DMAAm treatment leads to a better incorporation of dyes in modified PET soaked in aqueous medium. In this work, modified and non‐modified PET knitted fabrics (KF) were dyed in supercritical CO2 medium. Azo and anthraquinone dyes were used in order to compare the extent of incorporated dye in PET films and PET KF in supercritical CO2. The dyeing process variables were studied by factorial design and by a response surface methodology (RSM) technique. The anthraquinone dye presented a better incorporation in PET than the azo dye. The UV light exposure and the dyeing times inputs showed positive main effects in the incorporation of dyes in PET films and PET KF. From the RSM data, DMAAm and UV light modified PET KF presented 7.43 mg of incorporated azo dye by g of PET if the optimized dyeing conditions, time: 135 min and pressure: 212 bar would be used. In the respective optimized dyeing conditions for the anthraquinone dye, time 150 min and pressure 229 bar, the incorporated dye would be 22.9 mg of dye by g of PET.
Large Plastic Deformation of Isotactic Poly(propylene) (iPP) Evaluated by WAXD Techniques
Authors: Samios Dimitrios , Tokumoto Shinichi , Denardin Elton L. G.
Published: November 2005

Summary: Commercial isotactic poly(propylene) (iPP), obtained in bars, was annealed and submitted to different levels of plastic deformation by uniaxial plane compression using a special device which permits well controlled temperature and strain rate. The evolution of the microstructure was followed at different degrees of deformation by wide angle x‐ray diffraction (WAXD) techniques. The spherulite fragmentation process, lamellar orientation and destruction of the crystallites is argued, according to collected analytical data in the flow direction (FD), the loading direction (LD) and the lateral or constrain direction (CD). The evaluation of the WAXD patterns in terms of diffraction line position, intensity and width, permits to affirm that, while the large plastic deformation occurs, the crystalline net suffers anisotropic deformation, the crystallites become preferentially oriented along the flow direction and the crystalline phase diminish in amount indicating lesser and smaller crystallites. The gradual lamellae fragmentation occurs, starting with apparent crystalline size of approximately 30 nm for the non‐deformed material and gradually decreasing to approximately 15 nm for the 70% deformed one.
A New ESIPT Fluorescent Dye‐Doped Silica Aerogel
Authors: Rodembusch Fabiano Severo , Campo Leandra Franciscato , Rigacci Arnaud , Stefani Valter
Published: November 2005

Summary: A silyl‐functionalized benzazole dye, fluorescent by excited state intramolecular proton transfer (ESIPT) mechanism, was synthesized by reacting 2‐(2′‐hydroxyphenyl)benzoxazole with 3‐(triethoxysilyl)propyl isocyanate. The fluorescent silica gel was prepared by the addition of a solution of 2‐propanol and the fluorescent dye after the gelation time. The monolithic aerogel was obtained via supercritical CO2 drying of the fluorescent gel. The resulting aerogel is transparent in the visible light and fluorescent in the blue‐green region under UV radiation.
Synthesis and Characterization of Chiral [3,22]‐Ionenes
Authors: Bazito Reinaldo C. , Cássio Fernando L. , Quina Frank H.
Published: November 2005

Summary: Two [3,22]‐ionenes with pendent chiral groups, glucopyranosyl‐[3,22]‐ionene and β‐cyclodextrin‐[3,22]‐ionene, were synthesized by the reaction between the tosyl derivatives of the carbohydrate (methyl alpha‐glucopyranoside or beta‐cyclodextrin) and the tertiary [3,22]‐polyamine obtained by selective demethylation of [3,22]‐ionene. The derivatives were characterized by 1H NMR spectroscopy, presenting degrees of substitution of 30 and 45% for the glucosyl and cyclodextrin derivatives, respectively. It was shown by using pyrene as the fluorescent probe, that both polymers form hydrophobic domains, characteristic of micelle‐mimetic polysoaps in aqueous solution.
Competitive Process of Binding Between the Anionic Surfactants Sodium Dodecyl Sulfate and Sodium Cholate in Bovine Serum Albumin
Authors: Schweitzer Bianca , Felippe Arlindo C. , Dal Bó Alexandre , Minatti Edson , Zanette Dino
Published: November 2005

Summary: In this study sodium cholate (NaC) was used as a representative bile salt for the competitive binding between NaC and sodium dodecyl sulfate (SDS) in bovine serum albumin (BSA), in 0.02 M tris‐HCl buffer solution at pH 7.50 and 25 °C. The NaC and SDS associations with BSA were monitored at low surfactant concentrations where only this specific binding process can develop. The applied method to monitor the binding was based on the analysis of the effect of SDS and NaC concentrations and their mixtures upon the fluorescence intensity of the BSA tryptophan residues. This consists of the measurement of the surfactant monomer partitioning between the dispersion medium and the microaggregates on the protein molecule where the binding is indicated by the quenching of the fluorescence chromophores. Experimentally, varying the protein concentration, the surfactant concentration needed to reach a given Io/I ratio (Io and I are the intensities with and without protein, respectively) was measured. The analyses, based on the average number of surfactant molecules bound on the protein, indicated that the SDS is a more efficient quencher than the bile salt. The need for 4–6 NaC bound molecules to give the same protein quenching efficiency by a single molecule of SDS was estimated. We concluded that the differences in the competitive binding on the protein are exclusively related to the quenching efficiency in the formation of the nonfluorescent fluorophore‐quencher complex via a physical contact and static quenching process.
Carboxyl Terminated Polymer Chain Extension Using a Bisoxazoline Coupling Agent: Monte Carlo Simulation
Authors: Yan Li‐Tang , Xu Jun , Qian Zhen‐Yu , Guo Bao‐Hua , Xie Xu‐Ming
Published: November 2005

Summary: The kinetics of the chain extension reaction of a carboxyl‐terminated polymer using a bisoxazoline coupling agent was simulated by the Monte Carlo method based on the master equation. The effects of temperature and stepwise addition of the chain extender was examined. A comparison between simulated results and those calculated by an amended kinetic model was made. The results show that the highest coupling efficiency and the highest $\overline M _{\rm n}$ can be obtained when the initial concentrations of carboxyl and oxazoline groups are equal, which is in good agreement with the experiments. It is found that a higher reaction temperature could lead to a bigger coupling efficiency, a higher $\overline M _{\rm n}$ and narrower MWDs. The stepwise addition of the chain extender can only postpone the chain extension reaction, but cannot affect the final coupling efficiency and the MWDs when the concentration of the oxazoline group is lower than that of the carboxyl group. However, stepwise addition of the chain extender favors bigger coupling efficiency and narrower MWDs when the concentration of the oxazoline group exceeds that of the carboxyl group.

The relationship among three group of polymers, r and ratios of k2 to k1. The dots are the data simulated by MC and solid lines are relative data calculated by the kinetic model.

magnified image

The relationship among three group of polymers, r and ratios of k2 to k1. The dots are the data simulated by MC and solid lines are relative data calculated by the kinetic model.
A new fuzzy multicriteria evaluation method for group site selection in GIS
Authors: Bailey David , Goonetilleke Ashantha , Campbell Duncan
Published: November 2005

Multiple criteria group site selection problems involve a group of individuals evaluating a set of alternative sites on the basis of multiple criteria. This paper presents an application of a new fuzzy algorithm for finding and exploring potential solutions to these problems in a raster Geographical Information System (GIS) environment. Linguistic assessments from decision‐makers are represented as triangular fuzzy numbers (TFN's), which are adjusted for uncertainty in the source data and their relationship to suitability by using an approach based on type‐2 fuzzy sets. The first aggregation of inputs is a compensatory one based on fuzzy multiattribute decision‐making (MADM) theory. An adjusted aggregation then factors in conflicts, risks and uncertainties to enable a variety of compensatory and non‐compensatory outcomes to be generated based on decision‐maker preferences. The algorithm was implemented in ArcView GIS as part of an ongoing collaborative project with Brisbane Airport. This paper outlines the fuzzy algorithm and its use in site selection for a recycling facility on the Brisbane Airport site. Copyright © 2005 John Wiley & Sons, Ltd.
Fuzzy MCDM based on the concept of α‐cut
Authors: Liang Gin‐Shuh , Ding Ji‐Feng
Published: November 2005

In a fuzzy multiple criteria decision‐making (MCDM) problem, with a hierarchical structure of more than two levels and involving multiple decision‐makers (DMs), to find the exact membership functions of the final aggregation ratings of all feasible alternatives is almost impossible. Thus, ranking methods based on exact membership functions cannot be utilized to rank the feasible alternatives and complete the optimal selection. To resolve the above‐mentioned complexity and to incorporate assessments of all DMs' viewpoints, in this paper a fuzzy MCDM method with multiple DMs, based on the concepts of fuzzy set theory and α‐cut, is developed. This method incorporates a number of perspectives on how to approach the fuzzy MCDM problem with multiple DMs, as follows: (1) combining quantitative and qualitative criteria as well as negative and positive ones; (2) using the generalized means to develop the aggregation method of multiple DMs' opinions; (3) incorporating the risk attitude index β to convey the total risk attitude of all DMs by using the estimation data obtained at the data input stage; (4) employing the algebraic operations of fuzzy numbers based on the concept of α‐cut to calculate the final aggregation ratings and develop a matching ranking method for proposed fuzzy MCDM method with multiple DMs. Furthermore, we use this method to survey the site selection for free port zone (FPZ) in Taiwan as an empirical study to demonstrate the proposed fuzzy MCDM algorithm. The result of this empirical investigation shows that the port of Kaohsiung, the largest international port of Taiwan as well as the sixth container port in the world in 2004, is optimal for the Taiwan government in enacting the plan of FPZ. Copyright © 2005 John Wiley & Sons, Ltd.
Sculpturing a fibular flap: Combined horizontal/vertical osteotomy and ostectomy for reconstruction of complex craniofacial defects with one flap
Authors: Okumus Ayhan , Emekli Ufuk , Kabakas Fatih , Kuvat Samet Vasfi , Aydin Atakan , Hafiz Günter , Aslanov Ayaz , Kesim Sinan Nur
Published: November 2005

A fibular flap has great versatility in reconstructive procedures. Osteomies and ostectomies enable the flap to be used for variable defects. We used combined horizontal/vertical osteotomy and ostectomy for reconstruction of complex craniofacial defects with one flap in two patients. Vertical osteotomy transforms the tubular structure of a fibula into a flat bone that can be used for reconstruction of wider defects with less vertical height. Neither vertical osteotomy nor ostectomy had negative effects on viability and bony healing of the segments in our patients. We think that the fibular flap, thanks to its versatility, can be used for reconstruction of complex orbito‐zygomatic and orbito‐cranial defects successfully. © 2005 Wiley‐Liss, Inc. Microsurgery 25:589–595, 2005.
Are mechanical microvascular anastomoses easier to learn than suture anastomoses?
Authors: Zdolsek Johann , Ledin Håkan , Lidman Disa
Published: November 2005

Sutured anastomoses of small vessels are considered difficult to learn. Mechanical anastomosis systems allow a more rapidly performed anastomosis. In order to compare the process of learning to perform sutured and mechanical microvascular anastomoses, two surgeons, with limited microvascular experience, performed 30 aortic and 30 femoral vein anastomoses in 30 Wistar rats. The methods compared were conventional suture, vascular closure system (VCS) and microvascular anastomatic coupler system (MAC). There were no intersurgeon differences regarding patency or time to perform anastomoses. The average time to perform a suture anastomosis was 39 min (patency 80%). Anastomoses with the VCS system took 24 min (patency 25%), whereas the MAC couplers took 13 min to perform (patency 95%). There was a significant learning effect with sutures, but no obvious reduction in time to perform MAC coupler or VCS clip anastomoses was seen. MAC couplers were easiest to use, and allowed us to perform rapid anastomoses with high patency. © 2005 Wiley‐Liss, Inc. Microsurgery 25:596–598, 2005.
Microsurgical training curriculum for learning kidney and liver transplantation in the rat
Authors: Hölzen Jens Peter , Palmes Daniel , Langer Martin , Spiegel Hans Ullrich
Published: November 2005

During the education of the next generation of scientists in experimental research, careful instruction in surgical techniques is of major importance. This applies in particular to complicated microsurgical models, which require a structured teaching concept with clearly laid‐down working steps and adequate didactic resources. Transplantations in rats are undoubtedly among the most difficult models in experimental surgery. Because completely sutured orthotopic liver transplantation and kidney transplantation have been practiced for many years in our Surgical Research Unit, techniques must be transmitted to future generations. A microsurgical training program has been set up with the aim of being efficient, transparent, and motivating. Simply learning‐by‐doing in the sense of “laissez‐faire” is ineffective and costly. Our training program is based on “three‐phase didactics,” in which the learning targets are presented in sequence and are clearly defined. This report is intended to give a brief overview of the principal transplantation models and to serve as a guide for teaching these models. © 2005 Wiley‐Liss, Inc. Microsurgery 25:614–623, 2005.
Reconstruction of foot defects with free lateral arm fasciocutaneous flaps: Analysis of fifty patients
Authors: Ulusal Betul Gozel , Lin Yu‐Te , Ulusal Ali Engin , Lin Chih‐Hung
Published: November 2005

In this article, long‐term outcomes of foot reconstruction with free lateral arm fasciocutaneous flaps were retrospectively analyzed in 50 patients. The patients, 38 men and 12 women, ranged in age from 7–73 years (mean, 43.5 years). Indications for surgery included trauma (32 patients), diabetes mellitus (7 patients), burns (7 patients), chronic ulcers (3 patients), and tumor (1 patient). The locations of defects were the dorsum (n = 21), ankle (n = 12), medial (n = 6), lateral (n = 6), posterior heel (n = 2), and distal sole (n = 3) Concomitant bone injury occurred in 5 cases, and the weight‐bearing surface of the foot was involved in 5 patients. Defects ranged in size from 27–76 cm2 (mean, 36.4 cm2). Successful reconstructions were accomplished in 46 cases (92%). Flap complications included total flap loss and below‐knee amputation (1 patient) and partial flap loss (3 patients); 75% (3/4) of these cases had diabetes as a comorbid factor, and 25% (1/4) had a concomitant bone injury. Six patients with dorsum defects required debulking of the flap (11.1%). None of the patients required modified shoes. In the majority of cases, flaps provided stable coverage and a gain in protective deep‐pressure sensation. In long‐term follow‐up (up to 4 years), patients regained their ambulation, free of pain. Even in weight‐bearing areas, none of the cases experienced ulceration or skin breakdown. Free lateral arm flaps provided excellent durability, with solid bony union and successful restoration of the contour of the foot in moderate‐sized foot defects. © 2005 Wiley‐Liss, Inc. Microsurgery 25:581–588, 2005.
B1 destructive interferences and spatial phase patterns at 7 T with a head transceiver array coil
Authors: Van de Moortele Pierre‐François , Akgun Can , Adriany Gregor , Moeller Steen , Ritter Johannes , Collins Christopher M. , Smith Michael B. , Vaughan J. Thomas , Uğurbil Kāmil
Published: November 2005

RF behavior in the human head becomes complex at ultrahigh magnetic fields. A bright center and a weak periphery are observed in images obtained with volume coils, while surface coils provide strong signal in the periphery. Intensity patterns reported with volume coils are often loosely referred to as “dielectric resonances,” while modeling studies ascribe them to superposition of traveling waves greatly dampened in lossy brain tissues, raising questions regarding the usage of this term. Here we address this question experimentally, taking full advantage of a transceiver coil array that was used in volume transmit mode, multiple receiver mode, or single transmit surface coil mode. We demonstrate with an appropriately conductive sphere phantom that destructive interferences are responsible for a weak B1 in the periphery, without a significant standing wave pattern. The relative spatial phase of receive and transmit B1 proved remarkably similar for the different coil elements, although with opposite rotational direction. Additional simulation data closely matched our phantom results. In the human brain the phase patterns were more complex but still exhibited similarities between coil elements. Our results suggest that measuring spatial B1 phase could help, within an MR session, to perform RF shimming in order to obtain more homogeneous B1 in user‐defined areas of the brain. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Tissue segmentation and classification of MRSI data using canonical correlation analysis
Authors: Laudadio Teresa , Pels Pieter , De Lathauwer Lieven , Van Hecke Paul , Van Huffel Sabine
Published: November 2005

In this article an accurate and efficient technique for tissue typing is presented. The proposed technique is based on Canonical Correlation Analysis, a statistical method able to simultaneously exploit the spectral and spatial information characterizing the Magnetic Resonance Spectroscopic Imaging (MRSI) data. Recently, Canonical Correlation Analysis has been successfully applied to other types of biomedical data, such as functional MRI data. Here, Canonical Correlation Analysis is adapted for MRSI data processing in order to retrieve in an accurate and efficient way the possible tissue types that characterize the organ under investigation. The potential and limitations of the new technique have been investigated by using simulated as well as in vivo prostate MRSI data, and extensive studies demonstrate a high accuracy, robustness, and efficiency. Moreover, the performance of Canonical Correlation Analysis has been compared to that of ordinary correlation analysis. The test results show that Canonical Correlation Analysis performs best in terms of accuracy and robustness. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Three‐dimensional reconstruction of limited‐view projections for contrast‐enhanced magnetic resonance angiography at high temporal and spatial resolution
Authors: Huang Yuexi , Gurr David , Wright Graham A.
Published: November 2005

The feasibility of reconstructing three‐dimensional (3D) MRI data sets from limited‐view projections is investigated in phantom and in vivo animal studies to improve the temporal resolution of magnetic resonance angiography without sacrificing spatial resolution. Thirty‐two pairs of orthogonal biplane projections are acquired in an interleaved manner during the first pass of a contrast agent. The full data set is reconstructed as a priori 3D information. Each pair of projections is then reconstructed into an individual 3D data set based on a correlation analysis with the a priori data set. In this way, time‐resolved 3D data sets at 1‐ to 2‐s time intervals are reconstructed with submillimeter spatial resolution. Artifacts are limited if the image is simply structured or sparse and if SNR is sufficient in the projection images. With this technique, both high temporal and spatial resolution can be achieved simultaneously. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Evidence for MHC I–restricted CD8+ T‐cell–mediated immunopathology in canine masticatory muscle myositis and polymyositis
Authors: Neumann J. , Bilzer T.
Published: November 2005

Masticatory muscle myositis (MMM) is the most common inflammatory myopathy (IM) in dogs, associated with antibodies against myosin. To further elucidate the immunopathogenesis, we investigated muscles of 53 dogs with MMM, 32 dogs with polymyositis (PM), and 4 dogs suffering from both, with regard to the presence and location of CD4+ and CD8+T cells, B cells, macrophages, major histocompatibility complex (MHC) class I and class II antigens, and autoantibodies. CD8+T cells were found in MMM (91%) and PM (75%), mostly paralleled (68% and 61%) by enhanced expression of MHC class I antigen on muscle fibers. CD8+T cells invading intact and neighboring necrotic muscle fibers were present in MMM (39%) and PM (42%). Dogs with MMM lacking intramuscular (26%) and circulating (36%) autoantibodies also had CD8+ T‐cell infiltrations and muscle‐fiber lesions. Since MHC class I antigen and CD8+ T cells were detected in the presence of CD4+ T cells, regardless of antimuscular antibodies, we consider MMM and PM in the dog as a CD8+ T‐cell–mediated immunopathological disease that initiates muscle‐fiber destruction and leads to production of myosin autoantibodies. Muscle Nerve 2006
An alternative test of electromyographic normalization in patients
Authors: Hsu Wei‐Li , Krishnamoorthy Vijaya , Scholz John Peter
Published: November 2005

The value of electromyography (EMG) in the interpretation of normal and pathological movement depends on recording, processing, and normalization procedures. Traditionally, maximum voluntary isometric contraction (MVIC) of individual muscles is commonly used for EMG normalization. However, this is a time‐ and energy‐consuming procedure, especially in patients. The aim of the present study was to compare an alternative method of recording the MVIC of lower‐limb muscles to the traditional method in healthy, young subjects as well as individuals with a stroke. The alternative method consisted of recording the maximum effort of several thigh and leg muscles simultaneously using two tasks on a dynamometer. Five healthy subjects and five individuals who had a stroke performed both MVIC tasks. The healthy group repeated the test 3 h later on the same day. In general, the method of computing maximum EMG from the alternative MVIC test yielded values that were equal or greater than those from the traditional test in both groups. In the healthy group, muscles showed similar EMGs in the two sessions, indicating that the test was reliable. These results suggest that the less time‐consuming alternative method of computing maximum EMG values used here provides a reasonable alternative when time and fatigue become issues, especially when testing patient populations. Muscle Nerve, 2006
A branch‐and‐price algorithm for parallel machine scheduling with time windows and job priorities
Authors: Bard Jonathan F. , Rojanasoonthon Siwate
Published: November 2005

This paper presents a branch‐and‐price algorithm for scheduling n jobs on m nonhomogeneous parallel machines with multiple time windows. An additional feature of the problem is that each job falls into one of ρ priority classes and may require two operations. The objective is to maximize the weighted number of jobs scheduled, where a job in a higher priority class has “infinitely” more weight or value than a job in a lower priority class. The methodology makes use of a greedy randomized adaptive search procedure (GRASP) to find feasible solutions during implicit enumeration and a two‐cycle elimination heuristic when solving the pricing subproblems. Extensive computational results are presented based on data from an application involving the use of communications relay satellites. Many 100‐job instances that were believed to be beyond the capability of exact methods, were solved within minutes. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Polynomial‐time approximation schemes for two‐machine open shop scheduling with nonavailability constraints
Authors: Kubzin M.A. , Strusevich V.A. , Breit J. , Schmidt G.
Published: November 2005

This paper addresses a two‐machine open shop scheduling problem, in which the machines are not continuously available for processing. The processing of an operation affected by a non‐availability interval can be interrupted and resumed later. The objective is to minimize the makespan. We present two polynomial‐time approximation schemes, one of which handles the problem with one non‐availability interval on each machine and the other for the problem with several non‐availability intervals on one of the machines. Problems with a more general structure of the non‐availability intervals are not approximable in polynomial time within a constant factor, unless $\cal{P = NP}$. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006
The simple boundary element method for multiple cracks in functionally graded media governed by potential theory: a three‐dimensional Galerkin approach
Authors: Paulino Glaucio H. , Sutradhar Alok
Published: November 2005

The simple boundary element method consists of recycling existing codes for homogeneous media to solve problems in non‐homogeneous media while maintaining a purely boundary‐only formulation. Within this scope, this paper presents a ‘simple’ Galerkin boundary element method for multiple cracks in problems governed by potential theory in functionally graded media. Steady‐state heat conduction is investigated for thermal conductivity varying either parabolically, exponentially, or trigonometrically in one or more co‐ordinates. A three‐dimensional implementation which merges the dual boundary integral equation technique with the Galerkin approach is presented. Special emphasis is given to the treatment of crack surfaces and boundary conditions. The test examples simulated with the present method are verified with finite element results using graded finite elements. The numerical examples demonstrate the accuracy and efficiency of the present method especially when multiple interacting cracks are involved. Copyright © 2005 John Wiley & Sons, Ltd.
A hybrid regularization method for inverse heat conduction problems
Authors: Ling Xianwu , Cherukuri H. P. , Horstemeyer M. F.
Published: November 2005

This paper presents a hybrid regularization method for solving inverse heat conduction problems. The method uses future temperatures and past fluxes to reduce the sensitivity to temperature noise. A straightforward comparison technique is suggested to find the optimal number of the future temperatures. Also, an eigenvalue reduction technique is used to further improve the accuracy of the inverse solution. The method provides a physical insight into the inverse problems under study. The insight indicates that the inverse algorithm is a general purpose algorithm and applicable to various numerical methods (although our development was based on FEM), and that the inverse solutions can be obtained by directly extending Stolz's equation in the least‐squares error (LSE) sense. Direct extension of the present method to the inverse internal heat generation problems is made. Four numerical examples are given to validate the method. The effects of the future temperatures, the past fluxes, the eigenvalue reduction, the varying number of future temperatures and local iterations for non‐linear problems are studied. Copyright © 2005 John Wiley & Sons, Ltd.