bluuebunny/crossref_metadata_2025_split huggingface dataset:
The solid‐state polymerization and physical properties of 2,4‐hexadiynylene bis(N‐ethylcarbamate), 1 crystal modifications and polymerization kinetics
Authors: Galiotis Costas , Young Robert J. , Ando David J. , Bloor David 
Published: April 2003

AbstractThree distinct crystal modifications of 2,4‐hexadiynylene bis(N‐ethylcarbamate), (1c) are isolated under different conditions. The conditions necessary for the growth of crystals of the different modifications are described and their melting and phase transitions determined by differential thermal analysis. X‐Ray diffraction studies yielded unit cell dimensions for some modifications of the monomer 1c as well as the polymer 2c, but full structural analyses were impossible to obtain. Molecular models of 1c with different conformations have been constructed and shown to be compatible with the observed cell dimensions and solid‐state reactivities. The thermal and radiation polymerization kinetics of the two reactive modifications of 1c were studied. Despite the fact that the thermal polymerization of modification I of 1c is not a single‐phase process, the kinetics are well described by the crystal‐strain model, this fit being clearly fortuitous. A more detailed study of the kinetics reveals a second‐order behaviour and a model for a two‐phase polymerization process is proposed.
Functional monomers and polymers, 105. Synthesis of poly(β‐alanine) from a new type of active amino acid ester
Authors: Kondo Koichi , Miwa Yoshiyuki , Takemoto Kiichi 
Published: April 2003

AbstractActive β‐alanine esters having dipeptide groups, which are capable of forming hydrogen bonds between the side chains, were prepared in the form of hydrogen chloride salts. The polycondensation of these salts was studied in non‐polar solvents, in the presence of triethylamine. In the case of the ester with β‐alanyl‐β‐alanine as dipeptide moiety, the polycondensation proceeded smoothly in chloroform solution. To explain the characteristic feature of the polycondensation, an ordered aggregation of the ester molecules is assumed to play an important role. The ester with glycylglycine as dipeptide moiety, however, did not undergo a polycondensation.
Polymers based on p‐aminophenol, 3. Synthesis of the simplest aromatic poly(imide‐ester) from p‐aminophenol derivatives
Authors: Kurita Keisuke , Matsuda Shoko 
Published: April 2003

AbstractThe pyrolytic behavior of N‐(4‐hydroxyphenyl)phthalimide‐4‐carboxylic acid (3) and its two ester derivatives 4 and 5 was studied with the intention to synthesize the simplest aromatic poly(imide‐ester). Self‐polycondensation of 3 at elevated temperatures was not successful, but a pyrolytic ester exchange reaction of monomers 4 and 5 led to the poly(imide‐ester) 1. Though the viscosity was not high, the polymer was confirmed to exhibit excellent thermooxidative stability.
Aliphatische azoverbindungen, 14. Eine kinetische analyse des thermischen zerfalls aliphatischer azonitrile
Authors: Barbe Werner , Rüchardt Christoph 
Published: April 2003

AbstractKetenimines 4 are known to be formed in a side equilibrium during the thermal decomposition of azonitrile initiators 1, as e.g. 2,2′‐azoisobutyronitrile (1a). The concentration of 4 was monitored by IR during the decomposition reaction of 1, and the final yield ratio of substituted succinonitrile 3 and nitrile 5 was determined by GC. Together with the rate constant k1 of 1, these data suffice for calculating k‐3, the rate of decomposition of 4, and k3/k2 the rate ratio of the two possible modes of dimerisation of α‐cyanoalkyl radicals 2.
Hydrolysis of phenyl esters catalyzed by alternating copolymers containing imidazolyl and carboxyl groups
Authors: Tanaka Jiro , Yamada Akira 
Published: April 2003

AbstractThe alternating copolymer, poly(N‐vinylimidazole‐co‐maleic acid) (4), and the random copolymer, poly(N‐vinylimidazole‐co‐acrylic acid) (5), with nearly the same ratio of carboxyl groups to imidazolyl groups, were found to catalyze the hydrolysis of 3‐acetoxy‐N‐trimethyl‐anilinium iodide (1), 4‐nitrophenyl acetate (2), and 4‐acetoxy‐3‐nitrobenzoic acid (3). For these esters, the catalytic activity of 4 at pH >9 was found to be in the following order: 3 > 2 > 1 that for 1 being a retarding one. Copolymer 5 shows a reverse catalytic activity of the order 1 > 2 > 3. The catalytic site of the alternating copolymer 4 is the free imidazolyl group, and the reaction rate is enhanced by the carboxylate anion, whereas the reaction rate in the presence of the random copolymer 5 is controlled predominantly by electrostatic interaction forces between the substrate and sequential carboxylate anions.
Association of two‐block copolymer polystyrene‐block‐poly(2‐vinylpyridine) in toluene
Authors: Sikora Antonín , Tuzar Zdeněk 
Published: April 2003

AbstractThe association of two‐block copolymers polystyrene‐block‐poly(2‐vinylpyridine) has been studied in toluene (a solvent selective for polystyrene) by osmometry, viscometry, and light scattering. Polystyrene‐block‐poly(2‐vinylpyridine) in toluene forms polymolecular micelles having a poly(2‐vinylpyridine) core and a polystyrene shell, and micellization conforms to the model of closed association. The phenomenon of so‐called anomalous micellization has been observed within a certain temperature interval where unusually large particles are formed.
Preliminary results on ethylene/propene copolymerization in the presence of Cp2Ti(CH3)2/Al(CH3)3/H2O
Authors: Busico Vincenzo , Mevo Lorenzo , Palumbo Giuseppe , Zambelli Adolfo , Tancredi Teodorico 
Published: April 2003

AbstractEthylene/propene copolymerizations were carried out in the presence of the catalyst system Cp2Ti(CH3)2/Al(CH3)3/H2O (Cp = cyclopentadienyl group), and the reactivity ratios r1, r2 were determined through the Fineman and Ross equation and via 13C NMR. A nearly alternating copolymer structure was pointed out. The yields as well as the molecular weights of the copolymers strongly decrease with increasing propene mole fraction in the copolymers.
Memory of a polymeric matrix, stabilizing the initial conformation of potassium bis[N‐(5‐methacryloylamino)‐salicylidene‐(S)‐norvalinato]‐cobaltate(III) in the deuterium exchange
Authors: Belokon Yuri N. , Tararov Vitali I. , Savel'eva Tatiana F. , Vorob'ev Mikhail M. , Vitt Sergei V. , Sizoy Vladimir F. , Sukhacheva Nina A. , Vasil'ev Gleb V. , Belikov Vasili M. 
Published: April 2003

AbstractCopolymerization of potassium Λ‐ and Δ‐bis[N‐(5‐methacryloylamino)salicylidene‐(S)‐norvalinato]‐cobaltate(III) (1 and 2) with acrylamide and N,N′‐methylenediacrylamide gives crosslinked gels. The behaviour of the amino acid moiety in the gel obtained from the isomer with the Δ(S,S) configuration does not differ from that of the monomeric model compound 4. The Λ(S,S) isomer gives gels, in which a part of the complex proves to be attached by both phenyl moieties to one polymeric chain forming a macrocycle. Deuterium exchange in such complexes proceeds with full retention of the configuration of the amino acid.
Study of photopolymers, 18. Synthesis and photochemical reaction of novel polymers with pendant photosensitive and photosensitizing groups
Authors: Lizawa Takashi , Nishikubo Tadatomi , Takahashi Eiji , Hasegawa Masaki 
Published: April 2003

AbstractSelf‐sensitized photosensitive polymers with pendant photosensitive and photosensitizing groups were prepared by reaction of polystyrene containing pendant chloromethyl and photosensitizing groups, with the potassium salts of photosensitive compounds such as cinnamic acid, crotonic acid, or 2‐cyano‐3‐(α‐styryl)acrylic acid in DMF using tetrabutylammonium bromide as phase transfer catalyst. The photochemical reactivity and the practical photosensitivity of the resulting polymers were measured by IR spectrometry and by the gray‐scale method, respectively. Pendant 4‐nitro‐1‐naphthyloxy and 4‐nitrophenoxy groups in the polymers show the highest photosensitizing activity for pendant cinnamoyl groups. The photochemical reactivity and the sensitivity of these polymers are affected by the content of photosensitizing units in the polymer skeleton, the glass transition temperature of the polymers, however, is not influenced. Pendant 2‐benzoylbenzoyl groups act as excellent photosensitizers for pendant crotonoyl groups, however, the photochemical reactivity of this polymer was found to be lower than that of the polymer with pendant cinnamoyl and suitable photosensitizing groups. Pendant 2‐cyano‐3‐(α‐styryl)acryloyl groups in the polymer, which exhibit high photochemical activity, are also sensitized by pendant methyleosin moieties.
Synthesis and characterization of some new polyamides containing azomethine groups in the polymer backbone, 2
Authors: Subramanian Pethannan , Venkatarao Krishnan 
Published: April 2003

AbstractNew aromatic polyamides containing azomethine groups in the backbone and also having different linking groups like CH2, CH2CH2, and O were synthesized by reacting 4,4′‐[1,4‐phenylenebis(methylidynenitrilo)]dibenzoyl dichloride (2) with some diamines 1a – d, 4, and 6 by the low temperature solution polycondensation method. The physical, spectral, and thermal properties of the synthesized polyamides were investigated. The effect of the nature of different linking groups on the properties of these aromatic polymides was explored by comparing their spectral and thermal data.
Synthese der cyclischen oligomere des butylenterephthalats
Authors: Müller Franz‐Josef , Kusch Peter , Windeln Johannes , Zahn Helmut 
Published: April 2003

AbstractCyclic oligomers of butylene terephthalate (16a – d) were synthesized by cyclocondensations of the corresponding dicarboxylic acid dichlorides (2 or 13) with diols (4, 10, or 15). The linear educts 2, 4, 10, 13, and 15 were obtained by stepwise synthesis. The resulting cyclic esters 16a – d were characterized by IR, NMR, and mass spectroscopy.
Polymer‐solvent interactions in mixed solvents, 5. Ionized ethyl, butyl, and hexyl vinyl ether‐maleic acid alternating copolymers in water/2‐chloroethanol mixtures
Authors: Apostolopoulos Michel , Morcellet Michel , Loucheux Claude 
Published: April 2003

AbstractViscosity and preferential solvation measurements were carried out on ionized maleic acidethyl, ‐butyl, and ‐hexyl vinyl ether alternating copolymers (i‐MA/EVE, i‐MA/BVE, and i‐MA/HVE, respectively) in water‐2‐chloroethanol mixtures. i‐MA/EVE and i‐MA/BVE are completely coiled and their preferential and absolute solvation by water and 2‐chloroethanol reflects their more or less hydrophilic or hydrophobic nature. For i‐MA/HVE, the viscosimetric and preferential solvation measurements suggest that, in 2‐chloroethanol rich mixtures, the polymer retains a hypercoiled conformation in which an important part of the hexyl side chains are screened form contact with both componenets of the solvent mixture.
Interaction between polynucleotides in aqueous NaCl solution, 5. Temperature dependence of the heat of formation of poly(I) · poly(C) duplex
Authors: Baba Yoshihiro , Kagemoto Akihiro , Beatty Charles L. 
Published: April 2003

AbstractThe heat of mixing of equimolar solutions of poly(I) and poly(C) containing various NaCl concentrations was measured at 288 and 308 K, and the heat of formation of Poly(I) · poly(C) duplex from the randomly coiled constituents, poly(I) and poly(C), was estimated from the heat of mixing with the aid of CD measurements. The temperature dependence of this heat of formation, ΔH, differs at lower and higher NaCl concentrations: In the region of NaCl concentration less than 0,5 mol · dm‐3, ΔH increases with temperature, while in the region of NaCl concentrations higher than 0,5 mol · dm‐3, ΔH decreases with temperature. The free energy change, ΔG, of the formation of poly(I) · poly(C) duplex decreases as the NaCl concentration increases, that is, the stability of poly(I) · poly(C) duplex increases with NaCl concentration. Moreover, the conformation of poly(I) · poly(C) duplex seems to differ at lower and higher NaCl concentration as derived from the CD spectra and the thermodynamic quantities.
Proton NMR studies on n‐paraffins in restricted molecular motion
Authors: Ando Isao , Hirai Toru , Fujii Yuji , Nishioka Atsuo , Shoji Akira 
Published: April 2003

AbstractThe 1H NMR spectra of guest molecules, n‐paraffins (n‐C5H12, n‐C6H14, n‐C7H16, n‐C9H20, nC10H22, nC11H24, n‐C12H26, n‐C15H32, n‐C16H34, n‐C21H44 and n‐C22H46), were measured in poly(γ‐benzyl‐L‐glutamate) liquid crystalline solution. The methylene signal of n‐paraffins is a doublet due to magnetic dipole‐dipole interaction. These results suggest that an n‐paraffin takes predominantly the extended form in the restricted molecular motion state and that its long axis orients in the same direction as the helical axis of poly(γy‐benzyl‐L‐glutamate) parallel to the magnetic field. The results are compared with the molecular motion and conformation of η n‐paraffins in α‐chloronaphthalene.
Controller order reduction with guaranteed performance via coprime factorization
Authors: Wang Jin‐Zhi , Huang Lin 
Published: April 2003

AbstractIn this paper the problems of the suboptimalH∞controller order reduction and strictly positive real (SPR) controller order reduction via coprime factorization are studied. The sufficient conditions to ensure the reduced order controllers also being suboptimalH∞controllers and SPR are given, respectively. The conditions presented may be considered as frequency weighted model reduction problems. We generalize the result ofCℱ(θ) approach in Goddard (Ph.D. Thesis, Trinity College, Cambridge, 1995) for controller order reduction with anH∞framework and the relationship between our results and some other existing results is established. Copyright © 2003 John Wiley & Sons, Ltd.
Turnaround in East Asian firms: evidence from ethnic Overseas Chinese communities
Authors: Bruton Garry D. , Ahlstrom David , Wan Johnny C. C. 
Published: April 2003

AbstractResearch done primarily in the United States has shown that firms in decline enjoy better odds of returning to health when strong measures are taken. The culture of the Overseas Chinese of East Asia has helped to shape the region's prior commercial success but it also impacts responses to firm decline and turnaround. This research provides the first empirical investigation of the turnaround strategies of Overseas Chinese firms in East Asia. The evidence gathered shows that the utility of the predominantly U.S. model of firm turnaround has limits in East Asia. In particular, the role of strong owner‐managers and the importance of relationships among business people constrain the applicability of prior U.S. research to East Asia. Copyright © 2003 John Wiley & Sons, Ltd.
Obstetric aspects of the Prader–Willi syndrome
Authors: Fong B. F. , de Vries J. I. P. 
Published: April 2003

AbstractThe Prader–Willi syndrome (PWS) is a complex, multisystem disorder. The syndrome affects the central nervous system, with a predilection for the hypothalamus. The clinical picture in PWS is very variable, and depends on the age of the affected child. Frequently, the most prominent features such as obesity, mental retardation and behavioral disorders do not become evident until the later childhood stage, which can lead to underdiagnosis or late diagnosis in early childhood. Because of the long‐term implications of this syndrome, it is important to recognize its features as soon as possible so that early counseling of parents and the affected child is possible. Because PWS can also lead to complications in both pregnancy and labor, proper diagnosis in the fetus can also help optimize perinatal care in affected children. In three cases we illustrate that certain combinations of obstetric symptoms such as polyhydramnios, diminished fetal movements, malpresentation and abnormal fetal heart rhythm can help alert clinicians to the possibility of this syndrome in fetuses. Copyright © 2003 ISUOG. Published by John Wiley & Sons, Ltd.
Holistic obstetrics: the origins of “natural childbirth” in Britain
Authors: Moscucci O 
Published: April 2003

Abstract
The term “natural childbirth” denotes an approach to childbirth characterised by a bias towards physical and mental hygiene in the management of pregnancy and labour. It emerged in Britain in the interwar period, partly as a response to the growing interventionism of mainstream obstetrics. Its appeal since then has rested on the belief that it could provide a holistic approach to maternity care, capable of addressing the needs of the “whole” patient. At the same time, “natural childbirth” has provided a means of expressing anxieties about the social, economic and political upheavals of the 20th century. This paper explores this complex set of beliefs and practices by examining the ideas of some British pioneers.
Raynaud’s phenomenon after radical radiotherapy for tumours of the head and neck
Authors: Westbury C B , Harrington K J , Rhys-Evans P , Archer D J , Searle A E , Henk J M , Black C M , Nutting C M 
Published: April 2003

Abstract
Endothelial cell injury is implicated in the development of radiation induced tissue damage and may also be involved in the pathophysiology of secondary Raynaud’s phenomenon. Two patients are presented in whom the typical symptoms and signs of Raynaud’s phenomenon developed as a late complication of radical radiotherapy. One had Raynaud’s of the tongue and one of the lip. Both patients had a prior history of primary Raynaud’s phenomenon and in each case the symptoms were repeatedly precipitated by sudden cold exposure. The possible pathogenesis of radiation induced Raynaud’s phenomenon in the head and neck region is discussed.
Evaluation of Different Antibiotics in Inhibiting Colonization of Vibrio cholerae O1 and O139 in the Rabbit Intestine
Authors: Chakrabarti M.K. , Bhattacharya M.K. , Bhattacharya J. , Bhattacharya S.K. , Mahalanabis D. 
Published: April 2003

The effects of furazolidone, erythromycin and azithromycin in inhibiting colonisation of <i>Vibrio cholerae</i> O1 and O139 in the rabbit intestine were tested. Both <i>V. cholerae</i> O1 and O139 highly colonised the gut in control rabbits. The colonisation of furazolidone-resistant strains in the rabbit intestine was prevented effectively by both erythromycin and azithromycin. In furazolidone-sensitive strains, the efficacies of erythromycin and azithromycin were very much comparable to furazolidone. These results suggested that azithromycin may be subjected to clinical trial in comparison to furazolidone and erythromycin for the treatment of cholera due to O1 and O139 infection in children.
The in vitro Effect of Macrolides on the Interaction of Human Polymorphonuclear Leukocytes with Pseudomonas aeruginosa in Biofilm
Authors: Takeoka Kaori , Ichimiya Tomoku , Yamasaki Tohru , Nasu Masaru 
Published: April 2003

The in vitro effect of macrolides at concentrations below the minimum inhibitory concentration (sub-MIC) on the interaction between <i>Pseudomonas aeruginosa</i> biofilm and human polymorphonuclear leukocytes (PMNs) was investigated by using a chemiluminescence assay. The PMN response to either mucoid or nonmucoid <i>P. aeruginosa</i> biofilm was strongly reduced compared with the response to planktonic bacteria (p < 0.01, p < 0.001, respectively). When biofilms were treated with erythromycin, clarithromycin, roxithromycin and azithromycin prior to incubation with PMNs, the chemiluminescence response was markedly enhanced as compared to untreated controls, and a dose-dependent effect was noted over the range of sub-MIC concentrations studied. In general, macrolides appeared to be slightly more active against mucoid biofilm. Azithromycin was shown to be the most active macrolide against <i>P. aeruginosa</i> biofilms. However, the treatment with sub-MICs of rokitamycin did not have any effect. On the other hand, treatment of planktonic bacteria with macrolides before being exposed to the PMNs did not affect the chemiluminescence response as compared to untreated controls. These findings suggest that macrolides inhibiting the biofilm formation of <i>P. aeruginosa</i> may facilitate the phagocytosis of bacteria by PMNs.
Pharmacodynamics of Intermittent- and Continuous-Infusion Cefepime Alone and in Combination with Once-Daily Tobramycin against <i>Pseudomonas aeruginosa</i> in an in vitro Infection Model
Authors: Tessier Pamela R. , Nicolau David P. , Onyeji Cyprian O. , Nightingale Charles H. 
Published: April 2003

Cefepime, a fourth-generation cephalosporin, is currently one of the primary agents used in combination with an aminoglycoside when treating <i>Pseudomonas aeruginosa</i> infections. The bactericidal activity of cefepime administered as intermittent doses (IT) or continuous infusion (CI) both alone and in combination with once-daily tobramycin (ODT) against two clinical strains of <i>P. aeruginosa</i> was compared using an in vitro infection model. Cefepime concentrations simulated human pharmacokinetics after a 1-gram Q12 regimen, or a 1-gram loading dose followed by a 2-gram Q24 CI regimen; the ODT regimen mimicked peak concentrations of ≥10 × MIC. All regimen simulations were run in duplicate over 48 h and a growth control (no antimicrobials added) was run concurrently. Strains tested, PSA5 and PSA10, had MICs of 2 and 8 μg/ml to cefepime, respectively; both MICs to tobramycin were 1.0 μg/ml. CI regimens resulted in concentrations approximately 6× and 2× the MIC for PSA5 and PSA10, respectively. The change in log<sub>10</sub> colony-forming units (CFU) per milliliter over time for both <i>P. aeruginosa</i> isolates was compared to initial inocula for all treatment regimens. Initial bolus doses of both IT and CI regimens resulted in a similar decrease in the log<sub>10</sub> CFU/ml of both organisms over the first 12 h of the study. After subsequent doses, however, both IT regimens showed greatly diminished bactericidal activity, while both CI regimens were persistently bactericidal without the observation of significant regrowth. As a result, a statistical difference in log<sub>10</sub> CFU/ml between both IT and CI regimens with and without ODT was realized at 24, 36 and 48 h for each isolate. Unlike IT dosing, CI cefepime alone or in combination with ODT optimizes bactericidal activity by maximizing the percent of the dosing interval that concentrations remained above the MIC resulting in undiminished bacterial inhibition when compared to IT regimens. These data further suggest that CI is the most efficient method of administration of β-lactam antibiotics.
[<sup>123</sup>I]β-CIT SPECT Visualizes Dopamine Transporter Loss in de novo Parkinsonian Patients
Authors: Müller T. , Farahati J. , Kuhn W. , Eising E.G. , Przuntek H. , Reiners C. , Coenen H.H. 
Published: April 2003

Parkinson’s disease (PD) is characterized by degeneration of dopaminergic neurons in the basal ganglia, which may be visualized by single photon emission computed tomography (SPECT) in combination with the cocaine analog methyl-3-β-(4-β[<sup>123</sup>I]iodophenyl)tropane-2β-carboxylate ([<sup>123</sup>I]β-CIT). The aim of our study was to correlate findings of SPECT with clinical data of 34 previously untreated, idiopathic parkinsonian patients [age: 59.58±10.03 (mean±SD) years; Hoehn and Yahr Scale (HYS) mean range: 1.97±0.83, ranges I–III; Unified PD Rating Scale 3.0 (UPDRS, 30.64±18.68) and 15 healthy controls (age 47.93±10.47 years). SPECT scans were performed with a single-head γ-camera 24 h after intravenous injection of [<sup>123</sup>I]β-CIT. Comparison of the striatum/cerebellum (S/C) ratio of [<sup>123</sup>I]β-CIT uptake of controls and parkinsonian subjects, subdivided according to their HYS range, was significant. No influence of age or sex was observed. Significant correlations were found between scores of the HYS, UPDRS parts I–III, part II, part III, and the S/C ratio of [<sup>123</sup>I]β-CIT uptake. Moreover, SPECT with the radiotracer [<sup>123</sup>I]β-CIT revealed side-to-side differences in parkinsonian patients and significant associations to contralateral clinical extrapyramidal symptomatology. Our data show that SPECT with [<sup>123</sup>I]β-CIT is a valuable tool for estimating disease severity in PD.