bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and crystallization of melt‐mixed poly(ethylene terephthalate)/poly(ethylene isophthalate) blends
Authors: Kint Darwin P. R. , Martínez de Ilarduya Antxon , Sansalvadó A. , Ferrer Josep , Muñoz‐Guerra Sebastián
Published: October 2003

Physical blends of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI), abbreviated PET/PEI (80/20) blends, and of PET and a random poly(ethylene terephthalate‐co‐isophthalate) copolymer containing 40% ethylene isophthalate (PET60I40), abbreviated PET/PET60I40 (50/50) blends, were melt‐mixed at 270°C for different reactive blending times to give a series of copolymers containing 20 mol % of ethylene isophthalic units with different degrees of randomness. 13C‐NMR spectroscopy precisely determined the microstructure of the blends. The thermal and mechanical properties of the blends were evaluated by DSC and tensile assays, and the obtained results were compared with those obtained for PET and a statistically random PETI copolymer with the same composition. The microstructure of the blends gradually changed from a physical blend into a block copolymer, and finally into a random copolymer with the advance of transreaction time. The melting temperature and enthalpy of the blends decreased with the progress of melt‐mixing. Isothermal crystallization studies carried out on molten samples revealed the same trend for the crystallization rate. The effect of reaction time on crystallizability was more pronounced in the case of the PET/PET60I40 (50/50) blends. The Young's modulus of the melt‐mixed blends was comparable to that of PET, whereas the maximum tensile stress decreased with respect to that of PET. All blend samples showed a noticeable brittleness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3076–3086, 2003
Morphologies of polyethylene–ethylene/propylene/diene monomer particles in polypropylene‐rich polyolefin blends: Flake structure
Authors: Nedkov Todor , Lednický František
Published: October 2003

Morphologies of polyethylene–ethylene/propylene/diene monomer (PE/EPDM) particles in 93/7 polypropylene (PP)/PE blends were investigated. SEM micrographs of KMnO4‐etched cut surfaces and fracture surfaces of the blends revealed the existence of the “flake” structure. In the particles, crystalline PE formations with flake shape, which remain after etching, are called flakes. In addition to the PE‐crystalline flakes, amorphous PE, located between PE crystalline lamellae and EPDM rubber, complement the flake structure. The flakes are usually linked with the PP matrix, as seen in the heptane‐treated cut surfaces. These links, although observed with compatibilized samples, originate from the crystalline nature of PE particles, if no compatibilizer is added. Separately, the morphology of Royalene (consisting of high‐density PE and EPDM rubber, used as a PP/PE compatibilizer) was investigated by low‐voltage scanning TEM. The interaction of the components in the PE/EPDM blends can explain the formation of the flakes and toughening of the PP/PE blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3087–3092, 2003
Study on the synthesis of brominated epoxy resins
Authors: Król Piotr , Król Bożena , Dziwiński Euzebiusz
Published: October 2003

The GC/MS/Py method, thermogravimetric analysis (TG), MALDI‐TOF spectrometry, and IR spectra were utilized to investigate structures and thermal stability of brominated epoxy resins synthesized in the reaction of epichlorohydrin (ECH) and tetrabromobisphenol A (TBBA), with varied molar rates of monomers and varied condensation temperatures. A Rheotest viscometer was employed to test rheological properties of the resins, while their mechanical properties were determined after hardening with phthalic anhydride. The research work revealed that the optimum synthesis conditions were ECH : TBBA = 5 : 1, and the condensation temperature reasonably low (e.g., 40°C). The basic properties of the synthesized resins were found to be comparable to those of the commercial product D.E.R. 542 offered by Dow Plastics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3122–3134, 2003
New arylidene–siloxane polyethers: Liquid‐crystalline and photosensitive properties
Authors: Racleş Carmen , Airinei Anton , Cozan Vasile , Cazacu Maria , Sajo Istvan E.
Published: October 2003

By polycondensation reactions, starting from α, ω‐bis(chloromethyl)polydimethylsiloxanes with different molecular weights and 2,6‐bis(4‐hydroxybenzylidene)cyclohexanone, new polyethers were obtained. The structure of resulting polymers was confirmed by IR and 1H‐NMR spectroscopy and their thermal properties and mesophase behavior were studied by TGA, DSC, and polarizing light microscopy. Depending on the length of the siloxane spacer, some of the obtained compounds exhibited thermotropic liquid‐crystalline properties. A possible smectic texture was investigated by X‐ray diffraction measurements at room temperature. A decrease of the transition temperatures values was observed as the spacer length increased. The photochemical behavior of the siloxane polyethers was studied by ultraviolet absorption spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3093–3099, 2003
Modified chitosan. II. H‐chitoPAN, a novel pH‐responsive superabsorbent hydrogel
Authors: Pourjavadi A. , Mahdavinia G. R. , Zohuriaan‐Mehr M. J.
Published: October 2003

Chitosan was modified with polyacrylonitrile (PAN) through ceric‐initiated graft copolymerization. The chitosan‐g‐PAN product was saponified using sodium hydroxide aqueous solution to prepare a novel superabsorbent hydrogel, H‐chitoPAN. Duration of completing the saponification reaction as well as the water absorbency capacity of the hydrogel was decreased with increasing the alkaline concentration. Either chitosan‐g‐PAN or H‐chitoPAN was characterized by FTIR spectroscopy and DSC, TGA, and DTG thermal methods. According to FTIR, all the nitrile groups were converted to carboxylate and carboxamide groups. Both modified chitosans exhibited enhanced thermal stability over chitosan. The H‐chitoPAN superabsorbent hydrogel was recognized to be highly responsive to pH. Study of net effect of H+/OH− concentration (in absent of buffer solution) showed several sharp and large volume changes vs small pH variation in the range of 2–13. This abrupt swelling behavior was explained based on variety of pH‐dependent interactions of functional groups incorporated in the gel network by an external pH modulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3115–3121, 2003
Effect of low molecular weight polybutadiene as processing aid on properties of silica‐filled styrene–butadiene rubber compounds
Authors: Choi Sung‐Seen , Park Byung‐Ho , Nah Changwoon
Published: October 2003

Because silica has strong filler–filler interactions, a silica‐filled rubber compound shows a poor filler dispersion compared to a carbon black‐filled one. Improvement of the filler dispersion in silica‐filled styrene–butadiene rubber (SBR) compounds was studied using low molecular weight polybutadiene (liquid PBD) with the high content of 1,2‐unit. By adding the liquid PBD to the silica‐filled SBR compound, the filler dispersion and flow property are improved. The cure time and cure rate become faster as the 1,2‐unit content of the liquid PBD increases for the compounds containing the liquid PBD. The crosslink density increases linearly with increase in the 1,2‐unit content of the liquid PBD. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3135–3140, 2003
Dynamic mechanical properties of sandwich‐structured epoxy beam composites containing poly(ethyleneterephthalate)/poly(ethyleneglycol) copolymer with shape memory effect
Authors: Chun Byoung Chul , Cha Sang Hyuk , Park Chul , Chung Yong‐Chan , Park Myung Ju , Cho Jae Whan
Published: October 2003

To make smart vibration‐controlling composite laminate, a few poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers with shape memory ability were prepared. After selecting the best composition of PET–PEG copolymer in mechanical properties, a crosslinking agent such as glycerine, sorbitol, or maleic anhydride (MA) was included for crosslinked copolymer, followed by analysis of its effect on mechanical, shape memory, and damping properties. The highest shape recovery was observed for copolymer with 2.5 mol % of glycerine, and the best damping effect indicating vibration control ability was from copolymer with 2.5 mol % of sorbitol. With the optimum copolymers in hand, sandwich‐structured epoxy beam composites fabricated from an epoxy beam laminate and crosslinked PET–PEG copolymer showed that impact strength increased from 1.9 to 3.7 times depending on the type of copolymer, and damping effect also increased as much as 23 times for the best case compared to epoxy laminate beam alone. The resultant sandwich‐structured epoxy beam composite can be utilized as structural composite material with vibration control ability, and its glass transition temperature can be controlled by adjustment of PET, PEG, or crosslinking agent composition. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3141–3149, 2003
Preparation and properties of a biodegradable polymer as a novel drug delivery system
Authors: Liu Yu , Guo Li Kun , Huang Long , Deng Xian Mo
Published: October 2003

Poly (DL‐lactic acid‐co‐glycolic acid)‐co‐poly(ethylene glycol) was synthesized by bulk ring‐opening polymerization of DL‐lactide/glycolide/poly(ethylene glycol) using stannous chloride as an initiator. The molecular structure of the copolymer was analyzed by IR, 1H NMR, and DSC. The degradation behavior of copolymer was assayed by the reduction of molecular weight, the loss‐in‐mass, and the changes of pH value for degradation medium. The different contents of PGA and PEG in the molecules of the copolymer could control the degradation rate of polymer. Human Serum Albumin (HSA) was chosen as the model hydrophilic drug and encapsulated in the copolymer. The HA‐loaded copolymer microspheres were characterized by the diameter, diameter distribution of the microspheres, and the loading efficiency. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3150–3156, 2003
Molecular migration of aromatic liquids into a commercial fluoroelastomeric membrane at 30, 40, and 50°C
Authors: Kulkarni Sangeeta B. , Kariduraganavar Mahadevappa Y. , Aminabhavi Tejraj M.
Published: October 2003

A study of sorption profiles and diffusion anomalies of benzene, methyl‐substituted benzenes, and other substituted benzenes (viz., chlorobenzene, nitrobenzene, bromobenzene, and anisole) into commercial fluoroelastomer (FC‐2450) was carried out by gravimetric method. The liquid sorption was studied at 30, 40, and 50°C and the results were analyzed in terms of Fick's diffusion equation. Liquid concentration profiles were also computed by using Fick's equation with the appropriate initial and boundary conditions and these are presented as a function of penetration depth of molecular migration and time of immersion. The temperature dependencies of sorption, diffusion, and permeation were used to compute the Arrhenius activation parameters and the results were discussed in terms of molecular size of liquids and interactions. Similarly, the diffusion coefficients and activation energies for diffusion exhibit systematic dependence on the size of the penetrant molecules and in some cases these are influenced by the interactions between the membrane and liquid molecules. The results reported here are useful in the applications of fluoroelastomer in hazardous waste chemical ponds and other similar situations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3100–3106, 2003
Kinetic analysis of thermal degradation in poly(ethylene–vinyl alcohol) copolymers
Authors: Alvarez V. A. , Ruseckaite R. A. , Vázquez A.
Published: October 2003

Thermal analysis of EVOH copolymers with different ethylene content, were performed by TGA/DTGA under dynamic conditions. Apparent kinetic parameters were determined using different classical kinetic approaches. The apparent activation energy values obtained confirm that thermal stability of EVOH increases with ethylene content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3157–3163, 2003
Electrical polarization effects on LDPE morphology
Authors: Robert R. , de Souza G. P. , Juraitis K. R. , Akcelrud L.
Published: October 2003

The thermal and dynamic mechanical behavior of polarized low‐density polyethylene (LDPE) was investigated, by applying electric fields in the range of 5.37 to 31.7 MV/m, for 2.75 to 43.5 h. The polarization strongly affected DSC and DMA spectra, indicating that a new and more ordered phase is formed, which disappears gradually after the removal of the electrical field. A shift of −21.3°C was found in the DMTA spectra for the Tg of the polarized material, and no changes could be found in comparing the results of WAXS analyses of the original and treated materials. Very similar effects were observed with mechanical loading of the materials, leading to the conclusion that the amorphous phase of LDPE might be orienting under high electric fields in a similar manner. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3107–3114, 2003
A scheduling scheme for variable‐length packets in an input‐buffered ATM switch with priority of active buffer
Authors: Nakaki Yousuke , Okazaki Kohei , Sakamoto Kenji , Nishino Yoshiyuki , Sasase Iwao
Published: October 2003

In ATM (asynchronous transfer mode) we propose a VOQ (virtual output queuing) switch in which the same number of buffers as the number of output ports are provided in each input port, serving as an input‐buffered switch to avoid HoL (head of line) blocking. In addition, in order to handle the recent increase of IP traffic, the IP‐PIM (IP‐parallel iterative matching) scheme is proposed as the scheduling scheme for the VOQ switch using variable‐length packets. However, the IP‐PIM scheme has the problem that the queue lengths in other buffers are increased, since cells belonging to the same packet are always handled continuously, which degrades the packet loss probability. Consequently, this paper proposes a scheduling scheme with active buffer priority in which the buffer receiving the cells belonging to the packet under consideration is defined as the active buffer and is given priority. In the proposed scheme, the queue length is reduced by giving the priority to the active buffer, and efficient switching is realized. The packet loss probability and the average packet delay are evaluated by computer simulation. It is found that the proposed scheme can greatly improve the packet loss probability compared to the conventional scheme, with degradation of the average packet delay by approximately 20 slots. It is also shown that a satisfactory loss probability is realized even if the buffer size is small, and that good expandability with regard to the switch size is achieved. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 79–90, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10120
Performance evaluation of mobile ad hoc routing protocols based on link expiration time and load of node
Authors: Hakoda Jun‐ichi , Uehara Hideyuki , Yokoyama Mitsuo
Published: October 2003

In mobile ad hoc networks, performance is degraded by link breakage due to node mobility and packet collision due to network congestion. Therefore, it is very attractive to investigate routing protocols which use a routing metric to discover long‐lived routes or to disperse network congestion instead of using hopwise shortest routes. In this paper, we examine three route selection schemes in a routing protocol which uses the link expiration time as a routing criterion. Furthermore, we present the Busy Node Avoidance Routing (BNAR) protocol that employs a busy rate representing the nodal load as a new route selection metric. Computer simulation results show the fundamental performance and effectiveness of routes based on the link state and node state. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 68–78, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10137
MMSE adaptive array antenna with sequential processing
Authors: Ichikawa Yoshihiro , Tomitsuka Koji , Obote Shigeki , Kagoshima Kenichi
Published: October 2003

An important problem of the adaptive array antenna proposed previously in regard to its installation is the increased equipment size. This is because the adaptive array antenna requires as many RF circuits as the number of antenna elements. In this paper, in the case where there is an input in one system, we study an adaptive array antenna with sequential processing (AAA‐SP) in which the MMSE (minimum mean square error) criterion is used to control array weights by means of sequential processing of sampled signal data. Since there is only one input system in this case, it is found that the SINR is degraded due to reduction of correlation among elements if the conventional MMSE criterion is used as the adaptive control algorithm. Hence, in order to improve the deterioration of the SINR, a tapped‐delay‐line adaptive array antenna with sequential processing (TDL‐AAA‐SP) is proposed in which oversampling and a TDL‐AAA are combined. It is theoretically proven that the TDL‐AAA‐SP improves the SINR by recovering from reduction of correlation by means of correlation on the time axis. A computer simulation demonstrates that the proposed scheme is effective. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 59–67, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10142
Measuring the sense of reality produced by highly realistic surround display systems: Application of an ARX model to observers' body‐sway data
Authors: Ohnishi Hitoshi , Mochizuki Kaname , Sugimoto Yuji Y.
Published: October 2003

We propose a quantitative method of evaluating observers' perceptions, that is, “feeling of immersion,” when a visual stimulus is displayed on a surround display. The proposed method uses the movement of an observer's center of gravity induced by a visual stimulus as an index. To analyze the quantitative relationship between body sway and visual stimuli, an ARX model was fitted to data obtained by measuring observers' body sway when a visual stimulus was displayed on surround displays. The results showed that adding horizontal screens increased the observers' body sway, whereas vertical screens did not when the visual stimulus moved in a rolling fashion. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 46–58, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10150
Performance of an adaptive predistorted power amplifier with peak limited baseband code‐division multiplexed signal
Authors: Mizuta Shinji , Kawaguchi Hiroko , Akaiwa Yoshihiko
Published: October 2003

In FDM and CDM systems, the peak‐to‐average power ratio (PAPR) increases as the number of signals to be multiplexed is increased. When a signal with a large PAPR is incident on a power amplifier, either the out‐of‐band radiation is increased or the power efficiency is degraded. Methods of resolving these problems are nonlinear distortion compensation techniques, one of which is the predistorter. Another conceivable solution is to suppress the PAPR of the input signal. In this paper, we first study the performance when a limiter is used for the CDM signal in the baseband. By computer simulation, it is shown that the PAPR is suppressed by using a limiter and that the deterioration of the SIR performance is small if the PAPR is more than 6 dB. Next, the characteristics are studied by numerical simulation when a CDM signal with a limiter in the baseband is input to an adaptive predistorter‐type distortion‐compensated power amplifier. By combining the CDM signal with a limiter in the baseband and the adaptive predistorter‐type distortion‐compensated power amplifier, it is possible to suppress the out‐of‐band radiated power and simultaneously increase the power efficiency. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 37–45, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10154
Characteristics of T‐type monopole antenna with parallel resonance mode
Authors: Sekine Syu‐ichi , Shoki Hiroki
Published: October 2003

Use of dipole antennas for portable wireless transceivers has been attempted. In order to realize this application, it is necessary to add a matching network and a balun or a folded configuration. Hence, integration is found difficult. In this paper, a T‐type monopole antenna with a parallel resonance mode is proposed. It is shown by simulation and measurement with a 2‐GHz handset model that this antenna does not require any balun, is capable of self‐matching, and can suppress unwanted radiation from the case as for a dipole antenna. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 28–36, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10157
Service specification description method for advanced intelligent network
Authors: Okamoto Mitsuhiro , Niitsu Yoshihiro
Published: October 2003

The communication service software (SLP) which realizes the communication service in advanced IN is usually generated automatically through a description of the service specification in a diagram format in the service generation environment (SCE). This paper considers such a description of the service specification in diagram format for SLP generation, and proposes a method of service specification description which allows easier description, is easier to understand, and has greater descriptive capability than the conventional description method. A widely used conventional description is the method proposed in ITU‐T, in which the descriptive elements (having the role of icons) correspond one‐to‐one to the service‐independent building blocks (SIBs). It sometimes happens, however, that the SIB as a functional unit is too large, degrading the reusability and understandability of the service specification. In contrast, the proposed description method is based on the information sequence diagram previously proposed by the authors, and extends the descriptive capability by adding descriptive elements so that the service specification of advanced IN can be described. The proposed description method was evaluated by nonexpert examinees, and it was verified that the description is easy and understandable. The proposed description method is also applied to SLP description of many commercial services, and it is verified that the necessary descriptive capability is provided. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 17–27, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10162
Coaxial feed‐type microstrip patch antenna with variable antenna height
Authors: Kitatani Kazuhiro , Yamamoto Sadahiko
Published: October 2003

This paper describes a functional antenna with variable antenna height in which the coaxial feed section of the microstrip patch antenna is engineered. This is a new type of antenna combining mechatronic technology and the microstrip antenna so that the resonant frequency of the antenna can be varied by mechanical adjustment of the antenna height. In addition, since the patch can be rotated, the plane of polarization can also be rotated. This antenna has these two functionalities. In this paper, a simple theoretical investigation is carried out on the resonant frequency of the antenna. Further, the experimental results of the test antenna using a conventional dielectric substrate are presented. In the X band, the resonant frequency of the patch antenna can be varied by about 10% when the antenna height is changed by 0.3 mm. Larger variations of the resonant frequency are expected if high‐permittivity materials such as alumina are used as the substrate. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 10–16, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10173
Permeable wave absorber
Authors: Nakamura Takashi , Ichikawa Takeshi , Sato Risaburo
Published: October 2003

In this paper, a new type of wave absorber permitting transmission is proposed. This absorber has a simple configuration consisting of a resistive film attached to the location where a metal backing is placed in an ordinary absorber. Allowance for transmitted waves and use of a lossless dielectric layer are the unique features. In contrast to the conventional wave absorber, a new degree of freedom is added to the structure and characteristics. By means of equivalent circuit analysis, the reflection and transmission coefficients of the present wave absorber are derived. The nonreflection condition is derived by taking into account the region behind the wave absorber. Based on this derivation, a wave absorber is designed and various characteristics are calculated. The validity of the theoretical results is confirmed by experiment. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 1–9, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10174
Delay difference between tracking loops of different types or TL with various bandwidths of C/A code in GPS
Authors: Tachita Ryobun , Yasuda Akio
Published: October 2003

In GPS positioning by code timing, the accuracy of the basic stand‐alone positioning based only on information broadcast from GPS satellites is approximately 10 m (2 drms). But in GPS utilizing the results of observation by a reference station, the error due to the satellite and the channel can be eliminated, resulting in a positioning accuracy of 1 m (2 drms) or less. In applications in which high accuracy is required, although not as high as in carrier positioning, but in which the satellite signal is often interrupted, it is effective to use DGPS based on code timing. In DGPS based on code timing, the information acquired by a single reference station can be utilized by many rover stations. Different trackers are used in the reference and rover stations. This paper considers the DLL (delay lock loop) system, which is widely used in code tracking, and the SCELL (sampled code edge locked loop) system, with different characteristics. The differential error between the reference and rover stations which is caused by the difference in the receiver bandwidth, the satellite transmission bandwidth, and the difference in code numbers, is analyzed. It is shown that by widening the tracker bandwidth, the error is made sufficiently small compared to that obtained in ordinary DGPS. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 91–98, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1186
Short proofs of classical theorems
Authors: Bondy J. A.
Published: October 2003

We give proofs of Ore's theorem on Hamilton circuits, Brooks' theorem on vertex coloring, and Vizing's theorem on edge coloring, as well as the Chvátal‐Lovász theorem on semi‐kernels, a theorem of Lu on spanning arborescences of tournaments, and a theorem of Gutin on diameters of orientations of graphs. These proofs, while not radically different from existing ones, are perhaps simpler and more natural. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 159–165, 2003
A list analogue of equitable coloring
Authors: Kostochka A. V. , Pelsmajer M. J. , West D. B.
Published: October 2003

Given lists of available colors assigned to the vertices of a graph G, a list coloring is a proper coloring of G such that the color on each vertex is chosen from its list. If the lists all have size k, then a list coloring is equitable if each color appears on at most $\lceil n (G)/k \rceil$ vertices. A graph is equitably k‐choosable if such a coloring exists whenever the lists all have size k. We prove that G is equitably k‐choosable when $k \ge {\rm max} \{ {\Delta (G),n(G)/2}\}$ unless G contains $K_{k+1}$ or k is odd and $G=K_{k,k}$. For forests, the threshold improves to $k \ge 1+\Delta (G)/2$. If G is a 2‐degenerate graph (given k ≥ 5) or a connected interval graph (other than $K_{k+1}$), then G is equitably k‐choosable when $k\ge \Delta(G)$. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 166–177, 2003
Critical groups for complete multipartite graphs and Cartesian products of complete graphs
Authors: Jacobson Brian , Niedermaier Andrew , Reiner Victor
Published: October 2003

The critical group of a connected graph is a finite abelian group, whose order is the number of spanning trees in the graph, and which is closely related to the graph Laplacian. Its group structure has been determined for relatively few classes of graphs, e.g., complete graphs and complete bipartite graphs. For complete multipartite graphs $K_{n_{1},\ldots, {n_k}}$, we describe the critical group structure completely. For Cartesian products of complete graphs $K_{n_{1}} \times \cdots \times K_{n_{k}}$, we generalize results of H. Bai on the k‐dimensional cube, by bounding the number of invariant factors in the critical group, and describing completely its p‐primary structure for all primes p that divide none of $n_1, \ldots, n_k$. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 231–250, 2003
Steiner type problems for digraphs that are locally semicomplete or extended semicomplete
Authors: Bang‐Jensen Jørgen , Gutin Gregory , Yeo Anders
Published: October 2003

We consider the following three problems: (P1) LetDbe a strong digraph and letXbe a non‐empty subset of its vertices. Find a strong subdigraphD′ ofDwhich contains all vertices ofXand has as few arcs as possible. This problem is also known under the name the directed Steiner problem. (P2) LetDbe a strong digraph with real‐valued costs on the vertices. Find a strong subdigraph ofDof minimum cost. (P3) LetDbe a strong digraph with real‐valued costs on the vertices. Find a cycle of minimum cost inD. All three problems are NP‐hard for general digraphs. The second problem generalizes the problem of finding a smallest strong subdigraph (measured in the number of vertices) which covers a given non‐empty setXof vertices. We describe polynomial algorithms for the problems (P1) and (P2) in the case whenDis either locally semicomplete or extended semicomplete and for (P3) in the case of locally semicomplete digraphs. A polynomial algorithm for (P3) in the case of extended semicomplete digraphs was given by Bang‐Jensen et al.,2002. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 193–207, 2003
Hamilton decompositions of complete multipartite graphs with any 2‐factor leave
Authors: Leach C. D. , Rodger C. A.
Published: October 2003

For m ≥ 1 and p ≥ 2, given a set of integers s1,…,sq with $s_j \geq p+1$ for $1 \leq j \leq q$ and ${\sum _{j\,=\,1}^q} s_j = mp$, necessary and sufficient conditions are found for the existence of a hamilton decomposition of the complete p‐partite graph $K_{m,\ldots,m} - E(U)$, where U is a 2‐factor of $K_{m,\ldots,m}$ consisting of q cycles, the jth cycle having length sj. This result is then used to completely solve the problem when p = 3, removing the condition that $s_j\ge p+1$. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 208–214, 2003
On a conjecture of Brualdi and Shen on block transitive tournaments
Authors: Acosta P. , Bassa A. , Chaikin A. , Riehl A. , Tingstad A. , Zhao L. , Kleitman D. J.
Published: October 2003

The following conjecture of Brualdi and Shen is proven in this paper: let n be partitioned into natural numbers no one of which is greater than (n + 1) / 2. Then, given any sequence of wins for the players of some tournament among n players, there is a partition of the players into blocks with cardinalities given by those numbers, and a tournament with the given sequence of wins, that is transitive on the players within each block. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 215–230, 2003
Self‐clique graphs and matrix permutations
Authors: Bondy Adrian , Durán Guillermo , Lin Min Chih , Szwarcfiter Jayme L.
Published: October 2003

The clique graph of a graph is the intersection graph of its (maximal) cliques. A graph is self‐clique when it is isomorphic with its clique graph, and is clique‐Helly when its cliques satisfy the Helly property. We prove that a graph is clique‐Helly and self‐clique if and only if it admits a quasi‐symmetric clique matrix, that is, a clique matrix whose families of row and column vectors are identical. We also give a characterization of such graphs in terms of vertex‐clique duality. We describe new classes of self‐clique and 2‐self‐clique graphs. Further, we consider some problems on permuted matrices (matrices obtained by permuting the rows and/or columns of a given matrix). We prove that deciding whether a (0,1)‐matrix admits a symmetric (quasi‐symmetric) permuted matrix is graph (hypergraph) isomorphism complete. © 2003 Wiley Periodicals, Inc. J Graph Theory 44: 178–192, 2003
If only I hadn't smoked: The impact of counterfactual thinking on a smoking‐related behavior
Authors: Page Christine M. , Colby Patricia M.
Published: October 2003

The role of counterfactual thinking as an effective antismoking communications strategy is examined. Specifically, this study investigates how various types of counterfactual thoughts, generated in response to a detrimental smoking scenario, impact individuals' affective evaluations of the scenario, as well as their willingness to participate in a smoking‐related behavioral test, a lung‐capacity test. This is tested in three experiments, which differ in the timing of gathering individuals' willingness to participate in the lung‐capacity test. Experiment 1 collected individuals' willingness to participate in the test shortly after the counterfactual task, whereas Experiments 2 and 3 made this assessment 2 and 7 days following the counterfactual task (respectively). The results of all three experiments indicated that although upward counterfactuals had a negative impact on individuals' affective evaluations of the scenario, they had no effect on participants' willingness to schedule a lung‐ capacity test. Alternatively, additive counterfactuals did have a significant impact on individuals' preparative actions, despite having no influence on their affective evaluations. This effect, however, decreased with time. By demonstrating that counterfactual thinking may significantly influence smoking‐related behaviors, this study's findings contribute to and extend prior counterfactual and antismoking research. © 2003 Wiley Periodicals, Inc.
The relationship between product involvement and product knowledge: Moderating roles of product type and product knowledge type
Authors: Park Chan‐Wook , Moon Byeong‐Joon
Published: October 2003

To shed further light on the correlation between consumer product involvement and consumer product knowledge, the authors examined such correlation by treating product type and product knowledge type as moderating variables. The results show that the correlation between a consumer's product involvement and objective product knowledge is higher in a utilitarian product than in a hedonic product. On the contrary, the correlation between a consumer's product involvement and subjective product knowledge is higher in a hedonic product than in a utilitarian product. The implications of these results are discussed. © 2003 Wiley Periodicals, Inc.
Dueling or the battle royale? The impact of task complexity on the evaluation of entry threat
Authors: Klemz Bruce R. , Gruca Thomas S.
Published: October 2003

Current marketing research on response to entry assumes that an incumbent decision maker faces potential rivals one at a time as in a series of duels. In many circumstances, however, an incumbent decision maker faces a large number of entrants simultaneously (a “battle royale”). An experiment using experienced managers shows that the increased complexity produced by multiple entrants had a significant effect on the managers' decision processes and their decision outcomes. Specifically, when faced with multiple entrants, the managers adopted more noncompensatory decision processes, and were more likely to misidentify the most threatening entrant as defined by their self‐explicated weights or conjoint part‐worths. These results provide insight into an unexplained gap between the extant normative and empirical research on response to entry. © 2003 Wiley Periodicals, Inc.
“I know this brand, but did I like the ad?” An investigation of the familiarity‐based sleeper effect
Authors: Pashupati Kartik
Published: October 2003

An experiment was designed to investigate the existence of the familiarity‐based sleeper effect proposed by Moore and Hutchinson (1983, 1985). The study also investigated the effects of advertisement repetition on the relationship between attitude toward the ad (Aad) and attitude toward the brand (Ab). Television commercials, embedded in a 30‐min television program, were used as stimuli. A between‐subjects factorial design was used, with 12 cells: three ad types (positive, neutral, and negative), two repetition levels (one versus three exposures to the test commercial) and two delay conditions (Ab was measured either immediately after exposure or 7 days later). The data do not support the existence of a sleeper effect, and provide limited support for the other hypotheses proposed in the study. © 2003 Wiley Periodicals, Inc.
The effect of supply chain glitches on shareholder wealth
Authors: Hendricks Kevin B. , Singhal Vinod R.
Published: October 2003

This paper estimates the shareholder wealth affects of supply chain glitches that resulted in production or shipment delays. The results are based on a sample of 519 glitches announcements made during 1989–2000. Shareholder wealth affects are estimated by computing the abnormal stock returns (actual returns adjusted for industry and market‐wide influences) around the date when information about glitches is publicly announced. Supply chain glitch announcements are associated with an abnormal decrease in shareholder value of 10.28%. Regression analysis is used to identify factors that influence the direction and magnitude of the change in the stock market’s reaction to glitches. We find that larger firms experience a less negative market reaction, and firms with higher growth prospects experience a more negative reaction. There is no difference between the stock market’s reaction to pre‐1995 and post‐1995 glitches, suggesting that the market has always viewed glitches unfavorably. Capital structure (debt–equity ratio) has little impact on the stock market’s reaction to glitches. We also provide descriptive results on how sources of responsibility and reasons for glitches affect shareholder wealth.
Endochondral ossification in fracture callus during long bone repair: The localisation of ‘cavity‐lining cells’ within the cartilage
Authors: Ford Joanna L. , Robinson Derek E. , Scammell Brigitte E.
Published: October 2003

Successful fracture healing typically involves the production of a cartilaginous callus, which is eventually remodelled into new bone. The blood vessels in the advancing front of endochondral ossification are likely to play an important role in the replacement of cartilage with bone within the callus. This was investigated by histology and immunohistochemistry techniques carried out on rabbit tibial osteotomy tissue. Cavities within the cartilage were identified by histology and in many cases, there appeared to be vascular structures within them, identified by the immunolocalisation of the transmembrane proteins CD31 and CD34. Osteocalcin localisation and Alizarin red histology was carried out to identify ‘osteoblastic’ cells and mineral localisation within the cartilaginous callus respectively.

However, it was the identification of a population of cells lining the cavities within the cartilage that became the main focus of this study. These cells were ‘osteoblastic’ in nature, (positive localisation of osteocalcin), and were also positive for the adhesion proteins CD31 and CD34. It is thought that these cells play a role in the conversion of cartilage to bone during the fracture healing process. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
The effectiveness of polyethylene versus titanium particles in inducing osteolysis in vivo
Authors: von Knoch Marius , Jewison Donna E. , Sibonga Jean D. , Sprecher Christoph , Morrey Bernard F. , Loer Franz , Berry Daniel J. , Scully Sean P.
Published: October 2003

Bearing surface wear and periprosthetic osteolysis due to wear particles are among the most common reasons for joint replacement failure. A murine calvarial model of wear particle‐induced osteolysis has been used to identify different biologic factors associated with this problem and to test nonsurgical methods of modulating the host response to particulate debris. This model has utilized titanium particles, however, in clinical practice the most common source of particulate debris is polyethylene particles from bearing surface wear. We now report a calvarial model of wear particle‐induced osteolysis based on commercially available polyethylene particles. We found that compared to sham surgery osteoclast recruitment and bone resorption can be induced by introduction of the titanium particles or polyethylene particles. However, bone resorption was significantly higher with polyethylene particles compared to titanium particles (p = 0.02).

We consider the polyethylene based murine calvarial model of wear particle‐induced osteolysis a reliable and clinically relevant tool to understand the host factors and potential pharmacologic interventions that can influence wear debris generated osteolysis. This model might serve as an extension of the well‐established titanium based bone resorption model. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
A three‐dimensional MRI analysis of knee kinematics
Authors: Patel Vikas V. , Hall Katherine , Ries Michael , Lotz Jeff , Ozhinsky Eugene , Lindsey Colleen , Lu Ying , Majumdar Sharmila
Published: October 2003

Purpose: To quantify normal, in vivo tibio‐femoral knee joint kinematics in multiple weight bearing positions using non‐invasive, high‐resolution MRI and discuss the potential of developing future kinematic methods to assess patients with abnormal joint pathologies.

Methods: Ten volunteers with clinically normal knees pushed inferiorly on the footplate of a weight bearing apparatus inside the MR scanner. The volunteers held the weight (133 N) for five scans as the knee motion was evaluated from 0° to 60° of flexion. Full extension was set as the zero point for all measured parameters. Using 3D reconstructions, tibia motion relative to the femur and flexion angle was measured as varus–valgus angle, axial rotation, anterior–posterior translation, and medial–lateral translation. Medial and lateral compartment tibio‐femoral contact areas were examined and centroids of the contract areas were calculated.

Results: Tibial internal rotation averaged 4.8° at 40° of flexion and then decreased. Tibial valgus increased by 8° at 60° of flexion. Femoral roll back also increased to 18.5 mm average at 60° of flexion, while the tibia translated medially 2.5 mm. Medial compartment femoro‐tibial contact area started at 374 mm2 and decreased to 308 mm2 with flexion of 60°, while lateral compartment contact area did not change significantly from 276 mm2.

Conclusions: Results correlate with previous studies of knee kinematics while providing greater three‐dimensional detail. MR imaging allows excellent non‐invasive evaluation of knee joint kinematics with weight bearing. This tool may potentially be used for assessing knee kinematics in patients with knee pathology. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Differential lipid affinity of xenobiotics and natural compounds
Authors: Sandermann Heinrich
Published: October 2003

Octanol‐1/water partitioning currently provides the most widely used model system to simulate both phospholipid target lipids and triglyceride storage lipids. A differentiation between the two lipid classes is now achieved by making use of a water‐induced lipid phase separation. Coefficients (K
TG/PC) for partitioning between trioleoylglycerol (TG) and phosphatidylcholine (PC) were determined for 20 xenobiotics and two biological lipids. K
TG/PC values are related to K
OW through the relationship, log K
TG/PC=0.33 log K
OW−1.078. The present results will allow better predictions on whether drugs and xenobiotics are bioaccumulated, degraded or reach toxicity‐related sites. In addition, applications to natural lipophilic compounds and disease‐related proteins are discussed.
The Wilms’ tumour suppressor protein, WT1, undergoes CRM1‐independent nucleocytoplasmic shuttling
Authors: Vajjhala P.R , Macmillan E , Gonda T , Little M
Published: October 2003

The Wilms’ tumour suppressor gene (WT1) encodes a zinc finger‐containing nuclear protein essential for kidney and urogenital development. Initially considered a transcription factor, there is mounting evidence that WT1 has a role in post‐transcriptional processing. Using the interspecies heterokaryon assay, we have demonstrated that WT1 can undergo nucleocytoplasmic shuttling. We have also mapped the region responsible for nuclear export to residues 182–324. Our data add further complexity to the role of WT1 in trancriptional and post‐transcriptional regulation.
The Politics of the Minimum Wage. By Jerold Waltman. Urbana: University of Illinois Press, 2000. 172p. $24.95.
Authors: Daynes Byron W.
Published: October 2003

Upon receiving Jerald Waltman's book, the first thing I read
was the dedication to the author's "coworkers at A. & W.
Root Beer, Ruston, Louisiana, 1963­67." I like root beer, but
I wondered whether a mistake had been made in sending me
this book to review. It did not take long to realize no mistake
had been made. This is a book that treats minimum wage as
symbolic politics, but, more important, it entirely reexamines
public policy.
Incentives and Institutions: The Transition to a Market Economy in Russia. By Serguey Braguinsky and Grigory Yavlinsky. Princeton, NJ: Princeton University Press, 2000. 282p. $39.50.
Authors: Wegren Stephen
Published: October 2003

After a decade of market reforms, it is obvious to most
observers that something has gone wrong in Russia. Some
economic indicators suggest modest successes in instituting a
market economy, but most of the evidence is clear that the
economic and social crisis has far exceeded what might be
expected in terms of a "transformation recession." Industrial
and agricultural output is down substantially, capital renewal
is not keeping pace with the retirement of old machinery, the
nation is deindustrializing, real living standards have plum-
meted, and investment capital is fleeing the country. The
authors of this book conclude that "the Russian privatization
program was nothing but a grandiose failure" (p. 6).
ANALYTIC–NUMERICAL SOLUTIONS WITH A PRIORI BOUNDS FOR MATRIX–VECTOR PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS
Authors: Jódar Lucas , Marletta Marco
Published: October 2003

We consider a parabolic matrix–vector system in which the diffusion matrix may be time dependent. For the time-independent case we construct approximate solutions with guaranteed error bounds using spectral information from certain matrix–vector Sturm–Liouville problems. For the time-dependent case we employ an approximation procedure which reduces the problem, on each time-step, to the time-independent case. We give an algorithm which may be used a priori at each time-step in the time-dependent case to guarantee accuracy to a specified tolerance.

AMS 2000 Mathematics subject classification: Primary 35C10; 35M10. Secondary 15A