bluuebunny/crossref_metadata_2025 huggingface dataset:
Local institutionalization, discontinuity, and German textbooks of psychology, 1816–1854
Authors: Teo Thomas
Published: April 2007

In the context of social and intellectual developments and the changing role of German universities in the first half of the nineteenth century, which led to the local institutionalization of the discipline of psychology at German universities, the structure and content of textbooks of psychology are discussed. Textbooks in the first half of the nineteenth century had a pedagogical function in training teachers, in socializing students into the field, and in providing students and readers with knowledge about the subject matter, methodology, and topics of psychology. The textbooks, representative of influence, philosophical‐psychological orientations, and different decades in the first half of the nineteenth century, are reconstructed with regard to the definition of psychology, the ways of studying the soul, and how to conceptually organize the field. The textbooks by Herbart, Beneke, and Waitz, which were written within a natural‐scientific programmatic vision for psychology, are contrasted with the traditional philosophically intended textbooks of Reinhold, Mußmann, George, and Schilling. Fischhaber's textbook forGymnasienis summarized. Issues regarding the continuity of psychology are discussed, and discontinuous developments in the history of German psychology are identified. © 2007 Wiley Periodicals, Inc.
Stress‐ulcer prophylaxis for general medical patients: A review of the evidence
Authors: Janicki Todd , Stewart Scott
Published: April 2007

BACKGROUND

Gastric stress ulceration and bleeding are common occurrences in the critically ill and prophylactic acid‐suppression is used almost universally in this population. Evidence suggests that general medical patients hospitalized outside of the intensive care unit often receive similar therapy.

PURPOSE

To determine how frequently general medical patients are prescribed stress ulcer prophylaxis and what evidence exists for doing so.

DATA SOURCE

The MEDLINE database (1966 to October 2005), the Cochrane Central Register of Controlled Trials (4th Quarter 2005), and the bibliographies of selected articles.

STUDY SELECTION

Studies that contained significant data about either the frequency of use of stress ulcer prophylaxis in general medical patients or gastrointestinal bleeding outcomes in patients given prophylaxis.

DATA EXTRACTION

The primary author extracted prevalence and outcome data.

DATA SYNTHESIS

Descriptive studies suggest that 20–25% of general medical patients receive acid suppression for stress ulcer prophylaxis in the absence of presumed (but not established) risk factors for bleeding. Only two randomized, controlled trials evaluated the effects of prophylaxis in this population. The first found a reduction in clinically significant gastrointestinal bleeding from 6% (3 of 48) with placebo to zero (n = 52) with magaldrate. The second found a reduction in clinically significant bleeding from 3% (2 of 70) with sucralfate to zero (n = 74) with cimetidine.

CONCLUSION

A significant number of general medical patients are prescribed acid‐suppressive therapy for stress ulcer prophylaxis. The literature provides only sparse guidance on this issue with two randomized trials showing a possible benefit for prophylaxis. Further study is needed. Journal of Hospital Medicine 2007;2:86–92. © 2007 Society of Hospital Medicine.
Expanding the roles of hospitalist physicians to include public health
Authors: Kisuule Flora , Minter‐Jordan Myechia , Zenilman Jonathan , Wright Scott M.
Published: April 2007

Several years after the inception of the hospitalist movement, hospitalist roles have evolved in breadth and sophistication. Although public health is not formally recognized or previously described as an arena for hospitalists, hospitalists are often engaged in public health practice. This article attempts to alert hospitalists to the potential to make contributions to the field of public health and defines the public health skills that can positively affect the lives of their patients and the communities they serve. In a public health role, hospitalists may improve the quality of inpatient care. This article reviews how public health and hospital‐based practices have already intersected and proposes further development within this discipline. In our ever‐changing health care system, hospitalists play key roles in the central public health domains of assessment, assurance, and policy development. Insightful hospitalists will recognize and embrace these responsibilities in caring for patients and society. Journal of Hospital Medicine 2007;2:93–101. © 2007 Society of Hospital Medicine.
Relationship between cartilage stiffness and dGEMRIC index: Correlation and prediction
Authors: Baldassarri Marta , Goodwin Jesse S. Little , Farley Michelle L. , Bierbaum Benjamin E. , Goldring Steven R. , Goldring Mary B. , Burstein Deborah , Gray Martha L.
Published: April 2007

We sought to determine if a generalized relationship between the dGEMRIC index (T1Gd relaxation time) and compressive stiffness of articular cartilage could be defined across multiple samples. Osteochondral blocks were cut from 12 human tibial plateaus, six from cadaveric sources and six from total knee replacement surgeries. Each block contained submeniscal (“covered”) and extrameniscal (“uncovered”) cartilage regions. At ∼18 sites per block, a pulse indentation was applied and local dGEMRIC index was determined using dGEMRIC MRI. No correlation was found between stiffness and full cartilage depth dGEMRIC index. When averaged over the depth comparable to the indentation, good correlations were found between stiffness and the dGEMRIC index whether all data were combined, or whether each sample/region was considered independently. However, the standard error of the estimate for predicting stiffness from the local dGEMRIC index was improved when the uncovered and covered regions were considered separately. Further improvement in predictive capacity was obtained if, rather than predict absolute stiffness, differences in the dGEMRIC index across a region were used to predict difference in stiffness. The dGEMRIC index is highly correlated to mechanical stiffness. A generalized relationship was found to provide good correspondence across sources and regions. Use of the dGEMRIC index as a predictive measure of stiffness is possible, depending on the application's acceptable error. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:904–912, 2007
Sourdough fermentation of wheat fractions rich in fibres before their use in processed food
Authors: Lioger Delphine , Leenhardt Fanny , Demigne Christian , Remesy Christian
Published: April 2007

Fibre‐rich fractions of wheat are an important source of minerals but also contain considerable amounts of phytic acid, known to impair mineral absorption. This study explores the efficiency of wheat bran sourdough fermentation on phytate hydrolysis and mineral solubility, in comparison with whole‐wheat flour. In vitro trials were performed to assess the consequences of the addition of calcium carbonate (CaCO3), an alkalinising salt, on phytic acid breakdown and mineral bioavailability during sourdough fermentation. Sourdough fermentation was found effective for solubilising minerals in whole‐wheat flours but was less effective with bran. In addition, sourdough acidity was blunted by the addition of CaCO3, whereas degradation of phytic acid remained effective. Despite extensive breakdown of phytic acid (almost 70%), the addition of calcium exerted a very negative effect on zinc solubility. In conclusion, a pre‐fermentation process of whole cereals or bran, in suitable conditions of hydration, allows degradation of the major part of phytic acid and optimal mineral bioavailability. Copyright © 2007 Society of Chemical Industry
Purification and characterization of a cationic peroxidase from artichoke leaves
Authors: Cardinali Angela , Sergio Lucrezia , Di Venere Donato , Linsalata Vito , Fortunato Donatella , Conti Amedeo , Lattanzio Vincenzo
Published: April 2007

Peroxidases are part of a large group of enzymes associated with cell wall biosynthesis, response to injury, disease, resistance and wound repair. Among peroxidase isoenzymes, a soluble cationic peroxidase (ALSP), not yet described, has been partially purified and characterized from artichoke leaves. The enzyme was shown to be a glycoprotein with a molecular weight of 51 000 and an isoelectric point of 9. The substrate specificity of the ALSP is characteristic of class III (guaiacol‐type) peroxidases. The ALSP was partially purified by ammonium sulfate precipitation, gel filtration, affinity chromatography, anionic exchange high‐performance liquid chromatography and isoelectrofocusing. The increase in specific activity was 43 times compared to the crude extract as estimated by the guaiacol assay. Three ALSP fragments were sequenced by tandem mass spectrometry de novo sequencing method. Copyright © 2007 Society of Chemical Industry
Effects of head group size on the reaction methyl 4‐nitrobenzenesulfonate + Br− in water‐ethylene glycol cetyltrialkylammonium bromide micellar solutions
Authors: Rodríguez María Amalia , Muñoz María , Graciani María del Mar , Fernández Gaspar , Moyá María Luisa
Published: April 2007

The reaction methyl 4‐nitrobenzenesulfonate + Br− has been studied in water‐ethylene glycol cetyltrialkylammonium bromide (alkyl = methyl, ethyl, propyl, and butyl) micellar solutions by changing surfactant concentration as well as the weight percentage of ethylene glycol present in the bulk phase. The pseudophase model was adequate to rationalize quantitatively the micellar kinetic effects. Information about the influence of the head group size on the second‐order rate constant of the process and on the binding equilibrium constant of the organic substrate to the cationic micelles in water–ethylene glycol mixtures was obtained. Kinetic data taken from the literature were compared to those obtained in this work in order to examine the different effects produced by an alcohol that is localized in the bulk phase, such as ethylene glycol, with those caused by an alcohol that distributes between the bulk and micellar pseudophases, such as 1‐butanol. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 346–352, 2007
Kinetic model of olefin hydroalumination by HAlBui2 and AlBui3 in the presence of Cp2ZrCl2 catalyst
Authors: Parfenova Lyudmila V. , Balaev Alexandr V. , Gubaidullin Irek M. , Abzalilova Liya R. , Pechatkina Svetlana V. , Khalilov Leonard M. , Spivak Semyon I. , Dzhemilev Usein M.
Published: April 2007

The mechanism of α‐olefin hydroalumination by HAlBui2, ClAlBui2, and AlBui3 in the presence of Cp2ZrCl2 catalyst has been studied. It was established that the key intermediate of the reaction is a bimetallic complex [Cp2ZrH2 · ClAlBui2]2, which reacts with olefins and yields higher diisobutylalkylalanes. In parallel with this stage, the key complex can readily react with XAlBui2 (X = H, Cl, Bui) and form a stable trihydride complex Cp2ZrH2 · ClAlBui2 · HAlBui2, which does not exhibit reactivity in olefin hydroalumination. A kinetic model of α‐olefin hydroalumination with HAlBui2 and AlBui3 has been developed. The model explains the causes of the low stability of the key intermediate [Cp2ZrH2 · ClAlBui2]2 and of the different activities of organoaluminum compounds (OACs) in the olefin hydroalumination reaction. Moreover, the model gives information about the limit stages of the reaction and explains the influence of the length of the initial olefins on the rate of the whole catalytic process. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 333–339, 2007
Linear free‐energy relationships in chromium(VI) oxidation of substituted benzylamines in nonaqueous media
Authors: Thirumoorthi A. , Bhuvaneshwari D. S. , Elango K. P.
Published: April 2007

The kinetics of oxidation of 11 para‐ and meta‐substituted benzylamines by imidazolium fluorochromate (IFC) in different organic solvent media has been investigated in the presence of p‐toluenesulfonic acid (TsOH). The reaction was run under pseudo‐first‐order conditions. The rate of the reaction was found to be first order in IFC and found to increase with increase in [TsOH]. Solution IR studies in combination with kinetic measurements were used to get a better insight into the mechanism of the oxidation process. The product analysis was carried out using GC–MS. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of the isokinetic relationship. The specific rate of oxidizing species benzylamines reaction (k2) correlates with Hammett's substituent constants affording positive reaction constants. The rate data failed to correlate with macroscopic solvent parameters, such as εr and ENT, while showing satisfactory correlation with Kamlet–Taft's solvatochromic parameters (α, β, and π*) which suggests that the specific solute–solvent interactions play a major role in governing the reactivity, and the observed solvent effects have been explained on the basis of solute–solvent complexation. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 362–369, 2007
Early and Late Outcome of Cardiac Surgery in Patients with Liver Cirrhosis
Authors: Filsoufi Farzan , Salzberg Sacha P. , Rahmanian Parwis B. , Schiano Thomas D. , Elsiesy Hussien , Squire Anthony , Adams David H.
Published: April 2007

Liver cirrhosis is a major risk factor in general surgery. Few studies have reported on the outcome of cardiac surgery in these patients. Herein we report our recent experience in this high-risk patient population according to the Child-Turcotte-Pugh classification and Model for End-Stage Liver Disease (MELD) score. Between January 1998 and December 2004, 27 patients (mean age 58 ± 10 yr, 20 male) with cirrhosis who underwent cardiac surgery were identified. Patients were in Child-Turcotte-Pugh class A (n = 10), B (n = 11), and C (n = 6) and mean MELD score was 14.2 ± 4.2. Operative mortality was 26% (n = 7). Stratified mortality according to Child-Turcotte-Pugh class was 11%, 18%, and 67% for class A, B, and C, respectively. No mortality occurred in patients who had revascularization without the use of cardiopulmonary bypass (n = 5). The 1-yr survival was 80%, 45%, and 16% for Child-Turcotte-Pugh class A, B, and C, respectively (P = 0.02). Major postoperative complications occurred in 22%, 56%, and 100% for Child-Turcotte-Pugh class A, B, and C, respectively. Child-Turcotte-Pugh classification was a better predictor of hospital mortality (P = 0.02) compared to MELD score (P = 0.065). In conclusion, our results suggest that cardiac surgery can be performed safely in patients with Child-Turcotte-Pugh class A and selected patients with class B. Operative mortality remains high in class C patients. Careful patient selection is critical in order to improve surgical outcome in patients with cirrhosis. Liver Transpl, 2007. © 2007 AASLD.
Fast frequency response computation for Rayleigh damping
Authors: Meerbergen K.
Published: April 2007

We present a model reduction Lanczos method for the computation of frequency response functions of Rayleigh damping problems. The connection with modal extraction and modal superposition is made. The usual model reduction methods require complex arithmetic. With the proposed method, complex arithmetic is only used for the reduced problem. A numerical example from structural damping is given. Copyright © 2007 John Wiley & Sons, Ltd.
Targeted RNA interference of phosphatidylinositol 3‐kinase p110‐β induces apoptosis and proliferation arrest in endometrial carcinoma cells
Authors: An HJ , Cho NH , Yang HS , Kwak KB , Kim NK , Oh DY , Lee SW , Kim HO , Koh JJ
Published: April 2007

Phosphatidylinositol 3‐kinase (PI3K) signalling plays a pivotal role in intracellular signal transduction pathways involved in cell growth, cellular transformation, and tumourigenesis. PI3K is overexpressed in many human cancers, including endometrial carcinomas, one of the most common female genital tract malignancies. Here, we used small interfering RNA (siRNA) targeted to PI3K p110‐β to determine whether inhibition of the β isoform could be a potential therapeutic target for endometrial carcinoma. In this study, treatment of HEC‐1B endometrial cancer cells with PI3K p110‐β‐specific siRNA resulted in increased apoptosis and decreased tumour cell proliferation. Depletion of PI3K p110‐β decreased the protein levels of AKT1, AKT2, pAKT, and mTOR—downstream targets of PI3K. Knock‐down of PI3K p110‐β by siRNA also induced decreased expression of cyclin E and Bcl‐2, suggesting that PI3K p110‐β stimulates tumour growth, at least in part by regulating cyclin E and Bcl‐2. Thus, our results indicate that siRNA‐mediated gene silencing of PI3K p110‐β may be a useful therapeutic strategy for endometrial cancers overexpressing PI3K p110‐β. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Classifying the intensity of pediatric cancer treatment protocols: The intensity of treatment rating scale 2.0 (ITR‐2)
Authors: Werba Branlyn E. , Hobbie Wendy , Kazak Anne E. , Ittenbach Richard F. , Reilly Anne F. , Meadows Anna T.
Published: April 2007

Background

To develop and validate a method of classifying the intensity of pediatric oncology treatments using four operationally defined categories of treatment intensity.

Procedure

An earlier version of a rating scale, the intensity of treatment rating (ITR), was revised and validated in two phases. In the Scale Construction phase, three criterion raters revised the ITR items based on consensus and item agreement data from pediatric oncologist raters (N = 15). In the Scale Validation phase, the new ITR‐2 items were validated using a second set of pediatric oncologists external to our institution (N = 12). In addition, a third group of raters (N = 16), was employed to assess inter‐rater reliabilities for 12 patients at varying levels of treatment intensities.

Results

Agreement between criterion ratings and the median of external raters for all 34 items on the ITR‐2 was very high (r = 0.95, range 0.71–0.91). When the ITR‐2 was used to rate 12 patient examples, the inter‐rater agreement among pediatric oncologists was also very high (median agreement between criterion‐rater pairs: r = 0.87; overall relatedness among 16 raters: rICC = 0.83).

Conclusions

The revised ITR Scale 2.0 (ITR‐2) is a valid and reliable scale for classifying the intensity of pediatric oncology treatments. Pediatr Blood Cancer 2007;48:673–677. © 2007 Wiley‐Liss, Inc.
Laser light scattering studies of ternary polymer solutions
Authors: Daivis Peter J. , Pinder David N.
Published: April 2007

Ternary polymer solutions [polystyrene and poly(methylvinylether) dissolved in a single solvent] have been studied to investigate the thermodynamic compatibility of the polymers and the solvents, and also to facilitate the investigation of the self‐diffusion of polystyrene to greater polymer concentration. Both good and poor quality solvents have been used in this study. The self‐diffusion coefficient of the polystyrene has been measured by dynamic light scattering and by pulsed field gradient NMR where appropriate. The self‐diffusion data are also used to critically examine the recent theoretical developments in this field. Important confirmation of theory has been demonstrated for good solvent solutions and intriguing discrepancies have been discovered for poor solvent solutions.
The effects of processing on the mechanical properties of a polyolefin blend
Authors: Flaris Vicki , Stachurski Zbigniew H.
Published: April 2007

The procedure employed to prepare blends plays a significant role on the ultimate morphological and mechanical properties of the blend. This was demonstrated through the use of a styrene‐ethylene/butylene‐styrene (SEBS) triblock copolymer as a compatibilizer for isotactic polypropylene and linear lowdensity polyethylene. The considerable increases in impact strength for the blends containing the higher percentages of SEBS are related to the magnitude of plastic deformation observed in the matrix and to the size of the occlusions.
Synthesis and characterization of hydroxy‐terminated poly(alkylene oxides) by condensation polymerization of diols
Authors: Gunatillake Pathiraja A. , Meijs Gordon F. , Chatelier Ronald C. , McIntosh Donna M. , Rizzardo Ezio
Published: April 2007

Acid‐catalysed condensation polymerization of 1,6‐hexanediol, 1,8‐octanediol and 1,10‐decanediol was carried out in the 150–190°C temperature range in the presence of sulphuric acid or Nafion‐H resin, and the polymerizations were monitored by size‐exclusion chromatography. The products were identified as hydroxy‐terminated poly(alkylene oxides) by 1H and 13C NMR and IR spectroscopy. The polymers were obtained in 66–81% yield from both catalysts in the polymerizations of 1,8‐octanediol and 1,10‐decanediol. With 1,6‐hexanediol the polymer yields were 30 and 42‐56% in the presence of Nafion and sulphuric acid, respectively. These low yields were due to the formation of oxepane as confirmed by gas chromatographic analysis of volatile condensation products. Vapour pressure osmometry showed the number‐average molecular weight of polymers to be in the range 700‐2400, depending on the reaction time and temperature. The hydroxy functionality of the poly(alkylene oxides) was 2.0 as determined by vapour pressure osmometry and 1H NMR spectroscopy.
Synthesis of sulfoxide‐modified ethylene—vinyl alcohol copolymers for the permselective membrane of sulfur dioxide
Authors: Imai Kiyokazu , Shiomi Tomoo , Tezuka Yasuyuki , Inokami Kiyotaka
Published: April 2007

The Michael‐type addition reaction of ethylene‐vinyl alcohol copolymer (EVAL) with a series of vinyl sulfoxides namely methyl, ethyl, t‐butyl and phenyl vinyl sulfoxides, was performed with NaOH as a catalyst in DMSO solution to produce 2‐(alkyl or phenyl sulfinyl)ethyl EVAL derivatives. The high perm‐selectivity of sulfur dioxide against nitrogen was achieved through these sulfoxide‐modified EVAL membranes.
Terpolymerization reactions of N‐acryloyloxyphthalimide or N‐methacryloyloxyphthalimide with methyl acrylate, methyl methacrylate and acrylonitrile
Authors: Mahmoud A. A. , Shaaban A. F. , Khalil A. A. , Messiha N. N.
Published: April 2007

Ternary copolymerization reactions of N‐acryloyloxyphthalimide (NAP) or N‐methacryloyloxyphthalimide (NMP) and acrylonitrile with methyl acrylate or methyl methacrylate were carried out in solution at 60°C in the presence of a free radical initiator. Experimental terpolymerization data agree well with calculations based on the Alfrey‐Goldfinger equation. The determination of unitary, binary, and ternary azeotropies of the various systems studied was easily handled by a computer program. The results show that there is no ternary azeotropic composition for any terpolymer system studied. Selective unitary and binary azeotropic compositions were polymerized and the results show good agreement between the theoretical and experimental terpolymer composition in each case. The estimation of terpolymer compositions was carried out by 1H NMR spectroscopy.
Experimental Criteria for Living Polymerizations
Authors: Quirk Roderic P. , Lee Bumjae
Published: April 2007

Seven experimental criteria for living polymerizations are critically reviewed. The limitations of the use of linear plots of M̄n (or X̄;n) versus conversion and linear plots of the number of polymer chains versus conversion are illustrated by an example of alkyllithium‐initiated polymerization of styrene by incremental additions of styrene with deliberate termination (5% per incremental monomer addition). The experimental criteria of using narrow molecular weight distribution and the formation of block copolymers are illustrated with practical examples and size exclusion chromatography data. The use of the terms ‘living polymerization with reversible termination’ and ‘living polymerization with reversible chain transfer’ are proposed.
The surface energy spectrum of PVC
Authors: Mash C. J.
Published: April 2007

A new theory enabling the surface energy of a solid to be expressed as a quantitative energy spectrum has recently been proposed. This theory was tested on clean and contaminated polyvinyl chloride (PVC) surfaces which yielded remarkably different spectra. Electron spectroscopy for chemical analysis (ESCA) confirmed that peak energies could be correlated with specific molecular groups exposed at the surface.
Control of polymerization processes of 10,12‐pentacosadiynoic acid LB films
Authors: Ogawa Kazufumi
Published: April 2007

Studies have been carried out on KrF excimer laser light (EX), X‐ray or electron beam (EB) induced polymerization of 10,12‐pentacosadiynoic acid (PDA) Langmuir‐Blodgett (LB) films in relation to molecular density or molecular arrangement of the films using X‐ray diffraction analysis, infrared (IR) spectroscopy and Raman spectroscopy. The molecular arrangement or density of the PDA LB films was controlled by subphase conditions when the films were built up, such as pH, temperature of a subphase or salt concentration in the subphase. Polymerization sensitivity of the PDA LB film was affected by the arrangement or molecular density. On low density (A type) films the polymerization occurred by irradiation with EX, X‐ray or EB, but on high density (B type) films the polymerization occurred only when the irradiation was carried out by high energy beams such as X‐ray or EB. Decomposition of polymerized films was observed further by excessive irradiation of EX or X‐ray, but not on the B type films. It was revealed by X‐ray diffraction analysis that in the A type film, the PDA molecules bent to a larger extent than those in the B type film and the polymerization proceeded topochemically, that is, the thickness decreased little after EB irradiation in a helium atmosphere. On the other hand, in the B type film, the thickness decreased by about 10% as a result of EB irradiation. By IR reflection‐absorption (RA) and Raman measurements, it was confirmed that conjugated diacetylenic bonds disappeared and conjugated double and new conjugated triple bonds appeared after high energy beam irradiations. These results support the supposition that 1,4‐polymerization, i.e. polydiacetylene type polymerization, occurs easily in the A type film and 1,2‐ or 3,4‐polymerization, i.e. polyacetylene type polymerization, occurs in the B type film, and that the polymerized A type film was decomposed at the polydiacetylenic bond when the irradiation continued further. It was also shown that the polyacetylene type polymer was obtained only when the B type film was irradiated with the high energy beam.
Organic and polymer planar optical waveguides
Authors: Zheng Shu , Simon George P. , Binh Le N.
Published: April 2007

Single‐mode and multi‐mode planar optical waveguides with low loss were fabricated by spin‐coating thin films of poly(vinyl alcohol) (PVAl) and 4‐dihexylamino‐4′‐nitro‐stilbene (DHANS) doped poly(methylmethacrylate) (PMMA) onto glass substrates, and characterised by theoretical analysis and optical guided‐mode measurements. The optical constants of the waveguides were determined with good accuracy by measuring the coupling synchronised angles and fitting them, via a recursion method, into the waveguide dispersion equations. The number of the guided modes observed in these thin films can be controlled by tailoring the film thickness.
Syntheses and investigations of copolymers for improving the flow of middle distillate oils
Authors: Alan Holder G. , Macauley David
Published: April 2007

The results of a review of the patent literature on polymeric flow improvers for distillate fuels showed that a diverse range of polymeric compositions is effective. Ethylene‐containing compositions predominate and of these ethylene‐vinyl acetate (EVA) copolymers are the most common. Ethylene‐vinyl acetate copolymers were synthesised using a high pressure autoclave. The effectiveness of the copolymers varied greatly with the chemical composition of the copolymer. The techniques described in the literature for the determination of the composition of EVA copolymers are summarised and reviewed. A new technique using proton nuclear magnetic resonance was developed. A statistical analysis of the results is presented.
Mesomorphic polyblends of poly(p‐phenylene terephthalamide) and poly(4,4′‐terephthanilide adipamide)
Authors: Son Tae Won , Kim Byoung Chul
Published: April 2007

A simultaneous dissolution of two lyotropic polyamides, poly(p‐phenylene terephthalamide) (PPTA) and poly(4,4′‐terephthanilidc adipamide) (PTAd), in a concentrated H2SO4 (1 to 1.5% wt) produced an isotropic single phase solution. The crystallinity of PPTA/PTAd blends confirmed formation of a mesomorphic polyblend to the molecular level. With increasing concentration, solutions of these PPTA/PTAd blends in 100% H2SO4 showed a sequential phase change typical of a single lyotropic polymer. Further, the ternary solution exhibited a wider biphase range than both binary solutions of PPTA/100% H2SO4 and PTAd/100% H2SO4. Dry‐jet wet spinning of anisetropic solution of this ternary composition with a PTAd weight fraction less than 0.5 enabled us to obtain PPTA/PTAd blend fibers. Including a PTAd weight fraction of 0.1‐0.15 reduced both the orientation angle and fibrillation. The particular blend fiber with a PTAd weight fraction of 0.15 exhibited a synergistic effect on the mechanical properties.
Viscoelastic behaviour in the molten state of low density polyethylene‐polybutene 1 blends
Authors: Deri F. , Behar O.
Published: April 2007

The viscoelastic behaviour in the molten state of low density polyethylene‐polybutene 1 blends has been studied according to temperature, shearing stress and shearing rate. Measurements were made with a capillary viscometer for the static properties and a balance‐rheometer system of Kepes for the dynamic properties. Correction of experimental data has been performed and flow activation energies at a constant shear stress determined, whilst elasticity was investigated by means of the Barus factor. Furthermore, an investigation has been performed on variations of the real η′ and imaginary η″ parts of the complex viscosity with regard to the pulsation frequency ω. The Cole‐Cole and the Smyth representations were utilised to determine the Newtonian viscosity ηo, the parameter of distribution of relaxation time h and the average relaxation time ηo.
Solid state NMR detection of molecular mixing in bieutectic blends, d‐metal complexes, and phase‐separated copolymers
Authors: Belfiore Laurence A. , Graham Hugh , Veda Eiji , Wang Yinghua
Published: April 2007

This research contribution addresses micromixing in polymer blends that exhibit strong intermolecular association. Specific interactions between dissimilar blend components are detected via high‐resolution solid state proton and carbon‐13 NMR spectroscopy. The isotropic chemical shifts of the critical component provide strong evidence that molecular complexes form. NMR spectral differences between the blends versus the undiluted components arise from crystal structure modifications (if appropriate), conformational changes, hydrogen bonding, d‐metal coordination, or altered packing geometries that occur concomitantly with the mixing process. More convincing evidence that two components of a strongly interacting blend reside in a near‐neighbor environment is obtained from the measurement of proton spin diffusion between dissimilar species. Proton spin diffusion is measured directly via the high‐resolution CRAMPS experiment (Combined Rotation And Multiple Pulse Spectroscopy) in a homogeneous solid solution of poly(ethylene oxide) and resorcinol, and indirectly via the carbon‐13 spin system in a modified version of the Goldman‐Shen experiment for microphase‐separated ionic and tri‐block copolymers. One of the primary objectives of this research endeavor is to bridge the gap between macroscopic and site‐specific probes of phase behavior and strong interaction in mixtures that form homogeneous solid solutions or coordination complexes. In this respect, results from a macroscopic phase of the polymer‐blend research are included in this contribution. Thermal and mechanical properties are measured for strongly interacting systems, whose interaction sites are characterized via solid state NMR. Metal‐ligand coordination in blends of nickel acetate with poly(4‐vinylpyridine) produces an extraordinary synergistic effect on the glass transition response. The maximum increase in blend Tg relative to the undiluted polymer is in the order of 100°C. Coordination between the nitrogen lone pair in poly(4‐vinylpyridine) and the zinc cation in DuPont's SURLYNTM ionomers produces a 15% enhancement in mechanical fracture stress relative to the undiluted ionomer. The success of our structure‐property relationship scheme described herein, which bridges microscopic detection of site‐specific interactions (via NMR) with practical macroscopic (DSC and stress‐strain) measurements, depends upon our ability to understand material properties at a level where continuum hypotheses are no longer valid.
Temperature transitions and compatibility in gradient interpenetrating polymer networks
Authors: Lipatov Yu. S. , Karabanova L. V. , Gorbach L. A. , Lutsyk E. D. , Sergeeva L. M.
Published: April 2007

Traditional and gradient IPNs of various composition have been prepared from cross‐linked polyurethane and poly(butyl methacrylate). For various layers of gradient IPN cut from the surface to the centre the glass transition temperatures and composition have been determined. The sorption of benzene vapour by various layers was measured, and from these data the free energy of mixing IPN components has been calculated.

For all the layer compositions free energies of mixing are positive and dependent on the distance from the sample centre. This effect is thought to be connected not only with composition but with various conditions for phase separation in various layers.

Each layer consists of two phases with their own glass transition temperatures. From these data, using the Fox equation, the composition of each phase for various layers have been calculated and the volume ratio of phase evolved was estimated.
Synthesis and characterization of polyimides and polyamide‐imides containing azomethine linkages
Authors: Idage Susheela B. , Idage Bhaskar B. , Vernekar Subhash P.
Published: April 2007

Polyimides and polyamide‐imides containing azomethine linkages in the polymer backbone have been synthesized from 4,4′‐bis(4‐isocyanatobenzylidene)‐diaminodiphenylether (ODAI), 4,4′‐bis(4‐isocyanatobenzylidene)‐diaminodiphenyl‐methane (MADI), 4,4′‐bis(4‐isocyanatobenzylidene)‐diaminodiphenylsulphone (SDAI), pyromellitic dianhydride (PMDA), 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA), and trimellitic anhydride (TMA), by a one‐step process. The diisocyanates ODAI, MDAI and SDAI were prepared from the corresponding diacids, namely, 4,4′‐bis(4‐carboxybenzylidene)‐diaminodiphenylether (ODAA), 4,4′‐bis(4‐carboxybenzylidene)‐diaminodiphenylmethane (MDAA) and 4,4′‐bis‐(4‐carboxybenzylidene)‐diaminodiphenylsulphone (SDAA) by a Weinstock‐modified Curtius rearrangement method. All the polycondensation reactions were conducted in N‐methyl‐2‐pyrrolidone (NMP) under identical conditions and the polymers obtained were characterized by IR spectroscopy, solution viscosity, elemental analysis, thermogravimetric analysis, differential scanning calorimetry and X‐ray diffraction.
Non‐steady‐state model for kinetics of free radical polymerization, 3. Direct photo‐initiation
Authors: Lin Jianming , Yan Deyue , Yuan Cuiming
Published: April 2007

The non‐steady‐state kinetics of directly photo‐initiated polymerization were studied theoretically. Taking account of the facts that the amount of monomer consumed in propagation is much more than that in initiation for a process producing high polymer and that the rate constant of chain termination is much larger than that of chain propagation or transfer, a few very close approximations were adopted to solve the set of kinetic differential equations of the polymerization under consideration. The inexplicit function method developed in a previous paper of this series for the derivation of the molecular weight distribution function is still valid in this work. Some numerical computation was implemented to show the tendency of free radical concentration decay and the plots of molecular size distribution.
The effect of the vinyl acetate content and distribution in poly(vinyl alcohol/vinyl acetate) copolymers upon their electronic absorption spectra in aqueous and electrolyte solutions
Authors: Eagland Donald , Crowther Nicholas J. , Donners Wim A. B. , Vercauteren Frank F.
Published: April 2007

Absorbance measurements over a temperature range of 1‐35°C, at wavelengths of 205 and 262 nm, are presented for a series of aqueous and electrolyte solutions of poly(vinyl alcohol/vinyl acetate) copolymers, of varying acetate group content and distribution. The results reflect the effect of both the nature of the solvent and the microarchitecture of the macromolecule in dictating the conformation of the polymer and hence the degree of exposure of the carbonyl moiety of the acetate group to the solvent.
Aqueous polyurethane dispersions: Effects of dmpa and bisphenol a polyol on dispersion and physical properties of emulsion cast films
Authors: Lee Young Min , Kim Tae Kyoon , Kim Byung Kyu
Published: April 2007

Aqueous dispersions of polyurethane (PU) ionomers were prepared from hydrogenated diphenylmethane diisocyanate (H12MDI), poly(tetramethylene adipate) glycol (PTAd), bisphenol A propylene oxide ether glycol (LER), and dimethylol propionic acid (DMPA) as potential ionic centres. The urethaneforming reaction was carried out in N‐methyl‐2‐pyrrolidone (NMP) with dibutyltin dilaurate (DBT) as catalyst. The effects of DMPA and bisphenol A polyol on the particle size of the dispersions, and the physical properties of the emulsion cast films were determined. It was found that the particle size decreased with DMPA, and increased with bisphenol A polyol contents. Initial modulus and tensile strength of the emulsion cast films increased, and the elongation at break decreased with DMPA and bisphenol A polyol contents. The results were interpreted in terms of increased interchain Coulombic forces and urethane linkages with DMPA, and increased chain rigidity of PU with bisphenol A polyol incorporation.
Synthesis and biological activity of polyketones
Authors: Patel N. Z. , Patel J. N. , Patel R. M. , Ray R. M.
Published: April 2007

Polyketones have been prepared by reacting benzene, chloroacetyl chloride, 1,2‐dichloroethane and dichloromethane using anhydrous aluminium chloride as catalyst and nitrobenzene as solvent. Polyketones were characterized by IR which showed the presence of carbonyl and chlorine groups in the resins. Thermal analysis showed the remarkable thermal stability of the resins. All the polyketones were tested for their biological activity against P.fluorescens, B. subtilis, A. niger and T. viride. The results show that most of the polyketones can be used as antibacterial and antifungal agents.
Polymerization of monomer films of triazine dithiols on a copper surface
Authors: Mori Kunio , Oishi Yoshiyuki , Miyashita Tokuji , Matsuda Minoru
Published: April 2007

On heating films of long‐chain alkylamino‐1,3,5‐triazine‐2,4‐dithiols, substituted with unsaturated groups in the 6‐position, on copper plates in air, the films become partially insoluble in benzene. The polymerization rate and monomer conversion increased with temperature above 80°C and with time. At low temperatures, an induction period was observed. The detailed behavior was dependent upon the number and length of the alkyl chains. Films with high packing density polymerized more slowly. In the presence of azobis(isobutyro)nitrile (AIBN) and benzoyl peroxide (BPO), the rate and conversion increased and the induction period disappeared. The optimum concentration of initiators was approximately 0.0025 mol% of monomer. The polymerization of the films was initiated by oxygen activated with copper, or by radicals derived from AIBN and BPO. It is proposed that the growth of polymer proceeded mainly by the addition of thiyl radicals to unsaturated groups, the insoluble polymers being formed by the coupling of thiyl radicals.
N,N′‐methylene‐bis‐acrylamide‐crosslinked polyacrylamides as supports for dithiocarbamate ligands for metal ion complexation
Authors: Mathew Beena , Rajasekharan Pillai V. N.
Published: April 2007

The complexation behaviour of dithiocarbamate functions supported on polyacrylamides with varying extents (2‐20 mol%) of N,N′‐methylene‐bis‐acrylamide (NNMBA) crosslinks was investigated. The crosslinked polyacrylamides were prepared by the free radical solution polymerization of the monomers in water at 80°C using potassium persulphate as initiator. The dithiocarbamate ligands were introduced by polymer‐analogous reaction involving transamidation with ethylenediamine and dithiocarbamylation with carbon disulphide and alkali. The complexation behaviour of these dithiocarbamate resins with the ligand functions in different macromolecular environments were investigated towards Co(II), Ni(II), Cu(II), Zn(II) and Hg(II) ions by a batch equilibration technique. The metal ion intake varied with the extent of the NNMBA‐crosslinking. Thus the 8% crosslinked system has the highest complexation capacity. The values for metal ion intake followed the order Hg(II)> Cu(II)> Zn(II)> Ni(II)> Co(II). The time‐course of complexation, the possibility of recycling and the swelling characteristics of the uncomplexed and complexed resins were considered, and IR characterization and thermal studies were undertaken. The swelling values of the complexed resins are lower than those of the uncomplexed resins. The thermal stability of dithiocarbamates varied with the extent of NNMBA‐crosslinks and with the metal ion.
Ageing effects on mechanical properties of gutta‐percha (trans‐polyisoprene)
Authors: Arvanitoyannis Ioannis , Blanshard John M. V. , Kolokuris Ioanniis
Published: April 2007

This study examined both the effect of chemical composition and of storage (ageing), for periods up to 28 weeks, and at temperatures from ‐ 15 to 50°C on the mechanical properties.

The presence of high contents of barium sulphate, zinc oxide and colouring agent in commercial dental gutta‐percha has the same effect on the mechanical properties of gutta‐percha as prolonged storage time, i.e. increase in brittleness. On the contrary, the presence of Thermoplast or Wax (75%) has an accentuated plasticising effect on gutta‐percha improving thus, to a certain extent, its clinical characteristics.
Dielectric relaxations in poly [2,2‐propane‐bis‐(4‐phenyl thiocarbonate)]
Authors: Sanchez Martínez E. , Díaz‐Calleja R. , Montserrat Ribas S. , Gargallo L. , Radić D.
Published: April 2007

The dielectric relaxation properties of poly[2,2‐propane‐bis‐(4‐phenyl thiocarbonate)] (PTC) have been studied. The existence of crystallinity, which can be eliminated by quenching, is detected. The degree of crystallinity of polymer samples was determined by differential scanning calorimetry in order to investigate the effect of this factor on the dielectric behaviour of this polymer. The thermal degradation of the samples was studied by thermogravimetry. The degradation of the polymer begins before the glass transition temperature Tg. The dielectric spectrum is complex showing several relaxation phenomena. With increasing temperature a γ relaxation can be observed at ‐ 100°C (5 kHz). The activation energy obtained from an Arrhenius plot (lnfvs T−1) is 6 kcal mol−1. At 160°C the α relaxation which is associated with the glass transition temperature Tg is detected. The dielectric behaviour of this poly(thiocarbonate) is compared with the corresponding poly(carbonate).
Radiation degradation of statistical terpolymers of two aromatic diols with diphenyl sulphone
Authors: Hill David J. T. , Lewis David A. , O'donnell James H. , Pomery Peter J. , Hedrick James L. , McGrath James E.
Published: April 2007

The variation in radiation resistance with composition of statistical terpolymers of (1) bisphenol‐A and biphenol, and (2) hydroquinone and biphenol, with diphenyl sulphone was studied by electron spin resonance spectroscopy after γ irradiation at 77 K and by analysing volatile products after irradiation at 423 K. Approximately linear relationships were obtained between the radiation chemical yields for both radicals, G(R), and sulphur dioxide, G(SO2), and the mole fraction of biphenol units in the terpolymers. Substantially higher radiation resistance was shown by biphenol units compared with either bisphenol‐A or hydroquinone.
A study of polycarbonate‐liquid crystal polymer blends
Authors: Magagnini P. L. , Paci M. , La Mantia F. P. , Valenza A.
Published: April 2007

The morphology and the thermal and mechanical properties of blends of bisphenol‐A polycarbonate (PC) with a wholly aromatic liquid crystal copolyester‐amide (Vectra‐B of Hoechst‐Celanese) are discussed with reference to the conditions used for their preparation. The blends made by extrusion behave as mixtures of incompatible polymers: the dispersed liquid crystalline phase is more or less oriented in the extrusion direction and acts as a reinforcing filler for the PC matrix. The behaviour of the blends prepared in a batch mixer depends strongly on mixing time. A slight decrease in the mechanical properties (especially tensile strength and elongation) accompanies the morphological changes associated with a progressive improvement in the compatibility of the two polymers, which finally leads to an apparently homogeneous material after 45 min mixing at 290°C and 150 rpm. These effects are interpreted in terms of chemical interactions taking place between the two components of the blends.
Surface properties of carbons from poly(vinyl chloride)
Authors: Youssef A. M. , Abdel‐Bary E. M. , Dowidar A. M.
Published: April 2007

Non‐activated carbons were prepared by the thermal degradation of poly(vinyl chloride) (PVC) in air or nitrogen atmosphere in the temperature range 600‐1000°C. Carbon dioxide‐activated carbons from PVC were also obtained by gasification of non‐activated carbon from PVC at 900°C burn‐off (4‐50%).

Thermal degradation in air atmosphere gave high carbon yield because the oxygen of air increased crosslinking at lower temperature and chemisorbed on the carbon surface at high temperatures. Thermal degradation in air and gasification with carbon dioxide created carbon‐oxygen surface groups which increased the hydrophilicity of the carbon surface and consequently increased water adsorption capacity. Gasification with carbon dioxide to high burn‐off created new pores and widened already existing pores.
Flow stress of high density polyethylene and nylon 66 at high rates of strain
Authors: Ahmad S. H.
Published: April 2007

Measurement of the flow stress of high density polyethylene (HDPE) and nylon 66 at strain rates of 103 s−1 using a split Hopkinson pressure bar technique is discussed. The flow stress at a strain of 10% has been determined for both polymers at 20°C. The intrinsic errors involved in this technique are briefly reviewed. The results indicate that the flow stress of HDPE and nylon 66 were 50MPa and 150MPa, respectively, at strain rates of about 103s−1.