bluuebunny/crossref_metadata_2025 huggingface dataset:
ELECTRON-SPIN RESONANCE EVIDENCE OF THE QUANTUM SPIN GAP IN THE LiCu2O2
Authors: ZVYAGIN S. A. , CAO G. , BRUNEL L.-C. , CROW J.
Published: October 2002

Results of the high-frequency/field electron spin resonance investigation of the quantum S = 1/2 chain compound LiCu2O2 are presented. Spin-singlet ground state (which occurs in LiCu2O2 as a result of the spin-dimerization) is revealed at a temperature above T ~ 23 K. The size of the gap between the spin-singlet ground state and the excited triplet is found to be Δ = 72 K. Electron spin resonance study confirms a magnetic phase transition in LiCu2O2, which results in the collapse of the spin-singlet ground state at T < 23 K.
ELECTRON CORRELATION EFFECTS IN BIOLOGICAL MOLECULES
Authors: COX D. L. , ENDRES R. , KULKARNI R. V. , LABUTE M. , SINGH R. R. P.
Published: October 2002

Allosteric (conformation changing) proteins with transition metal atoms are at the heart of much important biological function (e.g., myoglobin hemoglobin used for storing and transporting oxygen in the bloodstream). In the case of myoglobin and hemoglobin, oxygen ligation to the iron center induces a spin crossover (high to low) coupled to a structural change; apart from the role of Hunds' exchange in the spin crossover, electron interaction effects have been ignored. We argue that the spin crossover/structure change observed in the similarly structured but far simpler cobalt valence tautomer molecules1 necessitates an inclusion of underscreened Kondo like correlations for a complete description of the energetics of the transition and dynamics, e.g., for x-ray absorption data. We carry this study out with Varma-Yafet-Gunnarsson-Schonhammer wave functions, which, in chemistry language, are basis set restricted configuration interaction in character. We briefly review the applicability of such wave functions to the description of the putative Kondo molecules cerocene (Ce[(CH)5]2) and ytterbocene bipyridine (Yb[(CH)5]2(bipy)) and to the problem of electron transfer in biological molecules and organic conductors, where anomalous long range tunneling may occur.

Research supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Division of Materials Research.
THE DRESDEN 100 T/10 ms PROJECT: A HIGH MAGNETIC FIELD FACILITY AT AN IR-FEL
Authors: DÖRR M. , ECKERT D. , ESCHRIG H. , FISCHER F. , FULDE P. , GROESSINGER R. , GRÜNBERGER W. , HANDSTEIN A. , HINZ D. , KRATZ R. , KRUG H. , LOEWENHAUPT M. , MÜLLER K.-H. , POBELI F. , SCHULTZ L. , SIEGEL H. , STEGLICH F. , VERGES P.
Published: October 2002

We have proposed to build a 100 T/10 ms, 70 T/100 ms, 60 T/1 s pulsed field user facility with a 50 MJ capacitor bank at the Forschungszentrum Rossendorf near Dresden. This would provide the appealing possibility to have access to Zeeman energies in the energy range of the infrared free-electron-lasers (5 μm to 150 μm; 2 ps; cw; > 10 W) now under construction at the radiation source ELBE (superconducting electron linear accelerator; 40 MeV; 1 mA; 2 ps; cw) in Rossendorf. The work is accompanied by computer simulations of the planned coil systems, of the power supply, and by the development of high-strength conductors aiming at a tensile strength of about 1.5 GPa at σ ≈ σ Cu/2 (microcomposite CuAg alloys and Cu-steel macro compounds).

With a view of gaining experience in the construction and operation of pulsed magnets, a pilot pulsed field laboratory was established at the Institute of Solid State and Materials Research Dresden (IFW Dresden). The laboratory includes short pulse magnets with peak field up to 60 T in a 24 mm bore and a rise time of about 10 ms (coil from NHMFL, Tallahassee), and a 40 T long pulse magnet with 24 mm bore and rise time of about 80 ms (coil from METIS, Leuven). The repetition rate of 20 min between pulses is limited by the cooling time of the coils. The coils are energized by a 1 MJ, 10 kV capacitor bank with some special features. With this set-up measurements of magnetization and magnetotransport on 4f-electron systems, for example RECu2, have been out in the temperature range of 1.5 to 300 K and at fields up to 52 T using high precision pick-up coils.
MEGAGAUSS CYCLOTRON RESONANCE IN SEMICONDUCTOR NANOSTRUCTURES AND DILUTED MAGNETIC SEMICONDUCTORS
Authors: MIURA N. , MATSUDA Y. H. , IKAIDA T.
Published: October 2002

We report the latest results of cyclotron resonance experiments on semiconductor nanostructures and diluted magnetic semiconductors (DMS) in very high magnetic fields up to 600 T produced by magnetic flux compression and the single turn coiled technique. Many new features were observed in the very high field range, such as characteristic behavior of low dimensional electrons, carrier dynamics or electron-electron interaction effects in quantum wells and quantum dot samples. In PbSe/PdEuTe quantum dots, which were regularly arranged to form an fcc superlattice, we observed an absorption peak with a splitting and a wavelength dependence of the absorption intensity. In DMS, such as CdMnTe and InMnAs, change of the carrier effective mass with Mn doping was studied in detail. We found anomalous mass increase with doping of magnetic ions. The amount of the observed mass increase cannot be explained by the k·p theory and suggests the importance of d-s or d-p hybridization.
WAVE FUNCTION OF THE TIME-DEPENDENT INVERTED HARMONIC OSCILLATOR
Authors: PEDROSA I. A. , GUEDES I.
Published: October 2002

Time-dependent mass and frequency inverted harmonic oscillator is discussed in light of the Lewis and Reisenfeld invariant method. The wave function is found in terms of the Weber function. As an example, we derive the wave function of the inverted Caldirola-Kanai oscillator.
CHARACTERIZATION OF CdZnTe CRYSTALS BY RESISTIVITY MEASUREMENTS AND CHEMICAL ETCHING
Authors: HOU Q. R. , CHEN Y. B. , CHEN H. , HE Y. J. , LIU K. Y.
Published: October 2002

CdZnTe crystals grown by the vertical Bridgman method were characterized by measuring their resistivity and chemical etching in the well-known Nakagawa etchant (3HF:2H2O2:2H2O, vol./vol.). It was found that the resistivity of the CdZnTe crystals was between 4.33 × 103 and 8.50 × 106 Ωcm. Defect densities were much higher around the periphery of some CdZnTe samples due to the influence of mechanical stress caused by contact with the crucible walls during the CdZnTe crystal growth. The sizes of the high defect density region ranged from 1.8 to 2.8 mm. Such high defect density region should be eliminated in order to make high-quality radiation detectors or prepare the substrates for the epitaxial growth of HgCdTe.
SOME RESULTS ON (PRE)KERNEL CATCHERS AND THE COINCIDENCE OF THE KERNEL WITH PREKERNEL
Authors: CHANG CHIH , LIAN CHRONG-HSIN
Published: October 2002

The paper is devoted on the one hand to (pre)kernel catchers and on the other hand to the coincidence of the kernel K with the prekernel Pr K. Sufficient conditions for the coincidence K = Pr K are given by the inclusions R* ⊆ X or L* ∩ R* ⊆ X. Here X denotes the imputation set. The two sets R* and L* consist of those preimputations of which the payoffs are bounded above by player's maximal marginal contribution or bounded below by player's minimal marginal contribution.
STRONG NASH EQUILIBRIUM IN MULTISTAGE GAMES
Authors: PETROSJAN L. A. , GRAUER L. V.
Published: October 2002

Infinite multistage games G with games Γ(·) played on each stage are considered. The definition of path and trajectory in graph tree are introduced. For infinite multistage games G a regularization procedure is introduced and in the regularizied game a strong Nash Equilibrium (coalition proof) is constructed. The approach considered in this paper is similar to one used in the proof of Folk theorems for infinitely repeated games. The repeated n-person "Prisoner's Dilemma" game is considered, as a special case. For this game a strong Nash Equilibrium is found.
DISCRETE TIME DYNAMIC GAMES WITH A CONTINUUM OF PLAYERS I: DECOMPOSABLE GAMES
Authors: WISZNIEWSKA-MATYSZKIEL AGNIESZKA
Published: October 2002

The purpose of this paper is to present some simple properties and applications of dynamic games with discrete time and a continuum of players. For such games relations between dynamic equilibria and families of static equilibria in the corresponding static games, as well as between dynamic and static best response sets are examined and an equivalence theorem is proven. The existence of a dynamic equilibrium is also proven. These results are counterintuitive since they differ from results that can be obtained in similar games with a finite number of players.

The theoretical results are illustrated with examples describing voting and exploitation of ecological systems.
CONSISTENCY FOR PROPORTIONAL SOLUTIONS
Authors: YANOVSKAYA ELENA
Published: October 2002

One of the properties characterizing cooperative game solutions is consistency connecting solution vectors of a cooperative game with finite set of players and its reduced game defined by removing one or more players and by assigning them the payoffs according to some specific principle (e.g., a proposed payoff vector). Consistency of a solution means that any part (defined by a coalition of the original game) of a solution payoff vector belongs to the solution set of the corresponding reduced game. In the paper the proportional solutions for TU-games are defined as those depending only on the proportional excess vectors in the same manner as translation covariant solutions depend on the usual Davis–Maschler excess vectors. The general form of the reduced games defining consistent proportional solutions is given. The efficient, anonymous, proportional TU cooperative game solutions meeting the consistency property with respect to any reduced game are described.
Packing of ruthenium sensitizer molecules on mostly exposed faces of nanocrystalline TiO2: crystal structure of (NBu4+)2[Ru(H2tctterpy)(NCS)3]2−·0.5 DMSO
Authors: Shklover V. , Nazeeruddin Md. K. , Grätzel M. , Ovchinnikov Yu. E.
Published: October 2002

An X‐ray crystal study of the new ‘black dye’ sensitizer tri(thiocyanato)(4,4′,4″‐tricarboxy‐2,2′:6′,2″‐terpyridine)ruthenium(II) is reported. In the crystal, strong hydrogen bonds form chains of ruthenium complex dianions with the O···O distances of 2.48–2.54 Å. From the molecular geometry of the dianions, structural models of their close packing on the (101) and (001) crystal surfaces of TiO2 (anatase) have been built. The maximum possible density of molecular packing noticeably exceeds the experimental value. The hydrogen bonding between the anions in monolayers, located on the TiO2 surface, is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Kinetics of esterification of cycloaliphatic epoxies with methacrylic acid
Authors: Srivastava Akanksha , Agrawal Sudha , Rai J. S. P.
Published: October 2002

The esterification of cycloaliphatic epoxy resins CER I and CER II containing glycidyl and cyclohexane epoxy groups, respectively, as their reactive units was carried out using a 1 : 0.9 stoichiometric ratio of resin and methacrylic acid in the presence of triphenylphosphine. The reaction was performed at 80, 85, 90, 95, and 100°C and it followed second‐order kinetics. The specific rate constants, calculated by regression analysis, were found to obey an Arrhenius expression. Kinetic and thermodynamic parameters, activation energy, frequency factor, entropy, enthalpy, and free energy of the reaction, revealed that the reaction was spontaneous and irreversible and produced a highly ordered activated complex. The reactivity of CER II was found to be higher than that of CER I. The difference in the reactivity of the cycloaliphatic epoxies was explained by proposing a reaction mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3197–3204, 2002
Synthesis and characterization of photosensitive copolymers of 4‐(4′‐nitrocinnamoyl)phenyl acrylate and glycidyl methacrylate
Authors: Subramanian K. , Reddy A. V. R.
Published: October 2002

Copolymers of 4‐(4′‐nitrocinnamoyl)phenyl acrylate (NCPA) and glycidyl methacrylate (GMA) were prepared in a methyl ethyl ketone solution with benzoyl peroxide as the initiator at 70°C. They were characterized with UV, IR, 1H‐NMR, 13C‐NMR, and gel permeation chromatography. Copolymer compositions were determined from 1H‐NMR spectra. The monomer reactivity ratios, determined by the method of Kelen and Túdös, were r1 (NCPA) = 1.22 and r2 (GMA) = 0.76. The initial decomposition temperatures of the copolymers were greater than 272°C, as observed by thermogravimetric analysis in air. The photocrosslinking properties of the polymer films were examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3264–3270, 2002
Thermal degradation and combustion of polymeric blends
Authors: Lomakin S. M. , Koverzanova E. V. , Usachev S. V. , Shilkina N. G. , Zaikov G. E.
Published: October 2002

The thermal stability of polymer blends was investigated by means of gas chromatography–mass spectroscopy (GC/MS) and thermal analysis. Evaluated changes in thermal stability can be attributed to blending. On the other hand, we were interested in whether blending may provide a method to control thermal stability and combustibility of polymeric materials. A new scheme of thermal degradation for polystyrene‐polydimethylsiloxane (PDMS) blend was suggested. In the case of polystyrene (PS) as a part of the blend, the products of degradation of PS diffuse through the phase boundary, which cause interaction with PDMS polymers. Apparently, PDMS acts as an inert component, slowing down the termination reaction by dilution of macroradicals formed in random scission degradation process of the PS component. On the other hand, it stabilizes the PS by means of interpolymer recombination, which leads to cross products of thermal degradation. Two of the degradation products: 2‐phenyl‐4(1′,3′,3′,5′,5′‐pentamethylcyclotrisiloxane)‐butane and 2‐phenyl‐4(1′,3′,3′,5′,5′,7′,7′‐heptamethylcyclotrisiloxane)‐butane were assigned to the products of cross‐interpolymer recombination which can accelerate the process of PDMS depolymerization by means of radical initiation of PS* fragments. The connection between a polymer thermal oxidative degradation and its combustion under diffusion flames condition was shown by using composition of polypropylene‐polypropylene‐co‐polyethylene (PP/PP‐co‐PE). In general, the solid‐phase polymer reaction can play a very important role in the reduction of polymer combustibility. It was shown that the composition of PP/PP‐co‐PE (62 : 38) has the highest induction period of autooxidation, which correlates with its combustibility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3300–3311, 2002
Development of low‐viscosity benzoxazine resins and their polymers
Authors: Wang Yong‐Xia , Ishida Hatsuo
Published: October 2002

With unsubstituted phenol, formaldehyde, and primary aromatic amines as the starting materials, a series of monofunctional benzoxazine resins with low viscosities at room temperature were developed. The polymerization behavior of these resins into thermosetting materials was monitored by differential scanning calorimetry. Stress relaxation of the obtained polybenzoxazines revealed these polymers to be chemically crosslinked networks. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2953–2966, 2002
Novel copolymers for electroluminescent devices
Authors: Wang Haiqiao , Li Xiaoyu
Published: October 2002

Two novel luminescent block copolymers (CE–PPV and CE–DMPPV), containing alternating distyrylbenzene [poly(phenylene vinylene) model oligomer] as light‐emitting units and crown‐ether segments as ionic conductive and spacer units were synthesized by use of a Wittig reaction between the dialdehyde monomer and 1,4‐xylylene‐bis(triphenylphosphonium bromide) or 1,4‐bis(triphenylphosphoniomethyl)‐2,5‐dimethoxybenzene dichloride. The synthesized polymers were characterized with FTIR, 1H‐NMR, UV–Vis, differential scanning calorimetry, and gel permeation chromatography. The number‐average molecular weights were 6896 with a polydispersity index of 1.75 for CE–PPV, and 9301 with a polydispersity index of 2.474 for CE–DMPPV, respectively. The decomposition temperatures and the glass‐transition temperatures were in the range of 395–411°C and 75–77°C, respectively. The electrochemical properties of the copolymers were evaluated and the highest occupied molecular orbital and the lowest unoccupied molecular orbit energy levels of the copolymers were estimated by cyclic voltammetry. Efficient light‐emitting diodes were successfully fabricated. The synthesis, characterization, and electroluminescent properties of the polymers are reported in this study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3316–3321, 2002
The ring‐opening polymerization of D,L‐lactide catalyzed by new complexes of Cu, Zn, Co, and Ni Schiff base derived from salicylidene and L‐aspartic acid
Authors: Sun Junquan , Shi Weiliang , Chen Deyu , Liang Chengfeng
Published: October 2002

D,L‐lactide (LA) was first successfully ring‐opening polymerized in melt by Schiff base complexes K[ML]nH2O [M = Cu(II), Zn(II), Co(II), Ni(II); n = 2, 2, 3, 3.5; H3L = L‐aspartic acid‐salicylidene Schiff base], which were prepared by Schiff base ligand derived from salicylidene and L‐aspartic acid and corresponding acetates. The effects of various complexes, the molar ratio of K[ML]nH2O/LA, the polymerization temperature, and time were studied in detail. The results show that all complexes studied have the ability to initiate the ring‐opening polymerization of D,L‐lactide in melt. More than 90% high polymerization conversion and narrow molecular weight distribution (MWD) can be obtained very easily. However, the Ni(II) complex shows better catalytic property than other complexes on the polymerization and the molecular weight (MW) of poly(D,L‐lactide) (PLA) produced. With a rise in temperature and a prolongation of time, the MW of PLA decreased remarkably. The MW of PLA prepared by all complexes is not very high, which might be related to the crystalline water of complexes. X‐ray study indicated that PLA produced by Ni(II) complex is an amorphous polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3312–3315, 2002
Surface grafting of polyester fiber with chitosan and the antibacterial activity of pathogenic bacteria
Authors: Hu S.‐G. , Jou C.‐H. , Yang M.‐C.
Published: October 2002

Three polyesters—poly(ethylene terephthalate), poly(2‐methyl‐1,3‐propylene terephthalate‐co‐ethylene terephthalate), and poly(1,4‐cyclohexylene terephthalate‐co‐ethylene terephthalate)—were preirradiated with 60Co‐γ‐rays. Then, acrylic acid and N‐vinylformamide were grafted to these irradiated fibers. Fibers grafted with N‐vinylformamide were further hydrolyzed with acid so that the amide groups would convert into amino groups, and they were treated with glutaraldehyde so that aldehyde groups would be introduced. Chitosan or chitooligosaccharide was then grafted to these fibers via either esterification or imine formation. Four pathogenic bacteria—methicillin‐resistant Staphylococcus aureus‐1 (MRSA), Staphylococcus aureus‐2, Escherichid coli, and Pseudomonas aeruginosa—were tested to determine the antibacterial activities of chitosan‐grafted and chitooligosaccharide‐grafted fibers. The results showed that grafting chitosan via imine formation could achieve a higher surface density for amino groups and give higher antibacterial activity to those four bacteria tested. The antibacterial activity for E. coli was the highest and that for MRSA was the lowest among the four bacteria tested. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2977–2983, 2002
Fluorescence method using labeled chromophores to study the curing kinetics of a polyurethane system
Authors: González‐Benito J. , Mikeš F. , Baselga J. , Lemetyinemm H.
Published: October 2002

A fluorescence method using labeled chromophores to study the curing kinetics of a polyurethane (PU) system was developed. A PU system based on fluorescent‐labeled hexamethylene diisocyanate and a polyol (polyether/polyester) was cured at different temperatures (25, 40, 50, and 65°C). The fluorescent response from the 5‐dimethylaminonaphtalene‐1‐(N‐2‐aminoethyl)sulfonamide and 4‐methacryloylamino‐4′‐nitrostilbene moieties chemically bonded to the PU system was monitored as a function of the curing time. With the fluorescence data, it was possible to model the kinetics of the curing process. Methods based on the fluorescence intensity ratio and the first moment of the fluorescent band emission were applied to determine the degree of curing of the PU system. In addition, it was possible to calculate an apparent activation energy for the curing process, and a value of 17 kJ/mol was obtained. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2992–3000, 2002
Thermally induced microstructural changes in cotton fibers: A free‐volume study
Authors: Ranganathaiah C.
Published: October 2002

I measured positron lifetime in natural polymer–cotton fibers as a function of isochronal annealing temperature in the range 27–290°C. The variations in the positron results indicated structural changes occurring in the cotton fibers and determined the glass‐transition temperature as 80°C. Activation energies were measured separately for the crystalline and amorphous regions, indicating the versatility of the technique. These values were close to the OH bond dissociation energy, suggesting OH bond dissociation, the most probable process occurring under thermal treatment. As an extension of the positron results, the molecular weight of the cotton fibers was determined to be 1,200,000 based on free volume, which was within the range suggested for cotton. There seemed to be an indication that crosslinking changed the spiral structure of cotton fibers to the network type. However, this needs to be validated by other measurements. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3336–3345, 2002
Melt versus solvent coating: Structure and properties of block–copolymer‐based pressure‐sensitive adhesives
Authors: O'Connor A. E. , Macosko C. W.
Published: October 2002

Pressure‐sensitive adhesives (PSAs) composed of a styrene–isoprene–styrene triblock copolymer and a midblock‐associating resin were prepared via solvent and hot‐melt coating. The formulations and thermal histories up to the point of coating were identical, yet significant differences in the properties were observed as a function of the coating method. The solvent‐coated PSA showed superior shear holding power, and the hot‐melt‐coated PSA performed better in tack and peel tests. Two factors resulting from the processing conditions were responsible for these property differences. The quick cooling process occurring after hot‐melt coating led to a poorly defined microstructure and, therefore, less physical crosslinking. Rheological data for melt‐pressed and solvent‐cast PSA films confirmed these microstructural differences. The increased solubility of the tackifier in the solvent additionally created a composition gradient in the solvent coating. Annealing improved the long‐range order of both hot‐melt and solvent coatings, producing a body‐centered cubic microstructure identified by small‐angle X‐ray scattering. This microstructure improved the shear strength of both types of adhesive coatings, whereas the peel and tack properties of the solvent coatings remained inferior to those of the hot‐melt coatings because of differences in the surface compositions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3355–3367, 2002
Simulations on structure performance of 3C thin‐wall injection‐molded parts
Authors: Chen Shia‐Chung , Wang Hsing‐Ling , Chen Juan‐Po , Peng Hsin‐Shu
Published: October 2002

Manufacturing of 3C (Computer, Communication, and Consumer Electronics) products toward weight reduction, thin‐wall, and minified‐size is an inescapable trend for the future 3C industries. However, the induced damage information from drop impact, including exterior housing fracture, liquid crystal display (LCD) cracking, solder‐joint breaking, or interior component failure, is still derived experimentally and involves very complicated parametric analyses, such as a dynamic impact process, drop orientation, contact behavior, and large deformation during the impact instance. In the present study, numerical simulations for the drop test and bending strength were applied to a thin‐wall computer dictionary (Model CD‐66) housing to understand the key factors that affect the part drop test performance. The appropriate modeling that would affect simulation accuracy as well as the associated nodal degree of freedom and computer time were also investigated. A housing of CD‐66 was redesigned to be 1 mm thick and structurally verified with two different plastics: polycarbonate (PC) and acrylonitrile butadiene styrene (ABS). The simplification of the PC board and LCD backlight circuit in finite element modeling (FEM) only causes about a 10% difference, while saving many modeling costs. The numerical simulations also indicate that both its bending strength and drop‐impact strength were decreased only about 5%, whereas the product quality still met its strength requirement if only the top housing plate thickness was reduced while the remaining sidewall thickness was kept unchanged. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3064–3071, 2002
Initiation and development of the heat‐affected zone in the vibration welding of polyvinylidene fluoride and its copolymers
Authors: Valladares D. , Cakmak M.
Published: October 2002

Using a servo hydraulically controlled vibration‐welding machine, the temporal and spatial development of hierarchical structure in the heat‐affected zone of Poly(vinylidene fluoride) homopolymer and a copolymer of vinylidene fluoride and hexafluorpropylene are investigated. The dynamical changes early in the welding process are rather complex, and start at highly localized regions that then develop rapid adhesive character. In subsequent stages, these regions coalesce and a wave pattern establishes with wave normals oriented in the vibration direction. The crests of the waves near the side surfaces then begin to extrude fibrillar structure. These fibers are also collected and extruded in the vibration direction with their long axes normal to the vibration direction. The production of such features is partly attributed to the high melt elasticity of these polymers that results in instability resulting in their production. X‐ray analysis indicates that the fibers are unoriented in their crystalline regions but electron microscopy studies show that a spiral orientation develops in the extruded fibers indicating that they underwent extension plus twisting deformation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3377–3388, 2002
Acidic and basic hydrolysis of poly(N‐vinylformamide)
Authors: Gu L. , Zhu S. , Hrymak A. N.
Published: October 2002

Poly(N‐vinylformamide) (PNVF) was synthesized and hydrolyzed to poly(vinylamine) (PVAm) in both HCl and NaOH solutions. The hydrolysis kinetics and the equilibrium hydrolysis were examined experimentally at different temperatures, polymer concentrations, and acid‐ or base‐to‐amide molar ratios. The hydrolysis kinetics strongly depended on temperature, polymer, and HCl or NaOH concentrations, but showed little dependence on PNVF molecular weight. The acid hydrolysis of PNVF exhibited limited conversions because of the electrostatic repulsion among the cationic amine groups generated during hydrolysis and proton hydrates. In the basic hydrolysis, complete amide conversions were observed when the NaOH/amide molar ratios were greater than unity. The effects of temperature and PNVF concentration on the equilibrium amide conversion appeared to be negligible in both acidic and basic hydrolysis. The equilibrium conversions of base hydrolysis were higher than those of acidic hydrolysis under the same reaction conditions. At NaOH/amide ratios of less than unity, the equilibrium hydrolysis experiments revealed that one base molecule could induce the hydrolysis of more than one amide group. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3412–3419, 2002
Retention of gallium ions from acidic solutions by pyridine strong‐base anion exchangers
Authors: Dulman Viorica , Buhaceanu Rodica , Luca Cornelia , Neagu Violeta
Published: October 2002

Using the batch method, the retention of Ga(III) from HCl solutions by two gel‐type pyridine strong‐base anion exchangers containing 1‐methyl‐ or 1‐butyl‐4‐vinylpyridinium chloride structural units, called S1 and S2 resins, respectively, was studied. The influence of the HCl and Ga(III) concentrations as well as of the contact time between the resin and the liquid phase was investigated. The parameters, which characterize the retention process, were estimated using Langmuir and Freundlich isotherms. Both resins exhibited a higher affinity for gallium ions from a 6M HCl solution. According to Langmuir isotherms, maximum retention capacities of 44.44 and 60 mg Ga(III)/g dry resin for the S1 and S2 resins, respectively, were obtained. Freundlich isotherms provide additional proof for a higher affinity of the S2 resin for Ga(III) from HCl solutions. It is clear that the substituent length increase on N+ atoms led to an increasing affinity of the pyridine strong base anion exchangers toward Ga(III). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3440–3444, 2002
Reactive melt blending of modified polyamide and polypropylene: Assessment of compatibilization by fractionated crystallization and blend morphology
Authors: Pompe Gisela , Pötschke Petra , Pionteck Jürgen
Published: October 2002

The melting and crystallization behavior of nonreactive and reactive melt‐mixed blends of polypropylene and carboxylic‐modified polyamide (mPA) as the dispersed phase was investigated. It was found that the size of the mPA particles decreases and the crystallization behavior of the mPA particles changes in dependence on the mixing time of the blends with oxazoline‐modified PP (mPP). This indicates that an in situ reaction occurs between the oxazoline groups of mPP and the carboxylic acid groups of mPA, resulting in a compatibilizing effect. In blends with mPP, the crystallization of the dispersed mPA phase splits into two steps. Below a critical particle size, the mPA does not crystallize at temperatures typical for bulk crystallization. These finely dispersed mPA particles crystallize coincidently with the PP phase, and this part increases with increasing mixing time. Analysis of the crystallization heat of both steps in connection with the particle volume distribution permits the estimation of the critical particle size to be ≤4 μm. These investigations showed that the effect of fractionated crystallization can be used to follow the morphology development and to evaluate the efficiency of compatibilizing interfacial reactions during processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3445–3453, 2002
High serum YKL‐40 level after surgery for colorectal carcinoma is related to short survival
Authors: Cintin Christina , Johansen Julia S. , Christensen Ib Jarle , Price Paul A. , Sørensen Steen , Nielsen Hans Jørgen
Published: October 2002

BACKGROUND

YKL‐40 is a member of family 18 glycosyl hydrolases. YKL‐40 is a growth factor and may stimulate migration of endothelial cells. YKL‐40 may also play a role in inflammation and degradation of connective tissue. Elevated preoperative serum YKL‐40 levels in patients with colorectal carcinoma are associated with a significantly poorer prognosis compared to patients with normal serum YKL‐40. In the current study the authors evaluated the value of serum YKL‐40 in monitoring patients with colorectal carcinoma.

METHODS

YKL‐40 was determined by an in‐house radioimmunoassay method in serum obtained pre‐ and postoperatively from 324 patients who underwent curative resection (Dukes Stage A: 47; B: 148; C: 119; and D: 10). The patients were followed with serum YKL‐40 levels every 6 months postoperatively, and the median followup time was 82 months (range, 68–95). In that period 146 patients died.

RESULTS

Serum YKL‐40 was significantly decreased in the first postoperative blood sample in 62% of patients with high preoperative levels. In addition, patients with high serum YKL‐40 (adjusted for age) six months after curative operation had significantly shorter survival times (P = 0.0002) and shorter relapse free intervals (P = 0.004) than patients with normal postoperative serum YKL‐40. This result was independent of simultaneous serum carcinoembryonic antigen levels at six months. Analysis of survival by scoring serum YKL‐40 as a time‐dependent covariate in a Cox regression analysis showed that patients exhibiting elevated serum YKL‐40 had an increased hazard for death within the following six months compared to those patients with normal serum YKL‐40 level (hazard ratio [HR] = 9.6, 95% confidence interval [CI]: 6.0–15.5, P < 0.0001). Multivariate analysis including Dukes stage, age, gender, and tumor location as well as the time‐dependent serum YKL‐40 showed that high serum YKL‐40 was an independent prognostic variable of survival (HR = 8.5, 95% CI: 5.3–13.7, P < 0.0001).

CONCLUSIONS

These results suggest that determination of serum YKL‐40 during followup of patients operated on for colorectal carcinoma might be useful for monitoring curatively resected patients. Cancer 2002;95:267–74 © 2002 American Cancer Society.

DOI 10.1002/cncr.10644
The impact of androgen deprivation on quality of life after radical prostatectomy for prostate carcinoma
Authors: Fowler Floyd J. , McNaughton Collins Mary , Walker Corkery Elizabeth , Elliott Diana B. , Barry Michael J.
Published: October 2002

BACKGROUND

Androgen deprivation is commonly prescribed for men with a rising prostate specific antigen level after radical prostatectomy, despite scant evidence regarding its efficacy and side effects. In the current study, the authors compared measures of health‐related quality of life (HRQOL) in men who were treated with androgen deprivation after radical prostatectomy with those for men who underwent surgery but were not treated with androgen deprivation.

METHODS

Medicare Provider and Analysis and Review (MedPAR) files were used to identify men who had undergone radical prostatectomies between 1991–1992. Medicare Part B data then were used to select two samples: men who subsequently were androgen deprived and those who were not. In 1999, a mail survey was administered that addressed a range of disease‐related and treatment‐related issues, including HRQOL. Age‐adjusted comparisons of responses to seven multiitem measures of HRQOL were performed.

RESULTS

The overall response rate was 82%. On all seven HRQOL measures (impact of cancer and treatment, concern regarding body image, mental health, general health, activity, worries about cancer and dying, and energy), there were statistically significant decrements associated with androgen deprivation.

CONCLUSIONS

Patients and physicians must weigh the price patients pay with regard to HRQOL against the uncertain benefits of early androgen deprivation. Cancer 2002;95:287–95. © 2002 American Cancer Society.

DOI 10.1002/cncr.10656
The significance of the amount of myometrial invasion in patients with Stage IB endometrial carcinoma
Authors: Alektiar Kaled M. , Mckee Andrea , Lin Oscar , Venkatraman Ennapadam , Zelefsky Michael J. , Mychalczak Boris R. , Mckee Brady , Hoskins William J. , Barakat Richard R.
Published: October 2002

BACKGROUND

The 1988 International Federation of Gynecology and Obstetrics (FIGO) staging system for endometrial carcinoma defined Stage IB as disease with invasion of less than one‐half of the myometrium, although most of the data on prognostic factors are based on invasion of the inner one‐third, middle one‐third, or outer one‐third of the myometrium. The objective of this study was to determine whether the depth of myometrial invasion is correlated with outcome in patients with Stage IB endometrial carcinoma.

METHODS

Between November, 1987 and June, 1998, 251 patients with Stage IB endometrioid adenocarcinoma of the uterus underwent simple hysterectomy followed by intravaginal brachytherapy. The depth of myometrial invasion was less than or equal to one‐third (Group I) in 191 of 251 patients (79%) and greater than one‐third to less than one‐half (Group II) in 52 of 251 patients (21%). Comprehensive surgical staging (CSS) was done in 12% of patients. The two groups were balanced with regard to age (< 60 years vs. ≥ 60 years), FIGO grade, lower uterine segment involvement (LUSI), CSS, and the use of postoperative external‐beam radiation. The rate of capillary‐like space invasion (CLSI), however, was 9% in Group I compared with 25% in Group II (P= 0.002). The median follow‐up was 58 months.

RESULTS

The overall 5‐year actuarial local‐regional control (LRC), disease free (DFS) survival, and overall survival (OS) rates were 95%, 92%, and 92%, respectively. These end points, however, did not vary significantly between the two groups. The 5‐year LRC, DFS, and OS rates in Groups I and II were 96% versus 95%, respectively (P= 0.9); 92% versus 94%, respectively (P= 0.7); and 92% versus 90%, respectively (P= 0.5). On multivariate analysis, the influence on outcome of age, grade, amount of myometrial invasion, LUSI, and CLSI was evaluated. Only age ≥ 60 years and FIGO Grade 3 were correlated with poor DFS (P= 0.02 andP= 0.03, respectively) and OS (P= 0.001 andP= 0.01, respectively).

CONCLUSIONS

Based on this study, in patients with Stage IB endometrial carcinoma, the amount of myometrial invasion, defined as invasion less than or equal to one‐third of the myometrium versus invasion greater than one‐third and less than one‐half of the myometrium, did not appear to influence outcome. Age ≥ 60 years and FIGO Grade 3, however, emerged as independent prognostic factors for poor DFS and OS. Cancer 2002;95:316–21. © 2002 American Cancer Society.

DOI 10.1002/cncr.10660
New WHO histologic classification predicts prognosis of thymic epithelial tumors
Authors: Chen Gang , Marx Alexander , Wen‐Hu Chen , Yong Jiang , Puppe Bernhard , Stroebel Philipp , Mueller‐Hermelink Hans Konrad
Published: October 2002

BACKGROUND

In 1999, a World Health Organization (WHO) committee published histologic criteria for distinct thymoma entities (labeled as Type A, AB, B1, B2, B3 thymomas) and for the heterogeneous group of thymic carcinomas, collectively called Type C thymomas. Whether WHO‐defined histologic thymoma subtypes are of independent prognostic relevance has yet to be proved.

METHODS

Two hundred thymomas from the Shanghai Chest Hospital with a mean follow‐up time of 15 years (range, 1–246 months) were studied for the relevance of WHO histologic subtype and other factors (stage, therapy, and myasthenia gravis [MG]) for survival.

RESULTS

In order of frequency, 68 patients (34.0%) had Type AB, 39 (19.5%) had Type B2, 36 (18.0%) had Type C, 27 (13.5%) had Type B3, 17 (8.5%) had Type B1, and 8 (4.0%) had Type A thymoma. Five cases (2.5%) were rare thymomas not mentioned in the WHO classification. Survival data showed significant differences among the histologic subtypes (log rank test: P < 0.001). Among patients with Type A and AB thymomas, none died of tumor; of the Type B1 thymoma patients, only one (5.9%) died at 22 months. Type B2, B3, and C thymomas had a significantly worse prognosis with 5‐year survival rates of 75.0%, 70.0%, and 48.0%, respectively. Ninety‐six patients (48.0%) were in Masaoka Stage I, 26 (13.0%) were in Stage II, 65 (32.5%) were in Stage III, and 13 (6.5%) were in Stage IV. Stage was highly significant in predicting survival (log rank, test P < 0.001). The association between histologic subtype and invasive behavior (stage) was statistically significant (P < 0.001). However, histology was an independent predictive factor of survival in Stage I and II thymomas: Type B2, B3, and C thymomas had a worse prognosis than Type A, AB, and B1 thymomas (log rank test: P < 0.003). Thirty patients (15.0%) presented with MG. MG was significantly more frequent in Type B2 and B3 than in Type A, AB, and B1 thymomas (P < 0.01). On multivariate analysis, MG had no adverse effect on survival (P = 0.17). Radiation or chemotherapy improved patients' survival at 5 and 10 years in Type B2, B3, and C thymomas (log rank test: P < 0.003).

CONCLUSIONS

Tumor stage is the most important determinant of survival in thymoma patients, but the WHO histologic subtype is an independent prognostic factor in Stage I and II thymomas, among which WHO Type A, AB, and B1 thymomas form a low‐risk group. Patients with high‐risk thymomas might profit from novel adjuvant radiochemotherapy regimens. Cancer 2002;95:420–9. © 2002 American Cancer Society.

DOI 10.1002/cncr.10665
Salvage high‐dose chemotherapy in patients with germ cell tumors
Authors: Rosti Giovanni , De Giorgi Ugo , Salvioni Roberto , Papiani Giorgio , Sebastiani Loretta , Argnani Marzia , Monti Giuseppe , Ferrante Patrizia , Pizzocaro Giorgio , Marangolo Maurizio
Published: October 2002

BACKGROUND

High‐dose chemotherapy (HDCT) followed by hematopoietic stem cell support (HSCS) potentially may be curative in patients with germ cell tumor (GCT) who develop recurrent tumors or who have an inadequate response after receiving standard‐dose chemotherapy. The authors report their experience with HDCT as salvage therapy for patients with GCT.

METHODS

Between 1986 and 2000, 84 patients with GCT, with a median age 29 years (range, 15–50 years), were treated with 105 courses of HDCT with HSCS. Patients were stratified into good, intermediate, and poor risk categories according to a validated prognostic index.

RESULTS

Overall, 28 patients (33%) have been continuously disease free. In the good risk group, 24 patients (69%) have been continuously disease free compared with 4 patients (13%) in the intermediate risk group (P < 0.001) and 0 patients in the poor risk group (P < 0.001). Treatment‐related mortality occurred only among patients in the poor risk (n = 6 patients) and the intermediate risk groups (n = 4 patients).

CONCLUSIONS

In the authors' experience, HDCT induced impressive long‐term remissions as salvage treatment among patients in the good risk group. Moreover, the use of validated prognostic classifications may contribute to a better definition of the role of HDCT other than improving the outcome of patients with GCT. The definitive statement on the possible role of HDCT in patients with GCT will derive from the ongoing Phase III randomized studies. Cancer 2002;95:309–15. © 2002 American Cancer Society.

DOI 10.1002/cncr.10672
Treatment of intracranial metastatic esthesioneuroblastoma
Authors: Chamberlain Marc C.
Published: October 2002

BACKGROUND

Esthesioneuroblastoma (ENB) is an uncommon tumor that may metastasize to the central nervous system (CNS). To the authors' knowledge there is no current consensus regarding treatment. The current study was conducted to determine the toxicity and response rate of combined modality therapy in the treatment of patients with ENB metastatic to the brain.

METHODS

Six patients (2 men and 4 women) ranging in age from 47–61 years (median age, 53.5 years) with ENB had clinical and neuroradiographic evidence of CNS metastases (brain parenchyma in 6 patients and leptomeningeal metastases in 3 patients). CNS‐directed therapy included radiotherapy (to the brain in three patients and to the spine in two patients) and chemotherapy (systemic in six patients and regional in three patients). Systemic chemotherapy was comprised of carboplatin, lomustine, and vincristine administered every 2 months. Patients were evaluated by neuroradiographic and neurologic examination every other month.

RESULTS

Between 1–6 cycles of systemic chemotherapy were administered (median, 4.5 cycles). and 6–19 cycles of regional chemotherapy were administered (median, 17 cycles). Toxicity included aseptic meningitis (three patients), radiation enteritis (one patient), and ≥ Grade 3 (according to the National Cancer Institute Common toxicity Criteria) myelosuppression (four patients). Two patients required hospitalization for neutropenic fever and two patients required a transfusion (platelets in two patients and red blood cells in one patient). No treatment‐related deaths were reported. A partial response was achieved in four patients, and two patients demonstrated progressive disease. The median duration of response was 9 months (range, 2–12 months). Overall survival ranged from 3–13 months (median, 10.5 months). The cause of death was progressive parenchymal brain disease in three patients, systemic disease in two patients, and leptomeningeal disease in one patient.

CONCLUSIONS

In the small cohort of patients in the current study, combined modality therapy was found to have modest toxicity and palliative efficacy. Cancer 2002;95:243–48. © 2002 American Cancer Society.

DOI 10.1002/cncr.10679
Patients' experiences of homework tasks in cognitive behavioural therapy for psychosis: a qualitative analysis
Authors: Dunn Hazel , Morrison Anthony P. , Bentall Richard P.
Published: October 2002

This paper examines the experiences of individuals who agreed to undertake homework as part of cognitive behavioural therapy for psychosis. It attempts to identify factors that individuals believe influence homework compliance and thereby alert therapists to their possible impact, and, using grounded theory, dispel the myth that individuals with psychosis cannot meaningfully express their experiences and views. Ten participants, who either did (six) or did not (four) comply with homework were interviewed and a grounded theory approach was used to understand and generate theories relating to their completion of homework assignments. The factors cited as affecting homework compliance were motivation, recall of the assignment, difficulty, putting off, understanding of the rationale, perceived benefits, insight, effort and relevance. The most cited theme was insight, with four of the high compliance group accounting for 21 references and three of the low compliance group accounting for nine references. However, the high compliance group gained insight into problem development, maintenance and the use of effective strategies to realize goals whereas the low compliance group gained only an identification of their problems and an understanding of their development. Three participants in the low compliance group believed that their assignments were sometimes irrelevant to their needs but this was true of only one out of the six in the high compliance group. Further research into assessing and addressing non‐acceptance of treatment rationale may be indicated. Copyright © 2002 John Wiley & Sons, Ltd.
Differential expression of Musashi1 and nestin in the adult rat hippocampus after ischemia
Authors: Yagita Yoshiki , Kitagawa Kazuo , Sasaki Tsutomu , Miyata Takaki , Okano Hideyuki , Hori Masatsugu , Matsumoto Masayasu
Published: October 2002

Both nestin and the neural RNA‐binding protein Musashi1 (Msi1) are expressed in neural stem cells in the subventricular zone. Neurogenesis in the hippocampus has received much attention, so we evaluated the expression of Msi1 and nestin in the adult rat hippocampus after transient forebrain ischemia. Both Msi1 and nestin were induced in the reactive astrocytes after ischemia, especially in the CA1 region, until 35 days after ischemia. Induction of both molecules suggested that reactive astrocytes might have immature characteristics. In the subgranular zone (SGZ) of the hippocampal dentate gyrus, Msi1‐positive cells formed clusters after ischemia. These cells were labeled by bromodeoxyuridine (BrdU) but did not express glial fibrillary acidic protein. In contrast, very few nestin‐positive cells were labeled by BrdU. Our results suggest that neuronal progenitor cells in the SGZ expressed Msi1 but not nestin. © 2002 Wiley‐Liss, Inc.