bluuebunny/crossref_metadata_2025 huggingface dataset:
Photorheology of Fast UV‐Curing Multifunctional Acrylates
Authors: Schmidt Lars E. , Leterrier Yves , Vesin Jean‐Marc , Wilhelm Manfred , Månson Jan‐Anders E.
Published: November 2005

Summary: The fast photopolymerization of different multifunctional acrylates was analyzed by means of photorheology. The materials studied included a penta/hexaacrylate monomer and two different acrylated hyperbranched polymers. The sensitivity of the commercial rheometer was improved several‐fold, by a combination of an adaptive filter algorithm and improved data treatment, using powerful oversampling acquisition hardware. The novel set‐up was capable of monitoring up to a five orders of magnitude increase in shear modulus within short experiment timescales (about 10 s). The improvement in sensitivity and acquisition rate enabled the induction time, gelation, and vitrification of the multifunctional acrylates to be determined. In addition, the influence of UV intensity on stiffness build‐up within these materials was studied. In the case of the penta/hexaacrylate system, gelation and vitrification were detected as distinct events, in contrast to the second‐generation hyperbranched polyester, for which vitrification could not be identified. These findings are related to the difference in the glass transition temperature of the cured networks.

Absolute value of the complex shear modulus as a function of time for different acrylate monomers during UV curing.

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Absolute value of the complex shear modulus as a function of time for different acrylate monomers during UV curing.
Lazard's Theorem forS‐posets
Authors: Bulman‐Fleming Sydney , Laan Valdis
Published: November 2005

In 1971, inspired by the work of Lazard and Govorov for modules over a ring, Stenström proved that the strongly flat right actsASover a monoidS(that is, the acts that are directed colimits of finitely generated free acts) are those for which the functorAS⊗ (from the category of leftS‐acts into the category of sets) preserves pullbacks and equalizers. He also provided interpolation‐type conditions (now referred to in the literature as Property (P) and Property (E)) characterizing strong flatness. Unlike the situation for modules over a ring, strong flatness is strictly stronger than (mono‐) flatness (wherein the functorAS⊗ is required only to preserve monomorphisms). The study of flatness properties of partially ordered monoids acting on partially ordered sets was initiated by S. M. Fakhruddin in the 1980s, and has been continued recently in the paper “Indecomposable, projective, and flatS‐posets” by Shi, Liu, Wang, and Bulman–Fleming, Comm. Algebra33, 235–251 (2005). In that paper, a criterion for the equality of elements in a tensor product ofS‐posets is given and a version of Property (P) is presented that, as in the unordered case, implies flatness and is implied by projectivity. The present paper introduces a corresponding Property (E) and establishes an analogue of the Lazard–Govorov–Stenström theorem in the context ofS‐posets. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pointwise estimates for Green's kernel of a mixed boundary value problem to the Stokes system in a polyhedral cone
Authors: Maz'ya V. , Rossmann J.
Published: November 2005

The paper deals with a mixed boundary value problem for the Stokes system in a polyhedral cone. Here different boundary conditions (in particular, Dirichlet, Neumann, free surface conditions) are prescribed on the sides of the polyhedron. The authors obtain regularity results for weak solutions in weighted L 2 Sobolev spaces and prove point estimates of Green's matrix. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a class of quasilinear eigenvalue problems in RN
Authors: Kristály Alexandru , Varga Csaba
Published: November 2005

We study an eigenvalue problem in RN which involves the p ‐Laplacian (p > N ≥ 2) and the nonlinear term has a global (p – 1)‐sublinear growth. The existence of certain open intervals of eigenvalues is guaranteed for which the eigenvalue problem has two nonzero, radially symmetric solutions. Some stability properties of solutions with respect to the eigenvalues are also obtained. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A New Approach to Thick Films of a Block Copolymer with Ordered Surface Structures
Authors: Han Xia , Xu Jian , Liu Honglai , Hu Ying
Published: November 2005

Summary: A unique and simple method to prepare films with various ordered nanoscopic cylindrical patterns on the surface is reported. Various solutions of gemini surfactants with different spacers were used as a nanotemplate, on which thick polymer films were fabricated by the supramolecular assembly of a native or chemically modified polystyrene‐block‐poly(ethylene/butylene)‐block‐polystyrene (SEBS) triblock copolymer. At the air/polymer surface, normal oriented cylindrical nanodomains formed by poly(ethylene/butylene) (PEB) block associates surrounded by polystyrene (PS) blocks are exhibited. While at the polymer/surfactant solution interface, parallel cylindrical nanodomains formed by PEB block stripes alternating with PS block stripes are observed. The ordered structure of the surface can be adjusted by changing the surfactant and the chemical nature of the polymer. In a special case using Gemini 16‐1‐Ph‐1‐16 and SEBS chemically modified with 2 wt.‐% maleic anhydride, a nearly perfect hexagonal ordered structure is obtained.

The AFM micrograph and associated FFT (inset) of the morphology of a SEBS thick film formed on a 16‐1‐Ph‐1‐16 solution to give a nearly perfect hexagonal ordered structure.

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The AFM micrograph and associated FFT (inset) of the morphology of a SEBS thick film formed on a 16‐1‐Ph‐1‐16 solution to give a nearly perfect hexagonal ordered structure.
Super‐Hydrophobic PDMS Surface with Ultra‐Low Adhesive Force
Authors: Jin Meihua , Feng Xinjian , Xi Jinming , Zhai Jin , Cho Kilwon , Feng Lin , Jiang Lei
Published: November 2005

Summary: Rough polydimethylsiloxane (PDMS) surface containing micro‐, submicro‐ and nano‐composite structures was fabricated using a facile one‐step laser etching method. Such surface shows a super‐hydrophobic character with contact angle higher than 160° and sliding angle lower than 5°, i.e. self‐cleaning effect like lotus leaf. The wettabilities of the rough PDMS surfaces can be tunable by simply controlling the size of etched microstructures. The adhesive force between etched PDMS surface and water droplet is evaluated, and the structure effect is deduced by comparing it with those own a single nano‐ or micro‐scale structures. This super‐hydrophobic PDMS surface can be widely applied to many areas such as liquid transportation without loss, and micro‐pump (creating pushing‐force) needless micro‐fluidic devices.

Etched PDMS surface containing micro‐, submicro‐, and nano‐composite structures shows a self‐cleaning effect with water CA as high as 162° and SA lower than 5°.

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Etched PDMS surface containing micro‐, submicro‐, and nano‐composite structures shows a self‐cleaning effect with water CA as high as 162° and SA lower than 5°.
Thermoswitchable Electronic Properties of a Gold Nanoparticle/Hydrogel Composite
Authors: Zhao Xiuli , Ding Xiaobin , Deng Zhenghua , Zheng Zhaohui , Peng Yuxing , Long Xinping
Published: November 2005

Summary: A well‐dispersed gold nanoparticle/poly(N‐isopropylacrylamide) (PNIPAm) hydrogel nanocomposite with thermoswitchable electrical properties is prepared by the copolymerization of functional Au nanoparticles with N‐isopropylacrylamide. It is found that the electrical conductivity of the nanocomposite changes by two orders of magnitude at moderate temperature (Ttran) upon temperature stimuli. The change of electrical properties is reversible during a heating and cooling cycle.

Schematic illustration of the mechanism of the thermo‐switchable electronic properties of the Au nanoparticle/PNIPAm composite.

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Schematic illustration of the mechanism of the thermo‐switchable electronic properties of the Au nanoparticle/PNIPAm composite.
Low‐Temperature Growth of Thick Polystyrene Brushes via ATRP
Authors: Samadi Azadeh , Husson Scott M. , Liu Yong , Luzinov Igor , Michael Kilbey S.
Published: November 2005

Summary: This contribution describes the graft polymerization of polystyrene (PS) by atom transfer radical polymerization at 50, 60, and 75 °C. Thick PS brushes were grown from initiator‐functionalized PGMA layers on silicon, and constant growth rates provide indirect evidence that the polymerizations were controlled.

Formation of polystyrene brushes at T < Tg by ATRP of styrene from α‐bromoester initiator‐functionalized poly(glycidyl methacrylate) layers.

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Formation of polystyrene brushes at T < Tg by ATRP of styrene from α‐bromoester initiator‐functionalized poly(glycidyl methacrylate) layers.
Cover Picture: Macromol. Rapid Commun. 22/2005
Authors: Wei Zhenli , Wu Jialong , Pan Qinmin , Rempel Garry L.
Published: November 2005

Cover: The spectra on the cover show the selective and quantitative hydrogenation of the carbon‐carbon double bonds in nitrile butadiene rubber, which provides evidence for the successful hydrogenation of nitrile butadiene rubber in latex form in the absence of any organic solvent. Details can be found in the Communication by Z. Wei, J. Wu, Q. Pan,* and G. L. Rempel* on page 1768.
Automated protein identification by tandem mass spectrometry: Issues and strategies
Authors: Hernandez Patricia , Müller Markus , Appel Ron D.
Published: November 2005

Protein identification by tandem mass spectrometry (MS/MS) is key to most proteomics projects and has been widely explored in bioinformatics research. Obtaining good and trustful identification results has important implications for biological and clinical work. Although well matured, automated software identification of proteins from MS/MS data still faces a number of obstacles due to the complexity of the proteome or procedural issues of mass spectrometry data acquisition. Expected or unexpected modifications of the peptide sequences, polymorphisms, errors in databases, missed or non‐specific cleavages, unusual fragmentation patterns, and single MS/MS spectra of multiple peptides of the same m/z are so many pitfalls for identification algorithms. A lot of research work has been carried out in recent years that yielded new strategies to handle a number of these issues. Multiple MS/MS identification algorithms are now available or have been theoretically described. The difficulty resides in choosing the most adapted method for each type of spectra being identified. This review presents an overview of the state‐of‐the‐art bioinformatics approaches to the identification of proteins by MS/MS to help the reader doing the spadework of finding the right tools among the many possibilities offered. © 2005 Wiley Periodicals, Inc. Mass Spec Rev 25:235–254, 2006
Controlled Radical Polymerization of N‐Vinylpyrrolidone by Reversible Addition‐Fragmentation Chain Transfer Process
Authors: Devasia Renjith , Bindu Raveendra L. , Borsali Redouane , Mougin Nathalie , Gnanou Yves
Published: November 2005

Summary: Poly(N‐vinylpyrrolidone) (PNVP) was polymerized by RAFT process using diphenyldithiocarbamate of diethylmalonate (DPCM) as the reversible chain transfer agent in the presence of a small percentage of a conventional radical initiator (AIBN). The molar mass of the polymers synthesized by this method was found to increase with conversion and time. The presence of end group in the polymer chain could be confirmed by 1H NMR spectra. The molar masses calculated using 1H NMR spectroscopy and static light scattering (SLS) showed good agreement with the theoretical molar masses. The RAFT compound was fully consumed during the initial stages of the polymerization itself. The controlled nature of these polymers was further confirmed by generating diblock copolymers by sequential addition of monomers such as styrene or n‐butyl acrylate (n‐BA). PNVP efficiently participated as a macro‐RAFT reagent, and cross‐over reaction between the two blocks efficiently occurred. The successful diblock copolymer synthesis using PNVP as macro‐transfer reagent further confirms the “controlled” nature of such synthetic procedure.
Dynamics of Biological Polyelectrolytes
Authors: Pecora R.
Published: November 2005

Summary: Biological polymers and structures, including proteins and DNAs, can be made in essentially monodisperse form. Proteins usually have well‐defined shapes. Duplex oligonucleotides are rigid and rodlike, and longer DNAs are semiflexible coils. The DNAs also constitute a homologous series. The dynamics of both proteins and DNAs can be studied by readily available techniques such as dynamic light scattering (DLS) and fluorescence correlation spectroscopy (FCS). These systems can thus be used as model systems to elucidate elusive charge effects on the dynamics of macromolecules in solution (polyelectrolyte effects) for both rigid and semiflexible polymers. We present here as examples the results of measurements of mutual and self‐diffusion coefficients dynamics of a rodlike oligonucleotide as functions of polymer concentration and the concentration of added salt (which screens the charges).
Hydroxy and Di‐Hydroxy End‐Capped Polybutadiene as Reactive Steric Stabilizers for the Synthesis of Polyurethane Particles in Organic Dispersant Media
Authors: Radhakrishnan Bindushree , Balerdi Goretti , Cloutet Eric , Cramail Henri
Published: November 2005

Summary: The synthesis of polyurethane particles by polyaddition of ethylene glycol (EG) and tolylene‐2,4‐diisocyanate (TDI) in cyclohexane at 60 °C was investigated in the presence of ω‐hydroxy and ω,ω′‐dihydroxy polybutadiene, used as reactive steric stabilizers. The effect of the functionality and concentration of the reactive polybutadiene, as well as the monomer addition procedure, onto the polyurethane particle formation was studied. Calibrated PUR particles with an average diameter in the range 1–2 µm could be readily obtained.
Microstructures Based on Thermotropic Liquid‐Crystalline Polymers in the Low Molar Mass Nematogenic 5CB
Authors: Pereira Fabiano V. , Zandoná Rodrigo , Borsali Redouane , Merlo Aloir A. , da Silveira Nadya P.
Published: November 2005

Summary: The unique characteristics of two polyacrylates having the same side chain chiral mesogenics groups and different spacer lengths allowed the stabilization of ordered polymer rich‐phases in solution with the nematic solvent 5CB. These microstructures are smectic having fibrous‐like and rode‐like morphologies, in spite of the mesophases of the polymers in bulk. The interactions between the mesogenic groups in the polymer and the solvent 5CB stabilize the microstructures and leads to birefringence at temperatures above the 5CB clearing point. Polarized optical microscopy data are complemented by SAXS to fully describe the mesomorphic behavior of the mixtures.
Tailoring the Flow Properties of Soft Colloidal Dispersions
Authors: Cloitre Michel
Published: November 2005

Summary: The dynamics and the non‐linear rheology of concentrated dispersions of soft particles are shown to exhibit generic properties. They display both solid‐like and liquid‐like properties depending on the applied stress. Below the yield point, dispersions exhibit history‐dependent phenomena that have all the hallmarks of ageing in glasses. The close‐packed disordered structures of the dispersions lie at the heart of this behaviour. Other properties such as the propensity of pastes to slip on solid surfaces appear to be governed by specific contact interactions between the squeezed particles.
Soy Protein Isolate Based Films: Influence of Sodium Dodecyl Sulfate and Polycaprolactone‐triol on Their Properties
Authors: Schmidt Vanessa , Giacomelli Cristiano , Soldi Marly S. , Soldi Valdir
Published: November 2005

Summary: We report on the preparation and properties of soy protein isolate (SPI)‐sodium dodecyl sulfate (SDS)‐polycaprolactone‐triol (PCL‐T) films obtained by solvent casting from solutions containing variable amounts of SDS or SDS/PCL‐T. It is shown that the mechanical and thermal properties, and the morphology of SPI‐based biofilms can be easily controlled by changing SDS, PCL‐T, and moisture contents, enabling the fabrication of rigid and flexible materials as pure SPI films [Young's modulus ∼ 1 400 MPa, elongation at break (E) ∼ 2%, and glass transition temperature (Tg) ∼ 150 °C] and SPI/SDS/PCL‐T films with [PCL‐T] ≥ 18% (Young's modulus ∼ 50 MPa, E ∼ 90%, and Tg ∼ 135 °C), respectively. Micrographs taken at the cross‐section of biofilms whose [PCL‐T] ≥ 18% revealed the occurrence of a porous matrix, whereas a dense bulk phase was otherwise observed (pure SPI, SPI/SDS, and SPI/SDS/PCL‐T films with [PCL‐T] < 18%).
Conducting Polymer‐Based Chemiresistive Sensor for Organic Vapours
Authors: Rosa Roberta M. , Szulc Ricardo L. , Li Rosamaria W. C. , Gruber Jonas
Published: November 2005

Summary:Poly(2‐bromo‐5‐hexyloxy‐p‐phenylenevinylene), BHPPV, was electrochemically synthesized in 81% yield. The polymer presented high solubility in organic solvents, in spite of its relatively high molar weight ($\overline{M}_{\rm w}$ = 80 000), and showed to be thermally resistant up to 130 °C. Gas sensors made from thin films of CSA doped BHPPV, deposited on interdigitated electrodes, responded to five different solvents. Plots of relative response versus relative recovery showed good discrimination of the five solvents.
Influence of the Addition of Lauric Acid to Films Made from Gelatin, Triacetin and a Blend of Stearic and Palmitic Acids
Authors: Canhadas Bertan Larissa , Matta Fakhouri Farayde , Siani Antonio Carlos , Ferreira Grosso Carlos Raimundo
Published: November 2005

Summary:The objective of this research was to verify the influence of adding increasing amounts of lauric acid on the functional properties of homogenized films made from gelatin, triacetin and a blend of palmitic and stearic acids. The films were characterised with respect to their visual aspect, water vapour permeability (WVP), water solubility, mechanical properties (tensile strength and percent elongation), oxygen permeability (O2P), opacity (OP) and melting and glass transitions temperatures. The films produced were malleable and macroscopically homogeneous. The addition of 1% of lauric acid to the film of gelatin, triacetin and blend of palmitic and stearic acids (5.84 ± 0.31 gmm · m−2dkPa) caused a slight decrease in WVP. The additions of 2.5% (5.70 ± 0.76 gmm · m−2dkPa), 5% (5.38 ± 0.64 gmm · m−2dkPa) and 10% (4.50 ± 0.55 gmm · m−2dkPa) of lauric acid were sufficient to make a significant difference in the WVP at the higher levels used. As compared to the gelatin and triacetin film, the addition of lauric acid at all the concentrations studied resulted in a slight increase in the film solubility. The addition of hydrophobic substances to gelatin/triacetin films (15.26 ± 0.28 cm3 · µm · m−2dkPa) favoured an increase in O2P permeability, this effect being greater in the films made from gelatin, triacetin, blend of palmitic and stearic acids and 10% lauric acid (24.48 ± 0.07 cm3 · µm · m−2dkPa). The increasing addition of lauric acid significantly reduced the tensile strength and increased elongation of the films composed of gelatin, triacetin and blend that being more evident at the concentrations of 5% (67.58 ± 1.23 MPa and 11.45 ± 0.57%) and 10% (63.50 ± 1.56 MPa and 12.90 ± 0.57%). The addition of 1% (OP, 27%) and 10% (OP, 28%) of lauric acid induced no visible effect on the opacity of the films. The thermogrammes showed three transitions for the gelatin/triacetin/stearic‐palmitic blend/1% lauric acid films (−57.42 °C, 23.74 °C and 44.11 °C) and two for the gelatin/triacetin/stearic‐palmitic acids blend/10% lauric acid films (−56.22 °C and 17.35 °C). As observed by DSC, the addition of fatty acids resulted in the appearance of more than one melting peak for all films in relation to the gelatin and triacetin film.
Rheological Behavior and Scattering Studies of Acrylamide‐Based Copolymer Solutions
Authors: Maia Ana M. S. , Costa Marta , Borsali Redouane , Garcia Rosangela B.
Published: November 2005

Summary:In this paper the chemical structure of an acrylamide‐N,N‐dihexylacrylamide copolymer was established by IR and NMR. Static and dynamic light scattering in formamide were used in order to evaluate the polymer structural parameters, such as weight‐average molecular weight (Mw), second virial coefficient (A2), radius of gyration (RG), the form factorP(q) and the hydrodynamic radius (RH). Additionally to the classical characterization, those results indicated the presence of aggregation, showing that formamide is not a very good solvent, as stated in earlier investigations. The rheological behavior in aqueous solutions was evaluated as a function of the salt concentration. The solutions presented an important viscosity increase in the presence of NaCl and did not show any sensitivity to the presence of CaCl2. This result is in favor of the oil recovery especially in high salinity reservoirs.
Preparation and Characterization of Poly(D,L‐Lactide) (PLA) and Poly(D,L‐Lactide)‐Poly(Ethylene Glycol) (PLA‐PEG) Nanocapsules Containing Antitumoral Agent Methotrexate
Authors: de Faria Tatiany J. , Machado de Campos Angela , Lemos Senna Elenara
Published: November 2005

Summary: The aims of the present work were to prepare and characterize nanocapsules containing antitumoral agent methotrexate (MTX) from poly(D,L‐lactide) (PLA) and poly(D,L‐lactide)‐poly(ethylene glycol) diblock copolymer (PLA‐PEG) with the purpose of administrating this drug by topical ocular route for primary ocular lymphoma treatment. Nanocapsules were prepared by the interfacial deposition of preformed polymer. The influences of the initial amount of MTX on the encapsulation efficiency, drug recovery and drug content, as well as the physicochemical properties of the particles were evaluated. The particle mean diameters were 246 and 146 nm, and zeta potential values were −38.8 and −33.6 mV, for the MTX‐loaded nanocapsules prepared from PLA and PLA‐PEG, respectively. The methotrexate content in the particles increased with the increasing in the drug amount added to the formulations, but the drug recovery decreased significantly. After 4 h of in vitro release, 28 and 86% of MTX was released from PLA and PLA‐PEG nanocapsules, respectively.
Use of Natural Monomer in the Synthesis of Nano‐ and Microparticles of Polyurethane by Suspension‐Polyaddition Technique
Authors: Zanetti‐Ramos Betina , Soldi Valdir , Lemos‐Senna Elenara , Borsali Redouane
Published: November 2005

Summary: Polyurethane nano‐ and microparticles were synthesized by suspension‐polyaddition technique, using aqueous polymerization medium. Castor oil, a vegetable triglyceride possessing hydroxyl groups was used as natural polyol and methylene diphenyl diisocyanate (MDI) as isocyanate. The levofloxacin, an antibacterial drug was used as model drug to measure the particles encapsulation efficiency. The effect of the addition of a second polyol, the poly(ethylene glycol) (PEG), and the stirring rate on the mean diameter and morphology of particles was also investigated. The poly(ethylene glycol) has an important effect in the reduction of particles size and their porosity. On the other hand, the poly(ethylene glycol) reduced the yield of encapsulation from 70% for the formulation without PEG to 20% for formulations with PEG. FTIR analysis confirmed the polyurethane formation. Dynamic light scattering study, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to determine the nanoparticles size and shape. Spectrofluorimetric analysis was used to detect the levofloxacin.
Malonylchitosan Microspheres as a Matrix for Oral Enrofloxacin Delivery
Authors: Valgas Saléte , Gonçalves Vanessa Lima , Laranjeira Mauro C. M. , Fávere Valfredo T. , Pedrosa Rozangela Curi
Published: November 2005

Summary: The purpose of this study was to produce malonylchitosan microspheres to be used as a pH sensitive matrix for the controlled delivery of drugs. Chitosan microspheres were obtained by the coacervation–phase separation method. The microspheres were then treated with malonic acid to obtain amidified chitosan microspheres. The resulting malonylchitosan microspheres were characterized by means of elemental analysis (CHN), infrared spectroscopy, conductometric titration and scanning electron microscopy (SEM). The data obtained from infrared spectroscopy, elemental analysis and conductometric titration of amino groups were consistent with the N‐substitution of malonyl groups in the chitosan microspheres. In vivo studies for controlled delivery of enrofloxacin were performed in male Wistar rats and the results indicated increase and prolonged blood levels with delayed peak and improved bioavailability for malonylchitosan microspheres compared to commercial tablets.
Effects of Neutralization Process on Preparation and Characterization of Chitosan Membranes for Wound Dressing
Authors: Nogueira Campos Maria Gabriela , Ferreira Grosso Carlos Raimundo , Cárdenas Galo , Inocentinni Mei Lucia Helena
Published: November 2005

Summary: Neutralization process effects on preparation and characterization of chitosan membranes were evaluated by differencial scanning calorimetry and scanning electron microscopy. Water solubility and humidity of chitosan membranes were also studied. Swelling behavior in different pH media was evaluated and mechanical properties such as tensile strength and elongation at break were measured. Neutralization process increased glass transition temperature of chitosan membranes and decreased their water solubility, humidity and water sorption. An improvement in mechanical properties of chitosan membranes was also observed after neutralization process.
Preparation and Characterisation of Thermoplastic Starches from Cassava Starch, Cassava Root and Cassava Bagasse
Authors: de Morais Teixeira Eliangela , Da Róz Alessandra Luzia , de Carvalho Antonio José Felix , da Silva Curvelo Antonio Aprigio
Published: November 2005

Summary: Thermoplastic starches (TPS) based on cassava starch have been produced by extrusion at 120 °C, using glycerol as plasticizer. Three forms of cassava starch were employed, viz: cassava root (CR), cassava bagasse (CB) and purified cassava starch (PCS). The main differences between these are the presence of sugars and a few fibres in CR and high fibre concentration in CB. Conditions of processing and characteristics such as amylose and fibre content, crystallinity, water absorption and mechanical behaviour in the tension x deformation test were evaluated. The results demonstrated that the PCS and CR had amylose contents consistent with literature values (14–18%) and that CB is a material constituted mainly by amylopectin. It was found that fibres in high proportions (as in the bagasse) can confer reinforcement properties and are thus able to generate natural composites of TPS with cellulose fibre. The sugars naturally found in the root reduce the elongation of the TPS under tension. The PCS and CR TPS were stable with respect to indices of crystallinity after processing; and during a period of 90 d in a relative humidity of 53%, while the CB TPS tended to vary its crystallinity, probably because its amylose chain had low degree of polymerization.
Miscibility and Mechanical Behavior of SAN/NBR Blends
Authors: Ziquinatti Francine , Hugen Roberson G. , Oliveira César M. , Coelho Luiz A. F. , Pezzin Sérgio H.
Published: November 2005

Summary: Aiming the development of high toughness polymer materials, blends of poly(styrene‐co‐acrylonitrile) (SAN) and poly(butadiene‐co‐acrylonitrile) (NBR) rubbers, with contents of acrylonitrile (AN) varying from 21 to 45%, were prepared by casting, coprecipitation and monoscrew extrusion followed by injection molding. SAN/NBR blends, prepared in the compositions (w/w) 90/10, 80/20, 70/30, 60/40, and 50/50, were characterized by differential scanning calorimetry (DSC) and Izod impact tests. DSC analyses showed that blends with 33% AN NBR prepared by casting, and with 39% AN NBR prepared by coprecipitation, are partially miscible at 60/40, 70/30 and 80/20 (SAN/NBR) compositions and immiscible for 50/50 compositions. On the other hand, 90/10 SAN/NBR systems were totally miscible. The blends with 45% AN NBR prepared by coprecipitation showed partial miscibility to 50/50, 60/40, 70/30 and 90/10 compositions and total miscibility to 80/20 composition. The NBR addition results in a significant increase in the impact resistance, strongly dependent on the blend composition and the NBR AN content. The best result of impact resistance — 75.2 ± 8.6 (kJ · m−2) — was obtained for SAN/NBR 50/50, using 45% AN NBR. This value is 15.7 times bigger than that for pure SAN ‐4.8 ± 0.7 (kJ · m−2).
Development of a Kinetic Model for Thermal Crosslinking of Rubbery Polymers
Authors: Vivaldo‐Lima Eduardo , Roa‐Luna Martha , Saldívar‐Guerra Enrique
Published: November 2005

Summary: A kinetic model for the thermal crosslinking of rubbery polymers is presented. The reaction mechanism used to develop the model includes thermal radical generation producing a polymeric radical and a primary radical, crosslinking from attack of a polymer radical to any inactive polymer molecule, bimolecular radical termination among chains of any degree of branching, and radical termination between a polymer radical and a primary radical from the thermal radical generation. The overall polymer population is divided into “generations”, which are defined in terms of the number of primary (linear) chains of original rubbery polymer attached to the polymer molecule. Mass balances for each generation are written down, and expressions to calculate fraction of branched molecules, gel fraction, and number and weight average chain lengths are derived. Model simulations, parameter sensitivity analyses and preliminary parameter estimation studies are presented, taking the thermal crosslinking of linear polybutadiene as a case study.

Development of a kinetic model for thermal crosslinking of rubbery polymers: reaction mechanism, model equations and parameter sensitivity analyses.

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Development of a kinetic model for thermal crosslinking of rubbery polymers: reaction mechanism, model equations and parameter sensitivity analyses.
A New Simulation Algorithm with Revised “Association Criteria” for Studying the Association of Heteroarm Star Copolymers
Authors: Havránková Jitka , Limpouchová Zuzana , Procházka Karel
Published: November 2005

Summary: A new computational algorithm for dynamic lattice Monte Carlo simulations of the associative behavior of heteroarm copolymers in selective solvents was developed and optimized for efficient and relatively fast simulation studies. The algorithm is based on the Siepmann and Frenkel variant of the bias self‐avoiding walk procedure. Simultaneously, a new criterion for recognition of an associate was proposed. The first results on the micellization of heteroarm star copolymers are presented.

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Prolonged limb allograft survival with CD40 costimulation blockade, T‐cell depletion, and megadose donor bone‐marrow transfusion
Authors: Tung Thomas H. , Mackinnon Susan E. , Mohanakumar T.
Published: November 2005

The purpose of this study was to determine the efficacy of a treatment regimen consisting of CD40 costimulation blockade, T‐cell depletion, and megadose donor bone marrow transfusion in the limb allograft model. C57Bl/6 mice underwent limb transplantation from Balb/c mice and received MR1 (anti‐CD40 ligand monoclonal antibody), and CD4+ and CD8+ T cell‐depleting antibodies with and without 120 × 106 donor bone‐marrow transfusion. Recipients treated only with antibodies showed rejection at 51.4 ± 17 (mean ± SEM) days, while those who also received donor bone marrow had allograft survival of 67 ± 16.4 days, with a range up to 91 days. Treated specimens with rejection had less lymphocytic infiltration than untreated controls. Recipients of donor bone marrow also demonstrated early mixed chimerism, which disappeared after 1 month. While allograft survival was prolonged, tolerance was not achieved, and the mechanism of rejection was more consistent with a chronic process. © 2005 Wiley‐Liss, Inc. Microsurgery 25:624–631, 2005.
Gradual graft‐cell repopulation with recipient cells following vasularized bone and limb allotransplantation
Authors: Muramatsu Keiichi , Kurokawa Yoko , Kuriyama Ryutaro , Taguchi Toshihiko , Bishop Allen T.
Published: November 2005

Little is known about the fate of graft cells following vascularized bone allografting. This study was conducted to define the process of graft‐cell repopulation with recipient cells. Sixty‐five vascularized tibial bone and 50 limb allotransplantations were performed in rat sex‐mismatched pairs. FK506 was used for immunosuppression. The ratio of donor and recipient cells in the graft was evaluated by semiquantitative polymerase chain reaction, using the Y‐chromosome primers. Allografted bones had no rejection episodes. In the vascularized bone allograft model, donor‐derived cells were gradually replaced by cells of recipient origin, such that by 24 weeks, they comprised only 10% of total cells. In the limb allograft model, male recipient cells were detected in female grafts not at 1 week but at 48 weeks posttransplantation. The ratio of recipient cells was more than 10% in the femur and tibia. Recipient‐derived cells gradually migrated into the grafted bone cells with the passage of time. © 2005 Wiley‐Liss, Inc. Microsurgery 25:599–605, 2005.
Inhibition of iNOS attenuates skeletal muscle reperfusion injury in extracellular superoxide dismutase knockout mice
Authors: Park Jong Woong , Qi Wen‐Ning , Liu John Q. , Urbaniak James R. , Folz Rodney J. , Chen Long‐En
Published: November 2005

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are closely involved in the mechanism of skeletal muscle ischemia/reperfusion (I/R) injury. This study was designed to determine the effects of inducible nitric oxide synthase (iNOS) inhibitor 1400W on the reperfused cremaster muscle in extracellular superoxide dismutase knockout (EC‐SOD−/−) mice. The muscle was exposed to 4.5 h of ischemia, followed by 90 min of reperfusion. Mice received either 3 mg/kg of 1400W or the same amount of phosphate‐buffered saline (PBS, as a control) subcutaneously at 10 min before the start of reperfusion. 1400W treatment markedly improved the recovery speed of vessel diameter and blood flow in the reperfused cremaster muscle of EC‐SOD−/− mice compared to controls. Histological examination showed reduced edema in the interstitial space and muscle fiber, and reduced density of nitrotyrosine (a marker of total peroxinitrite (ONOO−) level) in 1400W‐treated muscles compared to controls. Our results suggest that iNOS and ONOO− products are involved in skeletal muscle I/R injury. Reduced I/R injury by using selective inhibition of iNOS perhaps works by limiting cytotoxic ONOO− generation, a reaction product of nitric oxide (NO) and superoxide anion (O2−). Thus, inhibition of iNOS appears to be a treatment strategy for reducing clinical I/R injury. © 2005 Wiley‐Liss, Inc. Microsurgery 25:606–613, 2005.
Blow up, decay bounds and continuous dependence inequalities for a class of quasilinear parabolic problems
Authors: Payne L. E. , Philippin G. A. , Vernier‐Piro S.
Published: November 2005

This paper deals with a class of semilinear parabolic problems. In particular, we establish conditions on the data sufficient to guarantee blow up of solution at some finite time, as well as conditions which will insure that the solution exists for all time with exponential decay of the solution and its spatial derivatives. In the case of global existence, we also investigate the continuous dependence of the solution with respect to some data of the problem. Copyright © 2005 John Wiley & Sons, Ltd.
Long‐range JCH heteronuclear coupling constants in cyclopentane derivatives
Authors: Lacerda Valdemar , da Silva Gil V. J. , Constantino Mauricio G. , Tormena Cláudio F. , Williamson R. Thomas , Marquez Brian L.
Published: November 2005

Detailed measurements of long‐range heteronuclear spin–spin coupling constants, especially 2, 3JCH spin–spin couplings for various cyclopentane derivatives, are reported. The measurements are based on a 2D heteronuclear correlation experiment named G‐BIRDR, X‐CPMG‐HSQMBC. Copyright © 2005 John Wiley & Sons, Ltd.
Simultaneous phase correction and SENSE reconstruction for navigated multi‐shot DWI with non‐cartesian k‐space sampling
Authors: Liu Chunlei , Moseley Michael E. , Bammer Roland
Published: November 2005

Phase‐navigated multi‐shot acquisition and parallel imaging are two techniques that have been applied to diffusion‐weighted imaging (DWI) to diminish distortions and to enhance spatial resolution. Specifically, sensitivity encoding (SENSE) has been combined with single‐shot echo planar imaging (EPI). Thus far, it has been difficult to apply parallel imaging methods, like SENSE, to multi‐shot DWI because motion‐induced phase error varies from shot to shot and interferes with sensitivity encoding. Although direct phase subtraction methods have been introduced to correct this phase error, they generally are not suitable for SENSE reconstruction, and they cannot remove all the motion artifacts even if the phase error is fully known. Here, an effective algorithm is proposed to correct the motion‐induced phase error using an iterative reconstruction. In this proposed conjugate‐gradient (CG) algorithm, the phase error is treated as an image encoding function. Given the complex perturbation terms, diffusion‐weighted images can be reconstructed using an augmented sensitivity map. The mathematical formulation and image reconstruction procedures of this algorithm are similar to the SENSE reconstruction. By defining a dynamic composite sensitivity, the CG phase correction method can be conveniently incorporated with SENSE reconstruction for the application of multi‐shot SENSE DWI. Effective phase correction and multi‐shot SENSE DWI (R = 1 to 3) are demonstrated on both simulated and in vivo data acquired with PROPELLER and SNAILS. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
In vivo carbon‐13 magnetization transfer effect. Detection of aspartate aminotransferase reaction
Authors: Shen Jun
Published: November 2005

One of the most remarkable achievements of in vivo NMR spectroscopy has been the detection of rapid enzyme‐catalyzed exchange reactions using phosphorus‐31 magnetic resonance spectroscopy‐based magnetization transfer experiments. In this paper, we report, for the first time, the in vivo carbon magnetization transfer (CMT) effect and in vivo detection of the CMT effects of the α‐ketoglutarate ↔ glutamate and the oxaloacetate ↔ aspartate reactions, both of which are catalyzed by aspartate aminotransferase. By saturating the carbonyl carbon of α‐ketoglutarate at 206 ppm in α‐chloralose anesthetized adult rat brain, the unidirectional glutamate → α‐ketoglutarate flux was determined to be 78 ± 9 μmol/g/min (mean ± SD, n = 11) following i.v. infusion of [1,6‐13C2]D‐glucose. Contribution from aspartate aminotransferase‐catalyzed partial reactions to the observed CMT effects was emphasized. Because of the large chemical shift separation between the α‐carbons of the amino acids and the carbonyl carbons of the corresponding cognate keto acids, the spillover of the saturation radiofrequency pulses to the α‐carbon resonances was negligible. The results indicate that the magnetization transfer effects of aspartate aminotransferase‐catalyzed reactions can be used as new biomarkers accessible to non‐invasive in vivo magnetic resonance spectroscopy techniques. Magn Reson Med, 2005. Published 2005 Wiley‐Liss, Inc.
Quantifying the spatial resolution of the gradient echo and spin echo BOLD response at 3 Tesla
Authors: Parkes Laura M. , Schwarzbach Jens V. , Bouts Annemieke A. , Deckers Roel h R. , Pullens Pim , Kerskens Christian M. , Norris David G.
Published: November 2005

The blood oxygen level dependent (BOLD) response, as measured with fMRI, offers good spatial resolution compared to other non‐invasive neuroimaging methods. The use of a spin echo technique rather than the conventional gradient echo technique may further improve the resolution by refocusing static dephasing effects around the larger vessels, so sensitizing the signal to the microvasculature. In this work the width of the point spread function (PSF) of the BOLD response at a field strength of 3 Tesla is compared for these two approaches. A double echo EPI pulse sequence with simultaneous collection of gradient echo and spin echo signal allows a direct comparison of the techniques. Rotating multiple‐wedge stimuli of different spatial frequencies are used to estimate the width of the BOLD response. Waves of activation are created on the surface of the visual cortex, which begin to overlap as the wedge separation decreases. The modulation of the BOLD response decreases with increasing spatial frequency in a manner dependent on its width. The spin echo response shows a 13% reduction in the width of the PSF, but at a cost of at least 3‐fold reduction in contrast to noise ratio. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Absolute oxygen tension (pO2) in murine fatty and muscle tissue as determined by EPR
Authors: Matsumoto Atsuko , Matsumoto Shingo , Sowers Anastasia L. , Koscielniak Janusz W. , Trigg Nancy J. , Kuppusamy Periannan , Mitchell James B. , Subramanian Sankaran , Krishna Murali C. , Matsumoto Ken‐ichiro
Published: November 2005

The absolute partial pressure of oxygen (pO2) in the mammary gland pad and femoral muscle of female mice was measured using EPR oximetry at 700 MHz. A small quantity of lithium phthalocyanine (LiPc) crystals was implanted in both mammary and femoral muscle tissue of female C3H mice. Subsequent EPR measurements were carried out 1–30 days after implantation with or without control of core body temperature. The pO2 values in the tissue became stable 2 weeks after implantation of LiPc crystals. The pO2 level was found to be higher in the femoral muscle than in the mammary tissue. However, the pO2 values showed a strong dependence on the core body temperature of the mice. The pO2 values were responsive to carbogen (95% O2, 5% CO2) breathing even 44–58 days after the implantation of LiPc. The LiPc linewidth was also sensitive to changes in the blood supply even 60 days after implantation of the crystals. This study further validates the use of LiPc crystals and EPR oximetry for long‐term non‐invasive assessment of pO2 levels in tissues, underscores the importance of maintaining normal body core temperature during the measurements, and demonstrates that mammary tissue functions at a lower pO2 level than muscle in female C3H mice. Magn Reson Med, 2005. Published 2005 Wiley‐Liss, Inc.
Monitoring T‐lymphocyte trafficking in tumors undergoing immune rejection
Authors: Hu De‐En , Kettunen Mikko I. , Brindle Kevin M.
Published: November 2005

Activated T cells, isolated from animals that had rejected a tumor (E.G7‐OVA) expressing chicken ovalbumin, were labeled with citrated superparamagnetic iron oxide nanoparticles at an intracellular iron concentration of up to 0.5 pg/cell. Injection of these labeled T cells into animals bearing E.G7‐OVA tumors undergoing immune rejection resulted in tumor infiltration of these cells, which was detectable as a heterogeneous decrease in intensity in T2‐weighted MR images. T‐cell infiltration was confirmed by immunohistochemical staining of tumor sections obtained postmortem and was shown to colocalize with iron that had been stained using Prussian blue. Tumor rejection was correlated with the uptake of labeled T cells, since the infiltration of labeled T cells was only observed in those tumors that went on to regress. This technique should assist in the elucidation of those factors that are important in mediating tumor immune rejection. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Effect of strong homonuclear proton coupling on localized 13C detection using PRESS
Authors: Yahya and Atiyah , Allen Peter S.
Published: November 2005

The effect of strong homonuclear proton coupling on 13C incorporation measurements by either indirect or direct means was investigated (and illustrated with glutamate) both numerically and experimentally at 3.0 T. In particular, two sequences were considered, each using a proton PRESS sequence for localization. The indirect 13C detection method incorporated the POCE (proton observe carbon edited) technique onto PRESS, and for direct 13C detection a DEPT (distortionless enhancement by polarization transfer) sequence was appended to the PRESS localization. Both analysis and experiment demonstrate that when strong homonuclear coupling of protons is additional to heteronuclear coupling with 13C spins, the 13C measures derived from either the indirect PRESS‐POCE sequence or the direct‐but‐enhanced PRESS‐DEPT sequence are significantly modified. Specifically, the MR lineshapes of both 13C‐bonded and nonbonded protons are changed during 13C incorporation, giving rise, for example, to a potential cross‐contamination of ≤30% between glutamate 13C3 and 13C4 measures from the PRESS‐POCE indirect method. During direct‐but‐enhanced detection, the DEPT enhancement is reduced for glutamate 13C2, 13C3, and 13C4 but not equally, and the reduction is further exacerbated by proton PRESS localization, which gives rise to enhancements that are strong functions of PRESS TE1 and TE2. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Combination of optimized transmit arrays and some receive array reconstruction methods can yield homogeneous images at very high frequencies
Authors: Collins Christopher M. , Liu Wanzhan , Swift Bryan J. , Smith Michael B.
Published: November 2005

Image inhomogeneity related to high radiofrequencies is one of the major challenges for high field imaging. This inhomogeneity can be thought of as having 2 radiofrequency‐field related contributors: the transmit field distribution and the reception field distribution. Adjusting magnitude and phase of currents in elements of a transmit array can significantly improve flip angle homogeneity at high field. Effective application of some well‐known parallel imaging and other receive array post‐processing methods removes receptivity patterns from the intensity distribution in the final image, though noise then becomes a function of position in the final image. Here simulations are used to show that, assuming high signal‐to‐noise ratio, very homogeneous images in the human head can be acquired with the combination of transmit arrays and some receive array reconstruction methods at frequencies as high as 600 MHz. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.
Fully automated shim mapping method for spectroscopic imaging of the mouse brain at 9.4 T
Authors: Miyasaka Naoyuki , Takahashi Kan , Hetherington Hoby P.
Published: November 2005

For spectroscopic imaging studies of the mouse brain, it is critical to obtain optimal B0 homogeneity over a large region of interest (ROI). In this paper, a fully automated shimming method for mouse brain at 9.4 T, based on B0 mapping, is described. B0 maps were obtained using a multislice gradient echo sequence with multiple phase evolution time delays with a novel unwrapping scheme. The unwrapping method allows phase maps with large bandwidths (±1 kHz) but with high resolution (0.3 Hz/°) to be acquired in a single acquisition, thereby minimizing the number of iterations required. The SD of the B0 over the ROI (8 × 5 × 1 mm) was less than 10 Hz after shimming. Application of this method to the in vivo mouse brain allowed reproducible, high‐quality spectroscopic data to be collected with 1‐μl voxels. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.