bluuebunny/crossref_metadata_2025 huggingface dataset:
Time Scales in Polymer Modified Asphalts
Authors: Polacco Giovanni , Stastna Jiri , Biondi Dario , Vlachovicova Zora , Zanzotto Ludovit , Magagnini Pierluigi
Published: September 2005

Historically, Maxwell was probably the first one who recognized the importance of time scales for understanding the mechanical response of asphalt. In instantaneous response asphalt behaves as an elastic, solid‐like material, on the other hand its long time response is that of a viscous, fluid‐like material. In the linear viscoelastic region asphalt behaves as a low molecular weight polymer. However, in the nonlinear region of high strains or rates of strain the behavior of some asphaltic systems can be rather complicated. In asphalts, asphaltenes, resins and alkanes compose a complex colloidal system, in which alkanes act as a solvent, asphaltenes as micelles and the polar resins as stabilizers. In order to enhance the mechanical properties of asphalts they are frequently modified by blending them with appropriate polymers. Changes in the impermanent network that can be formed in some of these blends can lead to an unexpected behavior of the steady shear viscosity function. Several different time scales emerge from this behavior. A possible relation of these “nonlinear” time scales to the linear viscoelastic time scales is discussed and examples of anomalous behavior of polymer‐modified asphalts are given.
Dielectric and Viscoelastic Study of Entanglement Dynamics: A Review of Recent Findings
Authors: Watanabe Hiroshi , Matsumiya Yumi , Inoue Tadashi
Published: September 2005

This article gives a review of the results of recent dielectric and viscoelastic studies for entangled binary blends of linear cis‐polyisoprenes to explain the current understanding of the equilibrium entanglement dynamics on the basis of the molecular picture of dynamic tube dilation (DTD). Comparison of dielectric and viscoelastic properties reveals that the full‐DTD picture regarding the relaxed portions of the chains as a solvent fails for the high molecular weight component chain in the blends at intermediate times. This failure is related to insufficient constraint release (CR) equilibration of the entanglement segments of this chain. A partial‐DTD picture properly considering this CR equilibration successfully describes the linear relaxation behavior of the blends. The dielectric and viscoelastic properties of PI under fast flow, being affected by the flow‐activated CR/DTD mechanism, are also presented in order to demonstrate the usefulness of the comparison of these properties in both equilibrium and non‐equilibrium states.
Rheology of a Semi‐Rigid Thermotropic Liquid Crystalline Polymer
Authors: Somma E. , Nobile M.R.
Published: September 2005

In this work the rheological behaviour of different Mw samples of a thermotropic liquid crystalline polymer (TLCP), the random copolymer HBA/HNA 73/27 produced by Ticona, has been investigated. The linear viscoelastic behavior has been discussed. The G′ (shear storage modulus) and G″ (shear loss modulus) have been monitored as a function of frequency and of different annealing times. Rheological data obtained in steady state conditions have been used to define the viscosity flow curves for the different MW samples. In all the cases a three regions flow curve has been detected, with the plateau zone being Mw dependent.
Fullerene‐Like Structures as Interaction Sites between Carbon Black and Rubber
Authors: Cataldo Franco
Published: September 2005

Ball‐milling of N660 carbon black and graphite causes a deep activation of its surface activity which can be measured by a significant increase in the bound rubber level and in the amount of grafted rubber in comparison to the pristine untreated samples.

The bound rubber measurement has been done also on a natural rubber masterbatch filled with extracted fullerene carbon black (EFCB). Also in this case extremely high levels of rubber grafting have been achieved in comparison to pure untreated graphite. It is discussed and demonstrated that the fullerene‐like nanostructures in carbon blacks play a key role in the formation of bound rubber phenomenon and in grafting natural rubber on carbon black surface.
Effect of Clay/Diamond and Clay/Carbon Nanosystems on Structure‐Properties Relationships of iPP
Authors: Silvestre Clara , Cimmino Sossio , Raimo Maria , Carfagna Cosimo , Capuano Vincenzo , Kotsilkova Rumiana
Published: September 2005

The effect of the addition of two combined fillers, smectite clay and diamond and smectite clay and carbon nanoparticles, on structure, morphology, isothermal and non isothermal crystallization behaviour, tensile and thermal properties of isotactic polypropylene (iPP) has been investigated by using several techniques: wide angle X‐ray diffraction, optical and scanning electron microscopy, thermogravimetry, differential scanning calorimetry and tensile techniques. It was found that nanoparticles of diamond and carbon favour the nucleation of the β‐form of iPP crystal, whereas the clay nanolayers do not have any influence on the crystal structure of iPP. The thermal stability of iPP/(clay+diamond) and iPP/(clay+carbon) is improved with respect to neat iPP, whereas no influence is detected when only clay is added to iPP. At the given crystallization conditions, the overall crystallization peak of iPP/(clay+diamond) almost exactly overlaps the crystallization peak of neat iPP, whereas in the case of iPP/clay and iPP/(clay+carbon) the maximum of the crystallization peaks is shifted to higher temperature. The spherulite growth rate, G values do not differ from one another. The iPP/(clay+carbon) system shows ductile behavior. The other systems show brittle behavior with failure before necking. These results were related with the very high percentage of beta phase present in the samples of iPP/(clay+carbon).
Barrier and Mechanical Properties of Poly(caprolactone)/organoclay Nanocomposites
Authors: Di Yingwei , Iannac Salvatore , Sanguigno Luigi , Nicolais Luigi
Published: September 2005

In this study, biodegradable poly(caprolactone) (PCL) hybrids with two types of organoclays: Cloisite 30B (30B) and Cloisite 93A (93A) have been prepared by melt mixing and their barrier performance to air permeation and mechanical properties were investigated. The hybrids of PCL/30B were found to be nanocomposites resulted from the strong interaction between organic modifier of 30B and PCL and those of PCL/93A were microcomposites. The barrier performance of PCL/30B nanocomposite film to air permeation was much more improved than pure PCL and PCL/93A microcomposites at low organoclay concentration. With the increase of organoclay content the permeability coefficient was also increased that could attributed to the extra tortuous pathway for gas permeation caused by organoclay exfoliation. The barrier behaviour of PCL/30B nanocomposites could be approximately described by a theoretical model developed for composites. The mechanical properties measurements showed that the reinforcement of organoclay 30B in nanocomposites is more significant than 93A in microcomposites. Both tensile modulus and tensile strength were increased in PCL/30B nanocomposites even at at low amount of organoclay without much loss of strain at break as compared to pure PCL. The significant improvements in both barrier and mechanical properties in PCL nanocomposites could be attributed to the fine dispersion state of organoclay 30B platelets in PCL matrix and the strong interaction between organic modifier of 30B and matrix molecules.
Thin Silicon Films on Polymeric Substrate
Authors: Imparato Antonio , Minarini Carla , Rubino Alfredo , Tassini Paolo , Villani Fulvia , Guerra Alfredo , Amendola Eugenio , Della Sala Dario
Published: September 2005

Laser crystallization of amorphous silicon film on polymeric substrate is reported. Intrinsic amorphous films 1000 Å thick have been deposited on Polyethersulphone (PES) by PECVD technique in the deposition temperature range of 120‐200 °C. Dehydrogenation and crystallization of the thin films have been obtained by high energy (10 J) XeCl pulsed excimer laser. The irradiation conditions have been varied to study their influence on dehydrogenated and crystallized material properties. Electrical and optical properties of as‐deposited and crystallized films have been investigated. Structural characterization (SEM, XRD, AFM) has been performed. Average crystallite size and grain distribution have been evaluated.

For the substrate, the glass transition temperature (Tg) and the coefficient of thermal expansion (CTE) have been evaluated by DSC (Differential Scanning Calorimetry) and TMA (Thermo Mechanical Analysis) measurements and the compatibility with the deposition and crystallization processes have been verified.
Polyurethane Films for Wound Dressing Applications
Authors: Ozkaynak Mert Umut , Atalay‐Oral Cigdem , Tantekin‐Ersolmaz S. Birgül , Güner F. Seniha
Published: September 2005

Polyurethane films based on renewable sources were prepared as an alternative to petroleum‐based polyurethane. The effects of the structure and ratio of diisocyanate components on polymer properties were investigated. Hexamethylene diisocyanate (HMDI) and diphenylmethylene diisocyanate (MDI) were chosen as the diisocyanate components in polymer synthesis. Membranes were prepared by casting‐evaporation technique and characterized for their gas permeability, film and mechanical properties. The oil‐based membranes were found to be suitable for wound dressing applications.
Chain Extension and Foaming of Recycled PET in Extrusion Equipment
Authors: Di Maio L. , Coccorullo I. , Montesano S. , Incarnato L.
Published: September 2005

In this work industrial scraps of poly(ethylene terephthalate) (PET) were used for the production of foamed sheets. The process was performed by making use of a chemical blowing agent (CBA) in the extrusion process. Due to the low intrinsic viscosity of the recycled PET (IV=0.48dl/g), a chain extender was also used in order to increase the molecular weight of the polymer matrix. Pyromellitic dianhydride (PMDA) and Hydrocerol CT 534 were chosen as chain extender and CBA, respectively. The reactive extrusion and foaming were performed in a two step process, analyzing the feasibility regarding an eventual use in an industrial context. Rheological characterization was carried out on PET samples previously treated with PMDA, as well as the morphological study was performed to define the cellular structure of the foams produced. Moreover, in order to correlate the working conditions in the reactive and the foaming processes with the final morphology of the foams, a mathematical modelling of the foaming process was applied.
Effect of Molecular Modification on PCL Foam Formation and Morphology of PCL
Authors: Di Maio E. , Iannace S. , Marrazzo C. , Narkis M. , Nicolais L.
Published: September 2005

Poly(ϵ‐caprolactone) was chemically modified by using dicumyl peroxide from 0.25 to 2 % (w/w) and the effects of molecular architecture on the density and morphology of PCL foams were examined. The polymer was first blended with dicumyl peroxide at a low temperature (80°C), to prevent premature peroxide decomposition. The peroxide modification was then performed at different temperatures, from 110°C to 150°C. The reaction kinetic was followed by measuring the dynamical rheological properties of the melt in isothermal experiments by using a parallel plate rheometer. The evolution of the macromolecular structure during the chemical reaction was followed by analyzing the time evolution of the complex viscosity. Foams were prepared from the peroxide modified PCL with a batch foaming process using nitrogen as the foaming agent under different process conditions. As expected, the increase of the molecular modification led to a shift towards higher temperatures of the foaming window and, moreover, influenced the viscoelastic behavior of the expanding polymeric matrix so that the final foam properties are affected.
Production of Viscosity Improvers for PVC
Authors: Bostanci Taner , Güner F. Seniha , Erciyes Tuncer
Published: September 2005

Some oil‐based samples having oxygen, ester, amide, acid and/or hydroxyl structure were prepared for using as lubricants in PVC extrusion. After characterization studies, all samples were tested in PVC formulation using Brabender W50 EHT Lab‐Station mixer and extruder. The results were compared with that of a commercial product. From the mixer results, it can be noted that energy consumption was lowered for samples containing acid and amide structures. Surface roughness and opacity of the products were improved when the extruder screw speed was increased from 20 rpm to 60 rpm.
In situ Polymerisation of Urethane‐Urea Copolymers for Tuff Consolidation
Authors: Cocca M. , D'Arienzo L. , D'Orazio L. , Gentile G. , Martuscelli E.
Published: September 2005

Two different diisocyanates were investigated as co‐monomers for in situ polymerisation of poly(urethane‐urea) into Neapolitan yellow tuff for conservation and restoration purpose. The obtained copolymers were characterised by means of FTIR spectroscopy, whereas the protective and consolidating efficiency of the performed treatments was evaluated through water capillary absorption, water vapour permeability and abrasion resistance measurements. The distribution and the penetration depth of the synthesized copolymer were also analysed applying micro‐FTIR. The morphology of treated tuff was investigated by SEM. It was shown that comparatively higher protective and consolidating properties are achieved by using 1,6‐diisocyanatohexane as monomer for in situ polymerisation.
Diffusion of Organic Vapors in Materials for Gas Sensing Application
Authors: Penco Maurizio , Sartore Luciana , Della Sciucca Stefania , D'Amore Alberto
Published: September 2005

Mass‐variation measurements were carried out on carbon black (CB)‐poly(vinyl chloride) (PVC) composite film with 40% by weight of di(2‐ethylhexyl)‐phthalate (DOP), cast on resonant piezo‐layer (RPL) elements of lead zirconat titanate (PZT). Even if anomalous diffusion is predicted by fitting the data with Mt/M∞=ktα, the fractional uptake Mt/M∞ is linear with the square root of the time up to Mt/M∞=0.6, suggesting Fickian behavour. The anomalous values of α are probably due to experimental time lag. A dependence of the diffusion on the morphology of the material and the penetrant shape and flexibility has been found.
Analysis of Composites with Infrared Thermography
Authors: Meola Carosena , Carlomagno Giovanni Maria , Squillace Antonino , Prisco Umberto , Morace Renata Erica
Published: September 2005

The aim of this study was a non‐destructive evaluation of composites through their behaviour under thermal stimulation. Such behaviour was monitored by infrared thermography. Several specimens were fabricated involving: glass/epoxy with inclusion of foreign materials; carbon/epoxy with backdrilled holes; carbon/epoxy with impact damage; Glare® failed in bearing way. The obtained results prove that infrared thermography is capable of detecting the materials inhomogeneities and/or damage listed above. In particular, lock‐in thermography is capable of supplying useful information about: the distribution of the adhesive thickness in composite structures; the distribution of the paint thickness; the behaviour under load of aluminium layers and glass fibres in Glare®.
Achievements and Research Tasks for Poly(vinyl chloride) Ageing and Stabilization
Authors: Minsker K.S. , Zaikov G.E. , Zaikov V.G.
Published: September 2005

Perspectives of PVC manufacture, not containing of labile groups in a backbone are considered. It will provide drastic increase of an intrinsic stability of polymeric products, possibility of PVC processing with the minimal contents or in total absence of stabilizers and other chemicals ‐ additives and opportunity of creation of materials and products on a PVC basis with the essentially increased service life‐time. Presented data allow to create rigid, semi‐rigid and flexible (plasticized) materials and products with the minimal contents of chemicals ‐ additives and increased life‐time of their service at exploitation in natural and special conditions.
Benzodiazepine analogues. Part 21. 13C NMR analysis of benzoxathiepine derivatives
Authors: Gelebe Aifheli C. , Kaye Perry T. , Klein Rosalyn , Sewry Joyce D. , Soper Andrew G.
Published: September 2005

The influence of substituents and structure on the 13C NMR spectra of four series of benzoxathiepine derivatives has been investigated. Signal assignments in the 13C NMR spectra have been facilitated by the use of several predictive methods, permitting comparison of their relative efficacy. Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis and characterization of novel biodegradable block copolymer poly(ethylene glycol)‐block‐poly(L‐lactide‐co‐2‐methyl‐2‐carboxyl‐propylene carbonate)
Authors: Guan Hui‐Li , Xie Zhi‐Gang , Zhang Pei‐Biao , Wang Xin , Chen Xue‐Si , Wang Xian‐Hong , Jing Xia‐Bin
Published: September 2005

An amphiphilic block copolymer, poly(ethylene glycol)‐block‐poly(L‐lactide‐co‐2‐methyl‐2‐benzoxycarbonyl‐propylene carbonate) [PEG‐b‐P(LA‐co‐MBC)], was synthesized in bulk by the ring‐opening polymerization of L‐lactide with 2‐methyl‐2‐benzoxycarbonyl‐propylene carbonate (MBC) in the presence of poly(ethylene glycol) as a macroinitiator with diethyl zinc as a catalyst. The subsequent catalytic hydrogenation of PEG‐b‐P(LA‐co‐MBC) with palladium hydroxide on activated charcoal (20%) as a catalyst was carried out to obtain the corresponding linear copolymer poly(ethyleneglycol)‐block‐poly(L‐lactide‐co‐2‐methyl‐2‐carboxyl‐propylenecarbonate) [PEG‐b‐P(LA‐co‐MCC)] with pendant carboxyl groups. DSC analysis indicated that the glass‐transition temperature (Tg) of PEG‐b‐P(LA‐co‐MBC) decreased with increasing MBC content in the copolymer, and Tg of PEG‐b‐P(LA‐co‐MCC) was higher than that of the corresponding PEG‐b‐P(LA‐co‐MBC). The in vitro degradation rate of PEG‐b‐P(LA‐co‐MCC) in the presence of proteinase K was faster than that of PEG‐b‐P(LA‐co‐MBC), and the cytotoxicity of PEG‐b‐P(LA‐co‐MCC) to chondrocytes from human fetal arthrosis was lower than that of poly(L‐lactide). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4771–4780, 2005
Cyclic poly(pyridine ether)s by the polycondensation of 2,6‐difluoropyridine with various diphenols
Authors: Kricheldorf Hans R. , Garaleh Mazen , Schwarz Gert
Published: September 2005

The bistrimethylsilyl derivatives of six different diphenols were polycondensed with 2,6‐difluoropyridine in N‐methylpyrrolidone in the presence of K2CO3. On the basis of previous studies, the reaction conditions were optimized for almost quantitative conversions. The feed ratio was systematically varied to optimize the molecular weight. A 2 mol % excess of 2,6‐difluoropyridine was needed to obtain maximum molecular weights. In the matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectra of the optimized polyethers, only cycles were found (detectable up to 5000 Da). Obviously, the relatively low molecular weights obtained under optimized conditions resulted from a limitation of the chain growth by cyclization, indicating a high cyclization tendency for poly(pyridine ether)s. The size exclusion chromatography measurements not only proved low molecular weights but also demonstrated the existence of bimodal mass distributions and high polydispersities. Protonation of the poly(pyridine ether)s required strong acids such as methane or trifluoromethane sulfonic acid. The solubilities of the neutral and protonated polyethers derived from bisphenol A were studied in various solvents. The MALDI‐TOF mass spectra proved that protonation at 20–25 °C did not cause cleavage of ether bonds. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4781–4789, 2005
Influence of the chemical structure of dithiocarbamates with different N‐groups on the reversible addition–fragmentation chain transfer polymerization of styrene
Authors: Zhou Di , Zhu Xiulin , Zhu Jian , Yin Haishu
Published: September 2005

Polymerizations of styrene with azobisisobutyronitrile initiation or thermal initiation have been performed in the presence of dithiocarbamates with different N‐groups, that is, benzyl 4,5‐diphenyl‐1H‐imidazole‐1‐carbodithioate (2a), benzyl 1H‐1,2,4‐triazole‐1‐carbodithioate (2b), benzyl indole‐1‐carbodithioate (2c), benzyl 2‐phenyl‐indole‐1‐carbodithioate (2d), benzyl phenothiazine‐10‐carbodithioate (2e), benzyl 9H‐carbazole‐9‐carbodithioate (2f), and benzyl dibenzo[b,f]azepine‐5‐carbodithioate (2g). The results show that the structure of the N‐group of dithiocarbamates has significant effects on the activity of dithiocarbamates for the polymerization of styrene. 2a, 2b, 2c, 2d, and 2f are effective reversible addition–fragmentation chain transfer (RAFT) agents for the RAFT polymerization of styrene, and the polymerizations have good living characteristics. However, in the cases of 2e and 2g, the obtained polymers have uncontrolled molecular weights and broad molecular weight distributions. The polymerization rate is markedly influenced by the conjugation structure of the N‐group of the dithiocarbamate, and the polymerization rate of 2b is greater than that of 2a. For 2b, the rate of polymerization seems independent of the RAFT agent concentration. However, a significant retardation in the rate of polymerization can be observed in the case of 2c. 2d is more effective than 2c, and the substitution group of phenyl on this dithiocarbamate has obvious effects on the effectiveness of the controlled polymerization of styrene. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4849–4856, 2005
Synthesis of triblock copolymers based on two isomer acrylate monomers by atom transfer radical polymerization
Authors: Muñoz‐Bonilla Alexandra , Cerrada María L. , Fernández‐García Marta
Published: September 2005

The syntheses of triblock copolymers by the atom transfer radical polymerization of tert‐butyl and iso‐butyl acrylates as inner blocks with cyclohexyl methacrylate as outer blocks are reported. The living behavior and blocking efficiency of these polymerizations were investigated in each case. The use of difunctional macroinitiators led to ABA triblock copolymers with narrow polydispersities and controlled number‐average molecular weights. These copolymers were prepared from bromo‐terminated macroinitiators of poly(tert‐butyl acrylate) and poly(iso‐butyl acrylate), with copper chloride/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as the catalytic system, at 40 °C in 50% (v/v) toluene solutions. The block copolymers were characterized with size exclusion chromatography and 1H NMR spectroscopy. Differential scanning calorimetry measurements were performed to reveal the phase segregation. The glass transition of the inner block was not clearly detected, with the exception of the copolymer synthesized with the longest poly(iso‐butyl acrylate) macroinitiator length. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4828–4837, 2005
Radical‐mediated modification of polypropylene: Selective grafting via polyallyl coagents
Authors: Sengupta Saurav S. , Parent J. Scott , McLean J. Keith
Published: September 2005

Selective graft modifications of polypropylene (PP) are demonstrated in which desirable functionality is introduced without the degradation that accompanies conventional radical‐mediated processes. A range of modification strategies is presented, each exploiting triallyl trimellitate (TATM) or its derivatives to counteract the effects of macroradical fragmentation on the molecular weight. Model compound studies, as well as examinations of atactic PP reaction products, show that allylic ester activation occurs predominately by a radical‐addition/hydrogen‐transfer sequence, with a limited propensity for telomerization. The cografting of TATM and maleic anhydride leads to maleated PP of a high melt viscosity, whereas the apparent incompatibility of TATM with vinyltrimethoxysilane requires the use of TATM‐assisted thiol–ene addition and/or diallyl silane grafting to produce moisture‐curable PP derivatives. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4882–4893, 2005
Synthesis and characterization of biodegradable triblock copolymers based on bacterial poly[(R)‐3‐hydroxybutyrate] by atom transfer radical polymerization
Authors: Zhang Xueqin , Yang Hu , Liu Quanwei , Zheng Yun , Xie Hongfeng , Wang Zhiliu , Cheng Rongshi
Published: September 2005

Biodegradable poly(tert‐butyl acrylate)–poly[(R)‐3‐hydroxybutyrate]–poly (tert‐butyl acrylate) triblock copolymers based on bacterial poly[(R)‐3‐hydroxybutyrate] (PHB) were synthesized by atom transfer radical polymerization. The chain architectures of the triblock copolymers were confirmed by 1H NMR and 13C NMR spectra. Gel permeation chromatography analysis was used to estimate the molecular weight characteristics and lengths of the PHB and poly(tert‐butyl acrylate) blocks of the copolymers. The thermal properties of the copolymers were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA showed that the triblock copolymers underwent stepwise thermal degradation and had better thermal stability than their respective homopolymers, whereas DSC analyses showed that a microphase‐separation structure was formed only in the triblock copolymers with the longer PHB block. As a similar result, from wide‐angle X‐ray diffraction experimentation, the crystalline phase of PHB could not be seen evidently in the triblock copolymers with the shorter PHB block. The enzymatic hydrolysis of the copolymer films was carried at 37 °C and pH 7.4 in a potassium phosphate buffer with an extracellular PHB depolymerase from Penicillum sp. The biodegradability of the triblock copolymers increased with an increase in the PHB block content. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4857–4869, 2005
Using scanning electron, confocal and optical microscopes to measure microscopic holes in trays
Authors: Bix Laura , Kassarjian Ondrea , Cardoso Fernando , Lockhart Hugh
Published: September 2005

Package integrity is of paramount importance to the medical device industry. As healthcare costs soar and integrity testers become more and more sensitive, concern with the question ‘what hole size allows microbial penetration into device packages?’ is re‐ignited. However, producing a consistent and measurable defect in the microcosm presents challenges. Varying techniques are currently employed to produce these defects. Use of an excimer laser is one of the most precise and accurate techniques, and holes ‘certified’ to be a given size can be purchased at a significant cost. To verify the accuracy and precision of holes drilled with an excimer laser, researchers measured laser‐drilled ‘exit’ and ‘entry’ holes in glycol‐modified polyetheylene terephthalate (PETG) trays using scanning electron microscopy (SEM) and confocal microscopy. This data and the certification data provided by the laser driller were analysed using a mixed‐model analysis of variance (ANOVA). Both the effect of measuring technique and hole side (entry vs. exit) were found to be significant. These significant differences have the potential to impact the question that the industry faces with regard to penetration threshold. This suggests that a shift in thinking is needed. Perhaps it would be better if the industry stops thinking about hole size and begins to think in terms of what researchers have referred to as the ‘effective hole’, which is defined as the volume of gas that will flow through a hole of defined size per unit time. Copyright © 2005 John Wiley & Sons, Ltd.
Response surface optimization of the feed compositions of biodegradable packaging foams
Authors: Peng Jinchyau , Wei Kaishuen , Lui Wai‐Bun
Published: September 2005

Response surface methodology (RSM) was used to analyse the effects of polyvinyl alcohol (PVOH) and calcium carbonate (CaCO3) on the physical and mechanical properties (radial expansion ratio, bulk density, compressibility and spring index) of a biodegradable cushioning extrudate. A rotatable central‐composite design (CCD) was used to develop models for the objective responses. The experiments were run at 125°C with a feed rate of 27.8 l/h, screw speed of 215 r.p.m. and die diameter of 3.92 mm. Responses were most affected by changes in PVOH levels and to a lesser extent by CaCO3 levels. Individual contour plots of the different responses were overlaid. An optimum radial expansion ratio of 3.39, bulk density of 0.065 (g/cm3), compressibility of 32.27(N), and spring index of 0.906 were identified at 36% PVOH and 5% CaCO3. Copyright © 2005 John Wiley & Sons, Ltd.
Quantum dynamics in high‐spin molecules, spin dendrimers, and spin lattices
Authors: Takahata Masahiro , Shoji Mitsuo , Nitta Hiroya , Takeda Ryo , Yamanaka Shusuke , Okumura Mitsutaka , Nakano Masayoshi , Yamaguchi Kizashi
Published: September 2005

We perform spin dynamics in strongly correlated electron–spin systems to clarify the relationship between the phase relaxation and the structure of the spin systems. The interaction among spins is considered to be Heisenberg‐type exchange. The quantum Liouville approach is used for the dynamics involving the relaxation processes of the systems, which is considered to originate in spin–phonon and electron spin–nuclear spin interactions. As a first step of our study, to examine the effects of the structures on the phase relaxation, we consider the phenomenological relaxation parameters for the relaxation terms of quantum Liouville equation, and perform the spin dynamics in four types of four electron–spin systems that have linear, square, star (dendritic structure), and tetrahedral structures. The results of our calculation indicated the possibility for the control of the phase relaxation by the change of the structure in spin clusters. Possible implications of our results are related to the single‐molecule magnets, ESR‐STM detection of spins, and related spin‐transition phenomena (decoherence and population relaxation). © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Highly sensitive high‐performance liquid chromatography/selective reaction monitoring mass spectrometry method for the determination of cyclophosphamide and ifosfamide in urine of health care workers exposed to antineoplastic agents
Authors: Sottani Cristina , Tranfo Giovanna , Faranda Paolo , Minoia Claudio
Published: September 2005

In recent years, the potential for exposure of health care workers to antineoplastic agents has led to the establishment of more restrictive government and professional standards and procedures for handling cytotoxic drugs. Therefore, the detection of low exposure levels is a new and important aim of biological monitoring. In the present paper we report an assay for the simultaneous determination of cyclophosphamide (CP) and ifosfamide (IF) in urine, using electrospray ionization liquid chromatography/tandem mass spectrometry with selective reaction monitoring (HPLC/SRM‐MS). A rapid sample preparation procedure uses a solid‐phase extraction stage with C18 columns. The urine assay is linear over the range 0.02 to 0.4 µg/L, with lower limits of quantification (LLOQs) of 0.02 and 0.04 µg/L for CP and IF. The accuracy and precision have been carried out through the validation study. The intra‐day precision, expressed as relative standard deviation (RSD), is found to be always less than 14.7% for both analytes. The overall precision, assessed on three different days, is less than 15.0%. The recovery of ozaxaphosphorines ranges from 83.5% (CP) to 88.5% (IF) with a RSD always less than 14.6%. The uncertainty of the overall method was also evaluated, to identify possible sources of error. The combined uncertainty was less than 25% over all the days of the validation study. This method is selective and sensitive enough to determine trace levels of CP and IF in a range of urine concentrations relevant to performing low exposure assessment. Copyright © 2005 John Wiley & Sons, Ltd.
Complementary use of Fourier transform laser microprobe mass spectrometry and time‐of‐flight static secondary ion mass spectrometry for the study of the surface adsorption of organic dyes on silicate materials
Authors: Busuioc Alina‐Maria , Mondt Roel De , Moisio Harri , Cool Pegie , Vasile Aurelia , Bilba Nicolae , Vansant Etienne , Vaeck Luc Van
Published: September 2005

The adsorption of organic ionic dyes on different pore size engineered silica materials with potential application for industrial wastewater treatment has been investigated using Fourier transform laser microprobe mass spectrometry (FT‐LMMS) and time‐of‐flight secondary ion mass spectrometry (TOF‐S‐SIMS). The complementary use of the two methods with different information depth allowed data on the subsurface distribution and pore penetration of the adsorbed organic compounds. Macroscopic methods were employed to determine the amount adsorbed on the particles and the specific external surface area. Local MS analysis allows identification of the organic dyes exclusively at the outer particle surface when the pore size is inferior to the size of the adsorbing molecule, or at the surface of the channels inside the material. Specifically, the monolayer information depth of TOF‐S‐SIMS causes a signal to refer essentially to the adsorbate at the outer particle surface, which is only a fraction of the total adsorption in mesoporous materials, while FT‐LMMS allowed detection of the presence of adsorbates at the outer surface as well as inside the subsurface of 10 to 50 nm depending on the material under study. The observed data open perspectives for the molecular monitoring of the adsorption behaviour of different materials at the (sub) µm scale. Copyright © 2005 John Wiley & Sons, Ltd.
Multi‐residue liquid chromatography/tandem mass spectrometric analysis of beta‐agonists in urine using molecular imprinted polymers
Authors: Van Hoof Nathalie , Courtheyn Dirk , Antignac Jean‐Philippe , Van de Wiele Mieke , Poelmans Sofie , Noppe Herlinde , De Brabander Hubert
Published: September 2005

Ion suppression, a matrix effect that affects quantitative mass spectrometry, is one of the main problems encountered in liquid chromatography/tandem mass spectrometry. Two different clean‐up steps for the multi‐residue analysis of beta‐agonists in urine were evaluated with respect to minimisation of ion suppression, namely, a mixed‐phase solid phase extraction (SPE) column, i.e., clean screen Dau (CSD), and a molecular imprinted polymer (MIP) SPE column. Ion suppression experiments revealed that CSD sample clean‐up can lead to false negative results for some beta‐agonists, and that clean‐up using MIP columns is more selective for beta‐agonists than the use of CSD columns. Copyright © 2005 John Wiley & Sons, Ltd.
Refinements to the diastereoisomer‐specific method for the analysis of hexabromocyclododecane
Authors: Tomy Gregg T. , Halldorson Thor , Danell Robert , Law Kerri , Arsenault Gilles , Alaee Mehran , MacInnis Gordia , Marvin Chris H.
Published: September 2005

The emergence of hexabromocyclododecane (HBCD) as a bromine‐based flame retardant of concern is partly attributable to recent measurements on the environmental occurrence of the individual diastereoisomers (α, β and γ). These measurements were fuelled by a newly developed liquid chromatography/tandem mass spectrometric (LC/MS/MS)‐based analytical method. However, in the course of our recent studies on the environmental fate and behaviour of the diastereoisomers of HBCD, some interesting features of the LC/MS/MS method became apparent. For example, the ion signal of the native ions was found to be dependent on the final extract volume. This was true for both biotic and sediment samples and was found to arise from the suppression of the ion signal due to endogenous material in the extracts that escape clean‐up. We have also found differences in the stability of the diastereoisomers in different solvents. If left unaccounted for, both factors can compromise analytical measurement data. By way of a series of controlled experiments conducted at our two laboratories [Department of Fisheries & Oceans Canada (DFO) and Environment Canada (EC)], we illustrate these features and demonstrate that use of newly synthesized labelled HBCD isomers [(13‐carbon (13C) and deuterium (d18)] can minimize and often circumvent matrix‐related effects. Copyright © 2005 John Wiley & Sons, Ltd.
On‐line pretreatment using methylcellulose‐immobilized cation‐exchange restricted access media for direct liquid chromatography/mass spectrometric determination of basic drugs in plasma
Authors: Kawano Shin‐ichi , Takahashi Masatoshi , Hine Takashi , Yamamoto Eiichi , Asakawa Naoki
Published: September 2005

A novel methylcellulose‐immobilized restricted access media column with strong cation‐exchange groups on an internal surface (MC‐SCX) was evaluated for the direct injection analysis of basic polar drugs in plasma by column‐switching liquid chromatography/mass spectrometry (LC/MS). Analytical conditions, including an automated pretreatment step and MS detection, were optimized for a series of basic drugs (doxepin, desipramine, imipramine, nortriptyline, amitriptyline, clomipramine). On‐line pretreatment with the MC‐SCX column followed by fast gradient analysis using a C18 column resulted in a total analysis cycle time of 7 min for each spiked plasma sample. More than 150 plasma samples spiked with target compounds were measured without compromising MS detection (relative standard deviations less than 11% for all compounds, and regression coefficients greater than 0.99). Copyright © 2005 John Wiley & Sons, Ltd.
Effect of Hydrothermal Treatment on Formation and Structural Characteristics of Slowly Digestible Non‐pasted Granular Sweet Potato Starch
Authors: Shin Sang Ick , Kim Ho Jong , Ha Hyo Jeong , Lee Seung Hee , Moon Tae Wha
Published: September 2005

The formation and structural characteristics of slowly digestible non‐pasted granular starch in sweet potato starch were investigated under various hydrothermal treatment conditions. The moisture content of the sweet potato starch was adjusted to 20, 50 or 90%, and the starch was heated at 40, 55 or 100°C for 12 h in a dry oven. The relative crystallinity of the hydrothermally treated samples was decreased with increasing temperature, and the X‐ray diffraction patterns of the samples were altered from Cb‐type to A‐type. Microscopic observations did not reveal any changes in the starch granules of any samples except those with moisture contents of 50 and 90% that were heated at 100°C. When gelatinization parameters were examined, samples with moisture contents of 50 and 90% that were heated at 55°C and samples of all moisture contents that were heated at 100°C had peak temperatures higher than that of raw starch but gelatinization enthalpies lower than that of raw starch. The swelling factor of the samples heated at 40°C did not change significantly, whereas that of samples heated at 55 and 100°C was decreased at increased moisture levels. The sweet potato starch with 50% moisture content that was heated at 55°C had the highest content of granular slowly digestible starch, about 200% that of raw starch, although our study did not involve further hydrothermal treatment conditions. Further study is required to complete a process for more efficient production of heat stable and slowly digestible starch.
Chemical and Functional Properties of Phaseolus lunatus and Manihot esculenta Starch Blends
Authors: Novelo‐Cen Loraine , Betancur‐Ancona David
Published: September 2005

Chemical and functional characteristics were determined for Phaseolus lunatus (P) and Manihot esculenta (M) starches, and blends of these two starches (25P/75M, 50P/50M, 75P/25M (%, w/w)). Starch purity varied from 95 to 98%. The lowest amylose content was in M. esculenta (17.3%) and the highest in P. lunatus (32.4%) with the blends having intermediate values. Total dietary fiber content in M. esculenta was 1.7%, and 1.2% in P. lunatus; of the blends the 25P/75M had the highest percentage (2.3%). Initial gelatinization temperature was higher for P. lunatus (67.9°C) than for M. esculenta (57.6°C), with the blends having intermediate values. P. lunatus starch had the highest retrogradation value (8.3 mL/50 g starch) of all the starches, while M. esculenta and the 25P/75M blend had no retrogradation at all. The P. lunatus paste had the highest viscosity (125.5 mPa s) compared to the other pastes, which were statistically similar (P>0.05). Gel clarity was lower in P. lunatus (23.84%T) than in M. esculenta (51.76%T), with intermediate values in the blends. The 25P/75M blend was selected as having the best combination of characteristics, since it showed not retrogradation, had high viscosity (102 mPa s), and was stable in the heating‐cooling cycle. This makes it a starch with suitable functional properties for use in a variety of foods. These results suggest that blending native starches from different vegetable sources improves their properties.
Cell proliferation in the cranial base of A/J mice with 6‐AN‐induced cleft palate
Authors: Long Sally Y. , Larsson K. Sune , Lohmander Stefan
Published: September 2005

Midsagittal sections of the heads of day 14.5–15.0 control A/J mouse fetuses revealed three areas of rapidly growing cartilage in the cranial base:mesethmoid, presphenoid, and craniopharyngeal. There was a curvature in the presphenoid, which straightened by the time of palatine shelf movement In fetuses of females treated with 6‐aminonicotinamide (6‐AN) on gestation day 13 the presphenoid had not straightened by day 15.5 and these fetuses all had cleft palate. In nontreated mice with spontaneous cleft lip and palate the presphenoid straightening was not impaired. Autoradiographs of [3H] thymidine uptake in the cranial base of experimental fetuses revealed selective impairment of cell proliferation in the presphenoid as judged by a significant decrease in labeled nuclei. It is proposed that straightening of the presphenoid is necessary for palatine shelf movement and normal palate closure.
Estimation of hydrocortisone dose and optimal gestation period for cleft palate induction in golden hamsters
Authors: Chaudhry A. P. , Shah R. M.
Published: September 2005

Thirty milligrams of hydrocortisone administered im to pregnant golden hamsters at gestation day 10:20 (i.e., 10 days, 20 h postconception), 11:00, or 11:04 produced 91, 100, and 100% cleft palate, respectively. Smaller doses (15, 20, or 25 mg) produced higher incidences of cleft palate at day 11:00 than 10:20 or 11:04, indicating that day 11:00 is the optimal time for yield of cleft palate with this system.
Strain differences in susceptibility to the teratogenic effect of acetazolamide in mice
Authors: Green Margaret C. , Azar Catherine A. , Maren Thomas H.
Published: September 2005

Intraperitoneal administration of acetazolamide to pregnant female mice on day 9 or 10 of gestation (750 mg/kg given twice, at 10 AM and 4 PM) produced postaxial abnormalities of the forelimbs with high frequency in the CBA/J and C57BL/6J strains, intermediate frequency in A/J and DBA/2J, and low frequency in C3H/HeJ and SWR/J. CBA/J was most susceptible to treatment on day 10, A/J on days 9 and 10, and C57BL/6J and C3H/HeJ on day 9. There was no reduction in amount of amniotic fluid 4 h after the last injection.
Spatial relations in the oral cavity of cortisone‐treated mouse fetuses during the time of secondary palate closure
Authors: Greene R. M. , Kochhar D. M.
Published: September 2005

Cortisone has long been used experimentally to induce cleft palate in mice, but the mechanisms by which it causes this effect remain controversial. It has been repeatedly demonstrated that after administration of cortisone the movement of the palatal shelves from a vertical to a horizontal position is delayed. The long‐accepted hypothesis is that during this delay growth of the head continues so that when the palatal shelves finally do become horizontal they are too far apart to meet in the midline and fuse. We found that maternally administered cortisone induced 95% cleft palate in ICR/DUB mouse fetuses observed at days 15–18 of gestation. Observations made on frozen, cryostat‐cut sections of fetal heads during the time of palate closure indicated that shelf elevation in experimental animals was delayed by as much as 12–14 h. However, when the shelves finally reached the horizontal they made contact with both the nasal septum and each other. It seems therefore that cortisone, beside causing delay in self movement, may also interfere with processes that occur subsequent to horizontalization leading to shelf fusion.
The effect of thalidomide intake during 113 human pregnancies
Authors: Kajii T. , Kida M. , Takahashi K.
Published: September 2005

Thalidomide was taken by 113 pregnant women during August 1959 to December 1961. Of these, only seven women took the drug during the critical period, i.e., between the 34th and 50th day after the last menstrual period. Three of them delivered malformed babies, including one spontaneously aborted by the 101st day after the last menstrual period. The remaining four women had children without apparent malformations. Two of the four children were reexamined by the age of 11 years. Rentgenograms were taken of the entire skeleton, and no malformation attributable to thalidomide was found. The first day of thalidomide intake in these four cases ranged from the 46th–49th day after the last menstrual period. It seems that a “thalidomide‐resistant pregnancy” occurred in some of the cases in which the drug was taken only by the 46th day or later in the critical period. In the case of two other women, thalidomide was taken earlier than the critical period: one by the 19th day and the other by the 23rd. The former underwent an induced abortion, and the latter had a spontaneous abortion by the 49th day. In the remaining 104 cases, in which thalidomide was prescribed later than the critical period, the offspring were apparently normal, except for one case of anal stenosis.
Teratogenic effects of carcinogen implantation in a regenerative field in Bufo arenarum tadpoles
Authors: Matos Elena L. , De Lustig Eugenia S.
Published: September 2005

Implantation of 20‐methylcholanthrene (MC), 3,4 benzopyrerne (BP), and 7,12‐dimethylbenz [a] anthracene in the tail of Bufo arenarum tadpoles induced toratogenic effects as well as lymphocyte or pleomorphic cell nodule formation. The development of nodules was modified by a regenerative field. The incidence and intensity of the teratogenic effects (supernumerary fins, accessory notochords—the latter reported here for the first time in amphibia) were enhanced by a regenerative field caused by tail amputation. MC and BP produced only supernumerary fins, and did so infrequently; whereas DMBA produced both defects, and in relative large frequencies.