bluuebunny/crossref_metadata_2025 huggingface dataset:
High rate of centrosome aberrations and correlation with proliferative activity in patients with untreated B‐cell chronic lymphocytic leukemia
Authors: Hensel Manfred , Zoz Martin , Giesecke Christian , Benner Axel , Neben Kai , Jauch Anna , Stilgenbauer Stephan , Ho Anthony D. , Krämer Alwin
Published: April 2007

B‐cell chronic lymphocytic leukemia (CLL) is characterized by a high rate of clonal genomic alterations and a low proliferative activity with cell cycle arrest in G0/G1phase. Recently, centrosome aberrations have been described as a possible cause of chromosomal instability and aneuploidy in many human malignancies. To investigate whether centrosome aberrations do occur in CLL and whether they correlate with common prognostic factors and disease activity, we examined peripheral blood mononuclear cells (PBMC) from 70 patients with previously untreated CLL using an antibody to γ‐tubulin. All 70 CLL samples displayed significantly more cells with centrosome aberrations (median: 26.0%, range 11.0–41.5%) as compared to peripheral blood B lymphocytes from 20 age‐matched, healthy individuals (median: 2.0%, range 0–6%;p< 0.001). The extent of centrosome aberrations correlated with the proliferative activity of the CLL cases as measured by lymphocyte doubling time (p= 0.02) as well as with time to first treatment (p= 0.05). Accordingly, more centrosome aberrations were found in PHA‐stimulated T lymphocytes from healthy individuals as well as in B cells from surgically removed tonsil tissue of patients with acute tonsillitis as compared to the peripheral blood B lymphocytes from the control group. In contrast, no correlation was observed between centrosome aberrations andimmunoglobulin VH genemutation status or cytogenetically defined risk groups. These findings suggest that, despite the common observation of most CLL cells remaining in G0/G1phase, their centrosome replication process is deregulated and correlates to the proliferative activity of CLL cells. © 2007 Wiley‐Liss, Inc.
Postnatal evaluation of schizencephaly by transfontanellar three‐dimensional sonography
Authors: Júnior Edward Araujo , Leite Alexis Paiva , Pires Cláudio Rodrigues , Filho Hélio Antonio Guimarães , Filho Sebastião Marques Zanforlin , Nardozza Luciano Marcondes Machado , Moron Antonio Fernades
Published: April 2007

Schizencephaly is a rare anomaly of neuronal migration characterized by the presence of brain clefts that communicate with the lateral ventricles. Type I is characterized by clefts with fused lips or margins, not communicating with the subarachnoid space. Type II is characterized by longer clefts that communicate with the subarachnoid space. Neonatal diagnosis of schizencephaly on transfontanellar two‐dimensional (2D) sonography is rare, with only 1 report in the medical literature. The major limitation of 2D sonography is its inability to assess neonatal prognosis. There are no reports on MEDLINE about the use of transfontanellar three‐dimensional (3D) sonography in the assessment of schizencephaly. We present a case of type II schizencephaly diagnosed on the 29th week of gestation with 2D sonography and describe the main findings with 3D sonography in surface and transparency modes performed in the neonatal period via the fontanel. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Sonographic spectrum of scrotal abnormalities in infertile men
Authors: Qublan Hussein S. , Al‐Okoor Khalil , Al‐Ghoweri Ahmad S. , Abu‐Qamar Adnan
Published: April 2007

Purpose.

To use sonography to detect scrotal abnormalities in infertile men.

Material and Methods.

Two hundred thirty‐four infertile men, including 176 oligospermic (sperm count < 10 × 106/ml), 58 azoospermic, and 150 normospermic men (control group) were evaluated prospectively for the presence of intra‐ and extratesticular abnormalities using high‐frequency transducers and color Doppler imaging. Medical and surgical history, testicular volume, semen parameters, and hormonal levels were recorded.

Results.

A statistically significant increase in the prevalence of abnormal scrotal findings detected with sonography was observed in the study group compared with controls. These included variocele in 35.5% versus 16% (p < 0.01), hydrocele in 16.7% versus 8.7% (p < 0.05), testicular microlithiasis in 9.8% versus 2% (p < 0.01), epididymal enlargement in 9% versus 2.6% (p < 0.05), and epididymal cyst in 7.7% versus 2% (p < 0.05). Testicular tumor was not seen in either group. A statistically significant decrease in testicular volume, sperm concentration, normal morphology, and forward motility of the sperm was noted in the study group compared with controls (p < 0.01).

Conclusion.

The various intra‐ and extratesticular abnormalities were demonstrated in infertile men. Sonography should be used routinely in the work‐up of male infertility. © 2007 Wiley Periodicals, Inc. J Clin Ultrasound, 2007
Comparative anatomy, homologies and evolution of the pectoral muscles of bony fish and tetrapods: A new insight
Authors: Diogo Rui , Abdala Virginia
Published: April 2007

The Osteichthyes, including bony fishes and tetrapods, is a highly speciose group of vertebrates, comprising more than 42,000 living species. The anatomy of osteichthyans has been the subject of numerous comparative studies, but most of these studies concern osteological structures; much less attention has been paid to muscles. The most detailed comparative analyses of osteichthyan pectoral muscles that were actually based on a direct observation of representatives of various major actinopterygian and sarcopterygian groups were provided several decades ago by authors such as Howell and Romer. Despite the quality of their work, these authors did not have access to much information that is now available. In the present work, an updated discussion on the homologies and evolution of the osteichthyan pectoral muscles is provided, based on the authors' own analyses and on a survey of the literature, both old and recent. It is stressed that much caution should be taken when the results obtained in molecular and developmental studies concerning the pectoral muscles of model actinopterygians such as the teleostean zebrafish are discussed and compared with the results obtained in studies concerning model sarcopterygians from clades such as the Amphibia and/or the Amniota. This is because, as shown here, as a result of the different evolutionary routes followed within the actinopterygian and the sarcopterygian clades none of the individual muscles found, for example, in derived actinopterygians such as teleosts is found in derived sarcopterygians such as tetrapods. It is hoped that the information provided in the present work may help in paving the way for future analyses of the pectoral muscles in taxa from different osteichthyan groups and for a proper comparison between these muscles in those taxa. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.
Effects of television brand placement on brand image
Authors: van Reijmersdal Eva A. , Neijens Peter C. , Smit Edith G.
Published: April 2007

A survey as well as an experiment was conducted to study the effects of television brand placement on brand image. The studies showed that the integration of a brand into the editorial content of a program had a significant effect on brand image: As people watched more episodes, the brand image became more in agreement with the program image. These results confirm the applicability of learning and human associative memory theories to brand placement. Another important finding is that brand memory and brand image were not related. Thus, brand image became more positive regardless of viewers' memory of the brand placements, which implies that brand image was implicitly affected. This has important theoretical implications for the understanding of the working of brand placement. © 2007 Wiley Periodicals, Inc.
Nucleolar development and allocation of key nucleolar proteins require de novo transcription in bovine embryos
Authors: Svarcova Olga , Laurincik Jozef , Avery Birthe , Mlyncek Milos , Niemann Heiner , Maddox‐Hyttel Poul
Published: April 2007

The goal of the present study was to investigate whether key nucleolar proteins involved in ribosomal RNA (rRNA) transcription and processing are transcribed de novo or from maternally inherited messenger RNAs (mRNA) in bovine embryos, and to which extent de novo transcription of these proteins mRNA is required for the development of functional nucleoli during the major activation of the embryonic genome. Immunofluorescence for localization of key nucleolar proteins, autoradiography for detection of transcriptional activity, and transmission electron microscopy were applied to in vitro produced bovine embryos cultured from the 2‐cell stage with or without (control groups) α‐amanitin, which blocks the RNA polymerases II and III transcription and, thus the synthesis of mRNA. In the control groups, weak autoradiographic labeling was initially observed in the periphery of few nuclei at the 4‐cell and the early 8‐cell stage, and the entire nucleoplasm as well as nucleolus precursor bodies (NBBs) were prominently labelled in all late 8‐cell stages. The NPBs displayed initial transformation into fibrillo‐granular nucleoli. In the α‐amanitin group, lack of autoradiographic labeling was seen at all developmental stages and disintegrated NPBs stage were found at the late 8‐cell. Our immunofluorescence data indicate that RNA polymerase I, UBF, topoisomerase I and fibrillarin are transcribed de novo whereas nucleolin and nucleophosmin are maternally inherited as demonstrated by α ‐amanitin inhibition. However, localization of these two proteins to the nucleolar compartments was negatively affected by the α‐amanitin treatment. Consequently, functional nucleoli were not established. Mol. Reprod. Dev. 74: 1428–1435, 2007. © 2007 Wiley‐Liss, Inc.
Successful treatment of refractory immune hemolysis following unrelated cord blood transplant with Campath‐1H
Authors: Chao Mwe Mwe , Levine John E. , Ferrara James L. , Cooling Laura , Cooke Kenneth R. , Hutchinson Raymond J. , Yanik Gregory A.
Published: April 2007

Immune‐mediated hemolytic anemia is a well‐recognized complication of hematopoietic stem cell transplantation. We report on a 6‐year‐old boy with X‐linked adrenoleukodystrophy who developed severe delayed alloimmune hemolytic anemia associated with immune‐mediated neutropenia and thrombocytopenia following major ABO incompatible unrelated cord blood transplantation. The patient's cytopenias were refractory to treatment with corticosteroids, cyclosporine, intravenous immune globulin, rituximab, and pentostatin. After one course of Campath‐1H his hematologic parameters normalized, suggesting that the compound may be an effective therapy for complex immunohematologic disorders complicating hematopoietic stem cell transplantation. The case also emphasizes the importance of T‐cells in transplant associated immune cytopenias. Pediatr Blood Cancer 2008;50:917–919. © 2007 Wiley‐Liss, Inc.
Precursor natural killer cell leukemia
Authors: Liang Xiayuan , Greffe Brian , Garrington Timothy , Graham Douglas K.
Published: April 2007

Natural killer (NK) cell tumors are a rare and heterogeneous group of disorders. Immature NK cell tumors are less common, and are less recognized and defined than mature NK cell tumors. There is insufficient experience of diagnosis and treatment with immature NK cell tumors, especially in pediatric patients. Here we describe a pediatric patient with precursor NK cell leukemia and review the literature of the previously reported cases in children to further help characterize the diagnosis, treatment, and outcome. Pediatr Blood Cancer 2008;50:876–878. © 2007 Wiley‐Liss, Inc.
Significance of pleural effusion in neuroblastoma
Authors: Gupta Himesh , Conrad John , Khoury Joseph D. , McGregor Lisa M. , Krasin Matthew J. , Dome Jeffrey S. , Santana Victor M. , Davidoff Andrew M.
Published: April 2007

Background

Pleural effusion is uncommon at diagnosis of neuroblastoma in children. Because the presence of malignant cells in pleural fluid may significantly change the management and outcome of patients with neuroblastoma, we retrospectively analyzed a cohort of neuroblastoma patients who presented with pleural effusion at the time of diagnosis to determine the incidence, presentation, stage, treatment, and outcome of these patients.

Methods

We reviewed the presenting features of 295 patients with the diagnosis of neuroblastoma who received treatment at St. Jude Children's Research Hospital between 1991 and 2005. Patients were chosen for further analysis if pleural effusion had been identified on chest radiographs or computed tomography (CT) scans at diagnosis

Results

Thirty‐one out of 295(10.5%) patients with neuroblastoma had pleural effusion identified at time of presentation. International neuroblastoma staging system (INSS) risk stratification was high risk in 29 cases and intermediate risk and low risk in 1 case each. The primary site of disease was abdomen in 26 patients; mediastinum in 5. We conducted cytologic analysis of pleural fluid of nine patients; the specimen of seven contained malignant cells. Eighteen of 31 patients died of progressive or recurrent disease.

Conclusion

In patients with neuroblastoma, pleural effusion is usually associated with unfavorable biologic features and high‐risk disease. Pleural fluid should be examined cytologically and at a time when the results would change the risk stratification. There was no statistically significant difference in the survival rate of the patients with high‐risk neuroblastoma with or without malignant pleural effusion. Pediatr Blood Cancer 2007;49:906–908. © 2007 Wiley‐Liss, Inc.
Calculations of diffusion coefficients of cyclic poly(dimethylsiloxanes)
Authors: Dodgson Keith , Edwards Christopher J. C. , Stepto Robert F. T.
Published: April 2007

The Kirkwood equation and a Monte‐Carlo technique which employs Metropolis sampling have been used to calculate diffusion coefficients (D) for low molar mass cyclic poly(dimethylsiloxanes). Correlations between calculated and experimental values of D show that the effective segment size is larger for cyclic than for linear PDMS. Thus, free‐draining flow is reduced for the cyclic species consistent with its greater segment density. The cyclic molecules also show enhanced diffusion coefficients at very low molar masses which may be associated with the rigid toroidal shapes of these molecules.
The molecular characteristics of hydroxyl‐terminated polybutadiene
Authors: Regan Peter R. , Teo Hoon Hong , Booth Colin , Cunliffe Anthony V. , Hudd Alan L.
Published: April 2007

Three samples of a commercial hydroxyl‐terminated polybutadiene, Arco R45M. were characterised with respect to number‐average and weight‐average molar mass, intrinsic viscosity, number‐average hydroxyl functionality and effective functionality for gelation. Two of the samples were fractionated on the basis of solubility in toluene/methanol mixtures, and the fractions were characterised with respect to number‐average molar mass, intrinsic viscosity and number‐average hydroxyl functionality. For both sets of fractions, the average functionality was practically independent of average molar mass. It is concluded that the functionality distribution is almost identical at all points in the molar mass range of Arco R45M.
End‐groups in polymers of 2‐vinylnaphthalene and 4‐vinylbiphenyl, prepared by polymerisations initiated by azobis(isobutyronitrile)
Authors: Bevington John C. , Huckerby Thomas N. , Hunt Barry J.
Published: April 2007

Polymerisations of 2‐vinylnaphthalene and 4‐vinylbiphenyl and copolymerisations of these monomers with methyl methacrylate have been initiated by azobis(isobutyronitrile) enriched in its methyl groups with carbon‐13. The environments of (CH3)2C(CN)‐ end‐groups in the copolymers have been examined by 13C nuclear magnetic resonance. It has been concluded that both aromatic monomers are more than twice as reactive as methyl methacrylate towards the primary radical.
The concentration dependence of biopolymer gel modulus
Authors: Clark Allan H. , Ross‐Murphy Simon B.
Published: April 2007

Gel formation from aqueous biopolymer solutions is a common phenomenon and one of practical importance, yet it is much less well understood and characterised than the condensation of synthetic polymer precursors to form networks. There are many reasons for this, including the complexity of the aggregating species, the diversity of crosslinking mechanisms, the physical nature of the attractive forces, and the complexities introduced by having water as a solvent. In the present paper, however, an attempt is made to adapt classical theories of gelation and of rubber elasticity to treat the biopolymer case and to describe the shear modulus‐versus‐concentration behaviour of such non‐ideal materials. Modulus data for cold‐set gels formed from the polysaccharide agar and the protein gelatin are presented and analysed, as are similar data for substantially different gels formed by heating solutions of globular proteins. It is demonstrated how, by assuming a crosslinking equilibrium, such diverse sets of data can be reduced to a dimensionless master curve form, and the limiting concentration dependence of the modulus at high concentration is discussed in the light of the present work and of a recent theoretical description based on the osmotic scaling relationship.
The condensation of lignin model compounds with hexamethylene diisocyanate
Authors: Detoisien Marlène , Pla Fernand , Gandini Alessandro , Cheradame Hervé , Monzie Pierre
Published: April 2007

Analysis by infrared and nuclear magnetic resonance spectroscopy, differential scanning calorimetry and thermogravimetric estimation of the condensation products of hexamethylene diisocyanate and certain lignin model compounds bearing a free phenolic hydroxyl (prepared both in the melt at 100°C and in refluxing methylene chloride solution) shows that stoichiometric proportions give high yields of bisurethanes. These products decompose below 160°C to regenerate the starting materials.
The effect of additives on the thermal stability of poly(vinyl chloride)
Authors: Manley T. R. , Guy A. , Clark L. J.
Published: April 2007

The effect of a range of organic additives on the thermal stability of poly(vinyl chloride), both with and without a chloroparaffin extender, was studied using a number of experimental techniques. Of the additives used the best overall balance was provided by pentaerythritol, which increased stability when the extender was present and had no effect when it was absent. The congo red test emerged as the most suitable technique, being consistent and inexpensive and able to screen several additives simultaneously. Isothermal differential thermal analysis correlated with the congo red test but required more expensive equipment, was time‐consuming and demanded good mixing of the poly(vinyl chloride) compound to give reproducible results. Thermogravimetry was not sufficiently sensitive and the heat stability test was the least useful of all.
Differential Scanning Calorimetry Cure Studies of Tetra‐N‐glycidyldiaminodiphenylmethane Epoxy Resins. Part 1 ‐ Reaction with 4,4′‐Diaminodiphenylsulphone
Authors: Barton John M.
Published: April 2007

Rates and extents of cure are determined using differential scanning calorimetry in the isothermal mode over the temperature range 170–220°C, and from d.s.c. scans at various heating rates. The isothermal data are consistent with an autocatalytic mechanism at conversions up to about 20–30%. Data from d.s.c. scans fit a simple kinetic model which indicates that the apparent activation energy (E) for cure increases with increasing conversion, consistent with an increasing degree of diffusion control. At low levels of conversion the isothermal and dynamic data both provide estimates for E of about 70 kJ mol−1. The heat of cure is about 105 kJ mol−1 epoxide, and is constant over a wide range of amine concentration. This indicates that any parallel or competing processes which occur must have the same heat of reaction.
Differential Scanning Calorimetry Cure Studies of Tetra‐N‐glycidyldiaminodiphenylmethane Epoxy Resins Part 2 ‐ Reaction with 4,4′‐Diaminodiphenylsulphone Accelerated by Borontriofluoride‐Ethylamine
Authors: Barton John M.
Published: April 2007

The curing reaction was monitored by differential scanning calorimetry scans at various heating rates and from isothermal experiments in the range 130–170°C. The catalysed isothermal cure is an initially rapid reaction which approximates to first‐order kinetics. Above about 30% conversion there is a transition to a much slower first‐order reaction. The differential scanning calorimetry scans show multiple exotherm peaks, indicative of a complex reaction. However, data at a given conversion can be described by a simple general kinetic model. The heat of reaction shows a decreasing trend with increasing catalyst concentration.
The Adsorption of a Polystyrene‐b‐Polyisoprene Block Copolymer at the n‐Hexadecane/Air Interface
Authors: Price Colin , Chan Eddie K. M. , Hudd Alan L. , Stubbersfield Rita B.
Published: April 2007

Surface‐tension measurements were used to investigate the surface adsorption and micellisation of a polystyrene‐b‐polyisoprene block copolymer in n‐hexadecane which is a selectively bad solvent for polystyrene. Measurements were made over a range of concentrations (1.29–2.88)x10−4 mol dm−3 and temperatures 25–40°C. The block copolymer was found to be positively adsorbed at the n‐hexadecane/air interface. The linearity of plots of γ against In c just below the critical micelle concentration (c.m.c.) indicated an approximately constant surface concentration. The area per block copolymer molecule at the surface had an average value of 4.1 nm2. A plot of In (c.m.c.) against T−1 gave a value for the standard enthalpy of micellisation of ‐41.9.3.0 kJ per mole of copolymer chains. The standard entropy contribution (‐TΔSΔ) to the standard free energy of micellisation was found to be 19.7.3.0 kJ mol−1. These thermodynamic values are in good agreement with results obtained earlier for this system by light scattering and calorimetry.
Ionic conductivity of polymer electrolytes and future applications
Authors: Watanabe Masayoshi , Ogata Naoya
Published: April 2007

Polymer electrolytes are solvent‐free ion‐conducting polymers and provide new and attractive materials in both polymer chemistry and electrochemistry. A proper understanding of ion dissociation and ion transport in such polymers is necessary for their application as solid electrolytes in electrochemical devices. Ionic conduction behaviour in polymer electrolytes is described here in relation to the characteristic properties. Of special interest is the ability of polymer electrolytes to include various kinds of electroactive molecules within them. The combination of this ability with their high ionic conductivity has enabled polymer electrolytes to be used as media for electrochemical syntheses and redox reactions.
Preliminary results on a new polymer electrolyte, poly(ethyleneoxide)‐Hg(CIO4)2
Authors: Bruce Peter G. , Krok Franciszek , Evans James , Vincent Colin A.
Published: April 2007

A new solid polymer electrolyte, poly(ethylene oxide)‐Hg(ClO4)2, has been prepared with the ratio of ethylene oxide units to mercury ions ranging from 4 to 20. The variation of conductivity with temperature does not follow a simple Arrhenius law. At high salt concentrations the films are entirely amorphous.
Radiotracer self‐diffusion measurements in poly(ethylene oxide) and poly(propylene oxide) electrolytes
Authors: Bridges Christopher , Chadwick Alan V. , Worboys Michael R.
Published: April 2007

Radiotracer measurements of the 22Na+ and S14CN− diffusion coefficients in PEO‐NaSCN (x = 6, 8 and 12) and PPO‐NaSCN (x = 8) are reported, where PEO = poly(ethylene oxide), PPO = poly(propylene oxide), and x = [EO units]/[NaSCN] or [PO units]/[NaSCN]. The results are compared with ionic conductivity measurements on the same samples. Measurements for the PEO samples were taken above the melting point of pure PEO and the results interpreted, particularly for the sample most dilute in salt, in terms of ‘free ions’ as the dominant charge carriers. For PPO the results are less clear, although there is good evidence for the onset of ion aggregation prior to separation of salt at higher temperatures.
Self‐diffusion of ions in an ethylene oxide oligomer using the gelsectioning technique
Authors: Al‐Mudaris Arkan A. , Chadwick Alan V.
Published: April 2007

The gel‐sectioning technique has been used to measure the radiotracer diffusion coefficients of Na+ and SCN− ions in solutions of sodium thiocyanate in tetra(ethylene glycol) dimethyl ether (‘tetraglyme’), a liquid system which can be used as a model polymer electrolyte. Measurements were made at 298 K over the molar concentration range tetraglyme‐NaSCN between 2.5 and 50. At all concentrations the diffusion coefficients of both ions were virtually identical and decreased markedly at high salt concentrations. Comparison of the diffusion results with conductivity measurements on the same samples gives evidence for the aggregation of ions at low salt concentrations (tetraglyme‐NaSCN > 20). At higher salt concentrations aggregation does not need to be invoked to explain the results. The implications for other polyether electrolytes are discussed.
High frequency impedance of poly(ethylene oxide) and related polymers doped with lithium perchlorate
Authors: Linden E. , Owen J. R.
Published: April 2007

High frequency complex impedance measurements at room temperature have been used to obtain dielectric constants, sample dimension ratios and conductivities for poly(ethylene oxide), PEO, and poly(propylene oxide), PPO, doped with LiClO4. The corrections required to compensate for artefacts due to instrumentation (leads, cables, etc.) at high frequencies are presented. It is concluded that an area/length ratio (A/l) of about 300 cm is preferable for high frequency work. Dielectric constants varied by less than an order of magnitude over a variety of samples, so that the conductivity of an irregularly shaped sample can be estimated from the dielectric relaxation frequency. It was also concluded that the depression of the impedance semicircle for semi‐crystalline PEO was due mainly to the microstructure.
Poly(ethylene oxide)‐sodium perchlorate electrolytes in solid‐state sodium cells
Authors: West Keld , Zachau‐Christiansen Birgit , Jacobsen Torben , Hiort‐Lorenzen Emil , Skaarup Steen
Published: April 2007

The behaviour of poly(ethylene oxide)‐sodium perchlorate as electrolyte in solid‐state batteries was characterized by impedance spectroscopy with respect to the conductivity and chemical reactivity of the sodium/polymer interface. Formation of a corrosion layer on the sodium electrode was found, and the growth of this layer was followed during open circuit and cycling conditions. It is concluded that the surface resistance is a major contribution to the cell impedance.
Ionic conductivity in mixtures of salts with comb‐shaped polymers based on ethylene oxide macromers
Authors: Cowie John M. G. , Martin Agnes C. S. , Firth Anne‐Marie
Published: April 2007

A comb‐shaped polymer was prepared from a vinyl ether monomer comprising three oxyethylene units with a terminal methoxy group. The polymer could dissolve LiClO4, NaClO4, and LiSO3CF3 salts to form homogeneous amorphous mixtures, and the glass transition temperatures in each system were observed to increase with added salt. A.c. conductivity studies on the mixtures of polymer‐LiClO4 showed a dependence on both salt concentration and temperature. Room temperature conductivities were around 10−5Scm−1 rising to about 10−3Scm−1 at ∼ 380K. A maximum in the conductivity was detected which altered with temperature. Conductivities which displayed non‐Arrhenius behaviour were analysed using the Vogel‐Tammann‐Fulcher equation and interpreted on the basis of the configurational entropy model derived by Gibbs and coworkers.
Crosslinked polyethers as media for ionic conduction
Authors: Nest Jean‐Francois Le , Gandini Alessandro , Cheradame Hervé
Published: April 2007

A broad outline is given of a comprehensive investigation dealing with solid polymeric electrolytes containing ionic species. These materials are based on various types of polyethers (homopolymers, block and graft copolymers) crosslinked via urethane chemistry and either filled with a salt or transformed into ionomers with the anions attached to the chains. The properties studied were specific volume, swelling, glass transition temperature, viscoelasticity, ionic conductivity, transport numbers, magnetic relaxation of nuclei from both the polymer chains and the ions, and redox stability. Mechanisms and models are proposed to explain chain partitioning by cations and the mode of ionic transport. An all‐solid‐state battery was prepared with one of these materials to prove its good performance.
Solid polymer electrolytes with stable electrochemical properties
Authors: Carré Claudine , Hamaide Thierry , Guyot Alain , Mai Christian
Published: April 2007

In order to build solid‐state ambient‐temperature batteries with stable electrochemical performances over a period of months, the crystallization process in polymer electrolytes can be suppressed by the addition of an elastomer and a styrenic macromonomer of PEO to a PEO‐lithium salt electrolyte. Complex impedance measurements and X‐ray diffraction studies were carried out in an attempt to understand the effect of the macromonomer on the electrochemical behaviour. The conductivity was found to increase with macromonomer content and values as high as 10−5S cm−1 at room temperature can be obtained. X‐ray, diffraction patterns have shown that addition of the elastomer and the macromonomer does not alter the monoclinic unit cell of the crystallized PEO. During ageing, the diffraction lines were found not to vary appreciably over a period of 15 months. Similarly, no appreciable change in the conductivity level was noticed within the same period. The observed behaviour was explained as a suppression of the crystallization process.
The conductivity behaviour of gamma‐irradiated PEO‐LiX electrolytes. I
Authors: Kronfli Esam , Lovell Keith V. , Hooper Alan , Neat Robin J.
Published: April 2007

In an attempt to enhance the room temperature ionic conductivity of PEO‐LiX films, samples have been exposed to gamma‐irradiation at 78°C. The success with which cross‐links have been introduced into the amorphous form has been evaluated from d.s.c. analysis and temperature‐dependent conductivity data. Retardation of the recrystallisation event, associated with uncomplexed poly(ethylene oxide), does not occur over a range of total doses. Changes in overall conductivity levels for the PEO‐LiCF3SO3 ([EO units]/[Li] = 9) system, indicate light cross‐linking at 2.25 Mrad of exposure. However, higher doses result in a substantial amount of chain scission, leading eventually to poor mechanical properties. A similar study on PEO‐LiClO4 ([EO units]/[Li] = 20) confirms that the above route is an ineffective method to improve room temperature conductivity.
Polymer electrolyte complexes of LiCIO4 and comb polymers of siloxane with oligo‐oxyethylene side chains
Authors: Fish Daryle , Khan Ishrat M. , Wu E. , Smid Johannes
Published: April 2007

Polysiloxanes with oligo‐oxyethylene side chains of the type —O(CH2CH2O)7CH3 and —(CH2)3O(CH2CH2O)nCH3 (average n ≈ 7 and 11) were synthesized from poly(hydrogenmethylsiloxane) and characterized by 1H n.m.r., 29Si n.m.r., i.r. and g.p.c. Cyclic analogues were used as model compounds and synthesized from tetramethylcyclotetrasiloxane. Polymer electrolyte complexes were made from the comb polymers and LiClO4 by solvent‐casting from THF, and their conductivities measured as a function of temperature and studied by differential scanning calorimetry and correlated with their conductivity behaviour. Maximum conductivities close to 10−4S cm−1 were achieved at room temperature and at ethylene oxide units to Li+ ratios of about 25. Cross‐linking or blending with high molecular weight poly(oxyethylene) lowers the conductance somewhat but vastly improves the mechanical properties of the complexes, and the blends with PEO can be cast into thin, flexible and tough films with good conducting properties.
Improved synthesis of oxymethylene‐linked poly(oxyethylene)
Authors: Nicholas Christian V. , Wilson David J. , Booth Colin , Giles Jeremy R. M.
Published: April 2007

Polyethylene glycol 400 was reacted with CH2Cl2 in the presence of KOH to form oxymethylene‐linked chains. The method gave a high yield of colourless high‐molecular‐weight elastomer. The ionic conductivity of a mixture of the polymer with LiCF3SO3 ([O]/[Li] = 25) was about 5 × 10−5S cm−1 at 25°C.
Monomer sequence determinations of aryl ether sulphone copolymers as determined by 13C n.m.r.
Authors: Bunn Alan
Published: April 2007

The monomer sequence distributions of three types of aryl ether sulphone copolymers have been determined by 13C n.m.r. spectroscopy. Two amorphous aryl ether sulphone copolymers were shown to have transetherified (or ether interchanged) during polymerisation to become random copolymers. The residues in these copolymers were (i)—OøOøSO2øS—and (ii)—OøSO2øøSO2ø—‐where ø denotes 1,4‐phenylene. Copolymers of 50:50 aryl ether sulphone and aryl ether ketone made from different combinations of monomers were found to have different solubilities in dimethyl sulphoxide, and from 13C n.m.r. data this was shown to correlate with the amount of transetherification which had taken place during the polymerisations. The 13C n.m.r. chemical shifts for some of the carbon nuclei in these polymers were sensititive to functional groups situated even as far away as three or four aromatic nuclei along the polymer chain.
Phase separation in non‐solvent/dimethylformamide/polyethersulphone and non‐solvent/dimethylformamide/polysulphone systems
Authors: Swinyard Brian T. , Barrie James A.
Published: April 2007

The cloud point curves for the ternary solutions non‐solvent/dimethyl‐formamide/polyethersulphone and non‐solvent/dimethylformamide/polysul‐phone were determined by a titration technique, at 303 K. In both systems the following order of increasing non‐solvent content at the cloud point was obtained: water < methanol < ethanol < 1‐propanol < acetone < carbon tetrachloride. For each non‐solvent the cloud point curve for the PES system occurred at higher non‐solvent concentrations than for the corresponding PSN system.
New production technologies and applications of poly(vinyl alcohol) film
Authors: Moroi Hiroyuki
Published: April 2007

The following aspects of the manufacture, properties and applications of biaxially oriented poly(vinyl alcohol) (PV‐OH) films are discussed: selection of starting PV‐OH; method of production by successive biaxial orientation: technical aspects of production; characteristics and applications of the film. Biaxially oriented PV‐OH films have good antistatic properties, good thermal resistance, oil and solvent resistance, and excellent gas barrier properties, and are used in food packaging applications.

The following aspects of the manufacture, properties and applications of poly(vinyl alcohol) film produced by a blown film technique are discussed: selection of starting PV‐OH; process for the production of hot‐water‐soluble (HWS) film; technical aspects of film production; characteristics and applications of the film. Blown films, which are hot‐water‐soluble, are produced in tubular form, for conversion into disposable laundry bags.
The influence of poly(vinyl alcohol) suspending agents on suspension poly(vinyl chloride) morphology
Authors: Ormondroyd Stephen
Published: April 2007

The requirements for PVC suspension resin have changed considerably in the last few years, so much so that few companies have products on their ranges that are more than 4 or 5 years old. The suspending agent has a crucial influence on the morphology of the resin, so the changes in resin characteristics have largely been achieved by changes in the suspending agent systems.

After a brief review of the mechanism of PVC suspension polymerisation, the properties of polymers made using PVOH suspending agents are related to changes in the latter. The effect of variations in PVAc degree of hydrolysis and viscosity are related to changes in surface tension. Methods of achieving higher porosity by using low hydrolysis co‐suspending agents are described. It is shown that higher bulk densities can be achieved by delayed addition of the PVOH. Levels of conjugated unsaturation and copolymer distributions are also shown to have important influences.
Inhibition period of vinyl acetate monomer in suspension, emulsion and bulk polymerization at 730mm Hg and 760 mm Hg
Authors: Rao Vyakaranam K. , Singh Rajendra P. , Bisarya Satish C.
Published: April 2007

A trend in the inhibition period of vinyl acetate monomer (VAM), using benzoyl peroxide (Bz2O2), azobisisobutyronitrile (AIBN) and potassium peroxy disulphate (K2S2O8), during suspension, emulsion and bulk polymerizations, with change in pressure from 730 mm Hg to 760 mm Hg, is reported.
PMR‐15 processing, properties and problems—a review
Authors: Wilson Douglas
Published: April 2007

The frontrunner in the race to develop a high temperature resin for use in advanced composites intended for high temperature applications is the NASA developed polyimide PMR‐15. One of the key factors in the success of the material is the relatively easy processing which is due mainly to the use of the PMR approach (Polymerisation of Monomeric Reactants). Prepreg and high quality composite laminates (glass or carbon) can be prepared with ease. Laminate properties compare well with conventional epoxy based systems but thermal stability is much greater. Continuous use temperatures are in the range 280‐300°C, some 150‐170°C higher than epoxy systems. Applications of PMR‐15 composites include aero‐engines, missiles, spacecraft and military aircraft. Despite being the leading system available today PMR‐15, like all materials, has a number of limitations affecting its widespread use. Included in these are reliable methods of quality control, prepreg batch to batch variability, microcracking from thermal cycling, health and safety hazards and high temperature processing. This paper reviews the present status of PMR‐15 development and outlines work designed to identify and where possible overcome these limitations.
Reaction mechanism, kinetics and network structure of the DGEBA‐DDS system
Authors: Grenier‐Loustalot Marie‐Florence , Grenier Philippe , Horny Patrick , Chenard Jean‐Yves
Published: April 2007

Different techniques were used to analyse the reaction mechanisms and kinetics of the system 2,2‐[4‐(2,3‐epoxypropyl)phenyl]propane polycondensed with 4,4′‐sulphonyl‐dianiline in the temperature range 100−185°C. The results show the role of catalysts, of stoichiometry and of curing cycles in the reaction mechanisms and paths.

Based on chemical balances of residual epoxy groups, and of hydroxy and ether groups formed, we have shown the effect of these functions on the thermal properties of the material.
Entrapping of acid phosphatase in poly(2‐hydroxyethyl methacrylate) matrices: Preparation and kinetic properties
Authors: Cantarella M. , Cantarella L. , Alfani F.
Published: April 2007

The present work was undertaken to determine the influence of immobilization of acid phosphatase by entrapment in poly(2‐hydroxyethyl methacrylate) (poly‐HEMA) gels on the rate and duration of p‐nitrophenyl phosphate hydrolysis. This enzyme was selected as model system for the sake of comparison with other immobilization techniques studied previously making use of natural polymers. Under certain conditions, catalyst inactivation induced by chemical agents employed during polymerization was very low. Activity recovery in the enzymatically filled hydrogels depends on acid phosphatase loading and attains a maximum at 2 mg per gram of support. The use of low molecular weight linear polymers as matrix fillers is advisable. The best results were achieved with poly(ethylene oxide) PEG 1500, but PEG 6000 and poly(N‐vinylpyrrolidone) PVP 10 000 are also effective. Bovine serum albumin (BSA) is useless. The highest value of activity recovery obtained was 24% that of free enzyme. Roughly 30% of enzyme is retained in active form in the hydrogel and works with an efficiency ranging from 97% to 90% depending on average particle size. The kinetic parameters Km and Ea suggest the presence of a combined diffusive and enzymatic reaction‐controlling mechanism. Only a minor shift of optimum pH was observed. Both operational and storage stability are largely improved upon entrapping in hydrogels.
Studies on the polymerization of propylene using high activity ziegler‐natta catalysts. 1: Kinetic models for rate decay in ziegler‐natta polymerization
Authors: Tait Peter J. T. , Wang Shemin
Published: April 2007

Kinetic models for describing the time dependence of the polymerization rate and active centre concentration for high activity Ziegler‐Natta catalyst systems are discussed. It is demonstrated that the decay in the rate of polymerization and in the concentration of active centres with time for the polymerization of propylene with the heterogeneous catalyst system MgCl2/EB/TiCl4Al(i‐Bu)3/EB can be represented better by a modified multi‐centre first order decay model than by the other models which are considered.
Morphology and mechanical properties of styrene‐butadiene‐styrene/polystyrene semi‐interpenetrating polymer networks and their blends
Authors: Shyu Shin‐Shing , Chao An‐Chong
Published: April 2007

SBS/PS semi‐interpenetrating polymer networks (semi‐IPNS) were synthesized by swelling a linear styrene‐butadiene‐styrene (SBS) triblock copolymer (SBS, Kraton 1102) with styrene monomer plus benzoin as photoinitiator and divinylbenzene as cross‐linking agent. Polyblends were prepared by solution casting of SBS and polystyrene (PS) in their ideal solvents. Measurements were made for viscoelastic properties and mechanical properties of phase‐separated polymer alloy (including SBS copolymers Kraton 4122), semi‐IPNs and polyblends of several SBS and PS, with the same total PS content (48% PS). The dynamic mechanical behaviour shows distinct transitions for each polymer, in agreement with electron microscopy results that SBS/PS polymer alloy forms two phases; however, the phase domains were finer in the semi‐IPNs than in SBS triblock copolymer and in polyblends of the corresponding polymers. Stress‐strain data show that semi‐IPNs exhibit higher tensile strength and modulus than the other two corresponding polymer alloys. A master curve was plotted to illustrate the stress relaxation behaviour of samples at higher temperatures. Our results also reveal that semi‐IPNs have much better high‐temperature mechanical strength.
Emulsion polymerisation of highly water‐insoluble monomers
Authors: Satpathy Uma S. , Dunn Alexander S.
Published: April 2007

Contrary to an earlier report, monomers (e.g. p‐tert‐butylstyrene and octadecyl methacrylate) which are less soluble in water than styrene have been found to polymerise in emulsion using persulphate initiation. At 60°C, the order of the Interval II polymerisation rate of octadecyl methacrylate is 0.48 in persulphate concentration and 0.68 in sodium dodecyl sulphate concentration. The rate is increased by addition of methanol to the aqueous phase. Unlike styrene, p‐tert‐butylstyrene could not be polymerised in aqueous suspension by persulphate in the absence of emulsifier. High emulsifier‐monomer ratios were used in these experiments so that it is possible that mini‐emulsion droplets were a significant reaction locus.
Interpenetrating polymer networks from castor oil based polyurethanes and poly(ethyl acrylate)
Authors: Patel Prashant , Patel Mayur , Suthar Bhikhu
Published: April 2007

Polyurethanes were obtained by the reaction of hydroxyl groups of castor oil with hexamethylene diisocyanate, isophorone diisocyanate or diphenylmethane diisocyanate using an NCO/OH ratio of 1.6. These polyurethanes were swollen in ethyl acrylate monomer and subsequently polymerized by radical polymerization initiated with benzoyl peroxide in the presence of the crosslinking agent ethylene glycol dimethacrylate. A series of interpenetrating polymer networks (PU/PEA IPNs) were obtained as tough films by casting in glass moulds. The characteristics of these films were determined: resistance to chemical reagents, thermal behaviour (DSC, TGA), tensile strength, Young's modulus, elongation at break (%) and Shore A hardness. The morphology was determined by scanning electron microscopy, and the dielectric properties such as electrical conductivity, dielectric constant (ε′), dielectric loss (ε″) and loss tangent (tan δ) were studied.
Synthesis of poly (p‐methylstyrene) ‐ graft‐poly (oxyethylene) and application as a polymeric surfactant in emulsion polymerization
Authors: Piirma Irja , Lenzotti James R.
Published: April 2007

Poly(p‐methylstyrene)‐graft‐poly(oxyethylene) copolymers were prepared from p‐methylstyrene and æ‐hydroxy‐ω‐methyl‐poly(oxyethylene) using a ‘grafting on to’ technique. A total of 10 copolymers were synthesized varying in the hydrophobic back bone chain lengths, hydrophilic branch lengths and frequency of branches. The stabilizing efficiency of these amphipathic copolymers was studied in the emulsion polymerization of styrene. Using the number, size and size distribution of the particles as the criterion of stability, it was found that the polyoxyethylene (PEO) chain length is not as crucial for stability as the availability of the backbone for anchoring. A change in the backbone chain length (from M̄n = 1000 to 24000) with the same percent PEO had no effect on the outcome of the reaction: the latices stabilized to the same number of particles of the same size.
Polymerization of N‐vinylcarbazole initiated by UV‐radiation
Authors: Usanmaz Ali , Onal Ahmet M. , Bostan Serap
Published: April 2007

The solid‐state polymerization of N‐vinylcarbazole initiated by UV‐radiation at 25, 32.5, and 45°C was studied. The rate of polymerization increased with increase in temperature. The limiting conversion at all temperatures is 56%. The molecular weight, determined by viscosity measurements, first increased, reached a maximum, then decreased. The molecular weight distribution, studied by GPC, was broad with a shoulder on the low molecular weight side. The morphology of partially polymerized single crystals was studied by electron scanning microscopy to determine the propagation mode of polymerization with respect to the monomer structure. The high activation energy of 71‐9kJ/mol and ESR spectrum suggest a radical mechanism of polymerization.
Formation of polymer‐polymer complexes and blends in the system poly(acrylic acid)‐poly(vinyl methyl ether)
Authors: Cowie John M. G. , Garay M. Teresa , Lath Dieter , McEwen Lain J.
Published: April 2007

The formation of a 1:1 polymer‐polymer complex from poly(acrylic acid) and poly(vinyl methyl ether) has been detected by viscosity measurements in aqueous solution, and the glass transition temperature of the isolated complex has been determined. Infrared spectroscopy indicates that specific hydrogen bonding occurs between the components of the complex. Miscible blends of the two polymers can also be formed (at all compositions) and, although hydrogen bonding occurs, the structures of the blends are likely to be dissimilar to that of the complex.
Reactive microgels—polymers intermediate in size between single molecules and particles
Authors: Funke Werner
Published: April 2007

Reactive microgels are considered as soluble intramolecular cross‐linked macromolecules, with sizes comparable to linear or branched macromolecules and reactive groups at their surface or interior. This article is the written version of a Macrolux 1988 lecture. It presents the history and some more important results and relationship of synthesis, characterization and properties of this group of polymers and refers briefly to application.