bluuebunny/crossref_metadata_2025 huggingface dataset:
On the dyadic Green's function in the source region embedded in waveguides or cavities filled with a stratified medium
Authors: Słobodzian Piotr M.
Published: October 2002

A relatively simple method of derivation of the Green's function for vertical current sources embedded in uniform waveguides has been described. The question of singularity of the electric dyadic Green's function in the source region has been discussed, and an appropriate form of the singular component, as regards the numerical treatment, has been derived and validated. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 93–97, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10526
Determination of complex permittivity and thickness of a single‐layer material using reflection ellipsometry at several angles of incidence
Authors: Sagnard F.
Published: October 2002

An analytic formulation is proposed to obtain both complex permittivity and thickness of a single‐layer material from reflection ellipsometry data obtained at more than two angles of incidence. The principle consists in decoupling the equations that involve both thickness and complex permittivity. The solution is based on multi‐steps numerical processing methods. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 154–157, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10544
Design and fabrication of a single‐ended gate mixer for a down‐converter in wireless applications
Authors: Yang Dooyeong , Chung You Chung
Published: October 2002

A single‐ended gate mixer with a high conversion gain, low dissipated power, wide dynamic range and good isolation factor is designed and tested. The mixer is composed of a hairpin‐line band‐pass filter, an input/output matching circuit, a GaAs MESFET transistor, and a lumped element low‐pass filter to convert the radio frequency (RF) into an intermediate frequency (IF). In the non‐linearity analysis of a GaAs MESFET, the novel method with a harmonic balance technique is used to analyze the operating characteristics of a mixer circuit. The designed mixer outperforms a general mixer for a down converter in wireless applications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 189–193, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10553
Wide band rectangular microstrip antenna using symmetric T‐shaped feed
Authors: Menon Sreedevi K. , Lethakumary B. , Vasudevan K. , Mohanan P.
Published: October 2002

Bandwidth enhancement of a rectangular microstrip antenna using a T‐shaped microstrip feed is explored in this paper. A 2:1 VSWR impedance bandwidth of 23% is achieved by employing this technique. The far‐field patterns are stable across the pass band. The proposed antenna can be used conveniently in broadband communications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 235–236, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10566
2D NMR analysis for unambiguous structural elucidation of phenolic compounds formed through reaction between (+)‐catechin and glyoxylic acid
Authors: Es‐Safi Nour‐Eddine , Le Guernevé Christine , Cheynier Véronique , Moutounet Michel
Published: October 2002

Various phenolic compounds were synthesized in an aqueous–alcoholic solution containing (+)‐catechin and glyoxylic acid which was used as a model of fruit‐derived food browning that usually occurs during aging. After purification by semi‐preparative HPLC, the isolated compounds were subjected to homo‐ and heteronuclear proton and carbon NMR analysis including COSY, TOCSY, ROESY, HSQC and HMBC techniques. These experiments allowed the structural elucidation and complete 1H and 13C NMR assignment of the isolated compounds. The strategies followed for the assignment of all proton and carbon resonances in addition to the linkage site determination are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
NMR studies on 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(4‐aminophenoxy)‐4‐phenyl]‐(2H)phthalazin‐1‐one
Authors: Wang Tianzhi , Cheng Lin , Zhang Tao , Yuan Hanzhen , Mao Shizhen
Published: October 2002

An unsymmetrical heterocyclic diamine, 1,2‐dihydro‐2‐(4‐aminophenyl)‐4‐[4‐(4‐aminophenoxy)‐4‐phenyl]‐(2H)phthalazin‐1‐one, was synthesized. Its 1H and 13C NMR spectra were completely assigned by utilizing the two‐dimensional heteronuclear 13C–1H multiple‐bond coherence (HMBC) spectroscopy, and heteronuclear 13C–1H one‐bond correlation spectroscopy, homonuclear shift correlation spectroscopy (H,H‐COSY) and rotating frame Overhauser enhancement spectroscopy (ROESY). The structure of the compound was shown to be the phthalazinone rather than the phthalazine ether from cross peaks and chemical shifts of the protons. Copyright © 2002 John Wiley & Sons, Ltd.
A 13C NMR study of the methylol derivatives of 2,4′‐ and 4,4′‐dihydroxydiphenylmethanes found in resol phenol–formaldehyde resins
Authors: Fisher Thomas H. , Chao Ping , Upton Cindy G. , Day Anthony J.
Published: October 2002

A total of 13 of the 16 possible methylol derivatives of 2,4′‐ and 4,4′‐dihydroxydiphenylmethane have been synthesized, isolated, and identified. These compounds are found as intermediates in the cure process of resol phenol–formaldehyde (PF) resins. Analysis of the 13C NMR spectra (in acetone‐d6) of these compounds provided a way to evaluate the seven methylolphenol ring types (methylol derivatives of 2‐hydroxyphenyl and 4‐hydroxyphenyl rings) found in typical resol PF resins using the ipso carbon region from 150 to 160 ppm. A simple diagnostic test was developed using the chemical shift values of the methylol methylene carbon atoms to identify the presence of intermediates containing either a 2‐hydroxyphenyl or a 4‐hydroxyphenyl ring. Using these data it is now possible to analyze the major components in extracted prepreg PF resins. Copyright © 2002 John Wiley & Sons, Ltd.
1H, 13C, and 15N NMR analysis of Tröger's base and of some of its [15N1] labelled precursors
Authors: Salort Francisca , Pardo Carmen , Elguero José
Published: October 2002

One‐ and two‐dimensional NMR spectra of Tröger's base, (±)‐2,8‐dimethyl‐6H,12H‐5,11‐methanodibenzo[b,f][1,5]diazocine labelled on one of the nitrogen atoms, have been used to determine the chemical shifts, coupling constants, and Δ13C(15N) isotope shifts. Copyright © 2002 John Wiley & Sons, Ltd.
Valosine containing protein is a substrate of cAMP—Activated boar sperm tyrosine kinase
Authors: Geussova Gizela , Kalab Petr , Peknicova Jana
Published: October 2002

Previously we reported that treatment of boar sperm with cAMP‐elevating drugs induces tyrosine phosphorylation of a triton‐insoluble 93 kDa protein (p93). We have isolated p93 by preparative SDS electrophoresis and blotting from urea‐extracted boar sperm and identified it as a valosine containing protein (VCP) by mass spectrometry and microsequencing. With the use of antibodies to VCP and phosphotyrosine (pY) we found that both p93 and VCP are poorly extractable with triton and are solubilized in > 6 M urea. Furthermore, VCP and p93 overlap on one and two dimensional (1 and 2D) electrophoretic gels, supporting the identity of p93 as a tyrosine‐phosphorylated population of VCP. According to immunofluorescence, VCP is localized along the entire sperm tail, in the posterior ring, distal equatorial segment, and postacrosome. In addition, 9–12% sperm contained VCP in the acrosome. The cAMP‐elevating treatment did not alter VCP localization but induced tail tyrosine phosphorylation in 15% sperm cells. In those sperm, VCP and pY colocalized in connecting piece and posterior ring. Mol. Reprod. Dev. 63: 366–375, 2002. © 2002 Wiley‐Liss, Inc.
Aberrant methylation patterns at the two‐cell stage as an indicator of early developmental failure
Authors: Shi W. , Haaf T.
Published: October 2002

The fertilized mouse egg actively demethylates the paternal genome within a few hours after fertilization, whereas the maternal genome is only passively demethylated by a replication‐dependent mechanism after the two‐cell stage. This evolutionarily conserved assymetry in the early diploid mammalian embryo may have a role in methylation reprogramming of the two very different sets of sperm and egg chromatin for somatic development and formation of totipotent cells. Immunofluorescence staining with an antibody against 5‐methylcytosine (MeC) showed that the incidence of abnormal methylation patterns differs between mouse two‐cell embryos from superovulated females, nonsuperovulated matings, and in vitro fertilization (IVF). It also depends on embryo culture conditions and genetic background. In general, there was a good correlation with the number of embryos (from the same experiment) which did not develop in vitro up to the blastocyst stage. Thus, aberrant genome‐wide DNA methylation in early embryos may be an important mechanism contributing to the high incidence of developmental failure in mammals. Similar to the situation in abnormally methylated embryos from nuclear transfer, it may cause a high incidence of pregnancy loss and abnormal phenotypes. Mol. Reprod. Dev. 63: 329–334, 2002. © 2002 Wiley‐Liss, Inc.
Imaging cortical anatomy by high‐resolution MR at 3.0T: Detection of the stripe of Gennari in visual area 17
Authors: Barbier Emmanuel L. , Marrett Sean , Danek Adrian , Vortmeyer Alexander , van Gelderen Peter , Duyn Jeff , Bandettini Peter , Grafman Jordan , Koretsky Alan P.
Published: October 2002

The brain can be parcellated into numerous anatomical and functional subunits. The classic work by Brodmann (Vergleichende Lokalisationslehre der Grosshirnrinde in ihren Prinzipien dargestellt auf Grund des Zellenbaues. Leipzig: Barth; 1909) identified areas of the cerebral cortex based on histological differences. An alternative to his cytoarchitectonic approach is the myeloarchitectonic approach. MRI has excellent white/gray matter contrast in the brain due to the presence of myelin, and thus seems uniquely suited for in vivo studies of cortical myeloarchitecture. Here it is demonstrated that the stripe or stria of Gennari can be consistently detected in human occipital cortex.T1‐weighted images obtained at 3T from six of 10 normal volunteers, with resolutions of 350 × 350 × 600 μ, clearly demonstrate this myelin‐rich intracortical layer. It is concluded that the striate cortex (area 17 of Brodmann) of the human brain can be delineated in vivo onT1‐weighted images, potentially enabling detection of specific cortical boundaries within individual brains. Magn Reson Med 48:735–738, 2002. Published 2002 Wiley‐Liss, Inc.
GABA X2 multiplet measured pre‐ and post‐administration of vigabatrin in human brain
Authors: Hanstock Christopher C. , Coupland Nicholas J. , Allen Peter S.
Published: October 2002

This work demonstrates, in solution and in human brain at 3 tesla, that the X2‐multiplet of the A2M2X2 proton spin system of GABA at 2.315 ppm can be readily resolved from that of the overlapping background, particularly the glutamate multiplet, i.e., the PQ multiplet of the glutamate AMNPQ spin system. Prior to experiment, the values of the stimulated echo acquisition mode (STEAM) sequence parameters TE and TM that maximized the GABA‐X2 discrimination from its background (i.e., 168 ms and 28 ms, respectively) were determined numerically. The determination was made by calculating the spectral response of all contributing metabolites to the STEAM sequence throughout TE/TM space. A baseline GABA concentration (mean ± standard deviation (SD) of the mean) of 0.78 ± 0.04 mM was estimated from spectra acquired from a 3 × 3 × 3 cm3 volume in the parieto‐occipital cortex of eight normal control subjects. Five of the eight control subjects were also studied 24 hr post‐administration of a single dose of 50 mg.kg–1 vigabatrin. Four of the five showed increases in GABA in the range of 15–120% of their baseline level. Magn Reson Med 48:617–623, 2002. © 2002 Wiley‐Liss, Inc.
Magnetic stimulation of sacral roots for assessing the efferent neuronal pathways of lower urinary tract
Authors: Rodic Biljana , Schläpfer Andri , Curt Armin , Knapp Peter , Dietz Volker , Schurch Brigitte
Published: October 2002

The value of sacral magnetic stimulation (SMS) in neurophysiological evaluation of the sacral efferent pathways of the lower urinary tract was assessed during urodynamic examination in 10 men with chronic suprasacral spinal cord injury (SCI) and in 7 healthy volunteers. Investigated parameters included latency and amplitude of the urodynamic pressure response of the external urethral sphincter and detrusor to different stimulation strengths (50–100%) and single or repetitive (20 and 30 Hz) stimuli. Following SMS, reproducible external urethral sphincter pressure responses (mean latency, 13 ms) were recorded in all subjects. In contrast, a detrusor pressure increase was recorded only in SCI patients after repetitive SMS, with a latency of 1–2 s. This implies the appearance of a polysynaptic spinal reflex due to changes in organization of the sacral micturition reflex after SCI. The method of SMS may be helpful for the evaluation of cases in which urodynamic studies remain inconclusive. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 486–491, 2002
A study of ground‐structure interaction in dynamic plate load testing
Authors: Guzina Bojan B. , Fata Sylvain Nintcheu
Published: October 2002

A mathematical treatment is presented for the forced vertical vibration of a padded annular footing on a layered viscoelastic half‐space. On assuming a depth‐independent stress distribution for the interfacial buffer, the set of triple integral equations stemming from the problem is reduced to a Fredholm integral equation of the second kind. The solution method, which is tailored to capture the stress concentrations beneath footing edges, is highlighted. To cater to small‐scale geophysical applications, the model is used to investigate the near‐field effects of ground‐loading system interaction in dynamic geotechnical and pavement testing. Numerical results indicate that the uniform‐pressure assumption for the contact load between the composite disc and the ground which is customary in dynamic plate load testing may lead to significant errors in the diagnosis of subsurface soil and pavement conditions. Beyond its direct application to non‐intrusive site characterization, the proposed solution can be used in the seismic analysis of a variety of structures involving annular foundation geometries. Copyright © 2002 John Wiley & Sons, Ltd.
Consistent tangent operators for constitutive rate equations
Authors: Fellin Wolfgang , Ostermann Alexander
Published: October 2002

A general approach for obtaining the consistent tangent operator for constitutive rate equations is presented. The rate equations can be solved numerically by the user's favourite time integrator. In order to obtain reliable results, the substepping in integration should be based on a control of the local error. The main ingredient of the consistent tangent operator, namely the derivative of the stress with respect to the strain increment must be computed simultaneously with the same integrator, applied to a numerical approximation of the variational equations. This information enables finite‐element packages to assemble a consistent tangent operator and thus guarantees quadratic convergence of the equilibrium iterations. Several numerical examples with a hypoplastic constitutive law are given. As numerical integrator we used a second‐order extrapolated Euler method. Quadratic convergence of the equilibrium iteration is shown. Copyright © 2002 John Wiley & Sons, Ltd.
Functional analysis of human parotid gland in vivo using the 1H MRS MT effect
Authors: Saito Moyoko , Umeda Masahiro , Fujiwara Kei , Kakimoto Naoya , Tanaka Chuzo , Murakami Shumei , Furukawa Souhei
Published: October 2002

Magnetization transfer (MT) was measured in the parotid gland in vivo by 1H MR spectroscopy in 10 adult volunteers. A comparison was made of stimulated (excess saliva) and resting parotid gland (SPG and RPG, respectively). Following irradiation at an MT pulse of 150 Hz downfield from the water proton signal, signal reductions in SPG and RPG were 83.8 ± 4.7 and 91.4 ± 5.7%, respectively. The larger reduction for SPG indicates that an increase in the amount of water in gland cells for the production of more parotid saliva may lead to greater affinity between the protons adjacent to macromolecules and free water which contributes to the MT effect. Activity in the parotid gland correlates with the effect. This method is useful for diagnosing disorders of parotid gland secretion. Copyright © 2002 John Wiley & Sons, Ltd.
A comparison of the changes in the non‐neuronal cell populations of the superior cervical ganglia following decentralization and axotomy
Authors: Schreiber Rebecca C. , Vaccariello Stacey A. , Boeshore Kristen , Shadiack Annette M. , Zigmond Richard E.
Published: October 2002

Transecting the axons of neurons in the adult superior cervical ganglion (SCG; axotomy) results in the survival of most postganglionic neurons, the influx of circulating monocytes, proliferation of satellite cells, and changes in neuronal gene expression. In contrast, transecting the afferent input to the SCG (decentralization) results in nerve terminal degeneration and elicits a different pattern of gene expression. We examined the effects of decentralization on macrophages in the SCG and compared the results to those previously obtained after axotomy. Monoclonal antibodies were used to identify infiltrating (ED1+) and resident (ED2+) macrophages, as well as macrophages expressing MHC class II molecules (OX6+). Normal ganglia contained ED2+ cells and OX6+ cells, but few infiltrating macrophages. After decentralization, the number of infiltrating ED1+ cells increased in the SCG to a density about twofold greater than that previously seen after axotomy. Both the densities of ED2+ and OX6+ cells were essentially unchanged after decentralization, though a large increase in OX6+ cells occurred after axotomy. Proliferation among the ganglion's total non‐neuronal cell population was examined and found to increase about twofold after decentralization and about fourfold after axotomy. Double‐labeling experiments indicated that some of these proliferating cells were macrophages. After both surgical procedures, the percentage of proliferating ED2+ macrophages increased, while neither procedure altered the proliferation of ED1+ macrophages. Axotomy, though not decentralization, increased the proliferation of OX6+ cells. Future studies must address what role(s) infiltrating and/or resident macrophages play in regions of decentralized and axotomized neurons and, if both are involved, whether they play distinct roles. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 68–79, 2002
Circadian control of neurogenesis
Authors: Goergen Erin M. , Bagay Leslie A. , Rehm Kris , Benton Jeanne L. , Beltz Barbara S.
Published: October 2002

The life‐long addition of new neurons has been documented in many regions of the vertebrate and invertebrate brain, including the hippocampus of mammals (Altman and Das, 1965; Eriksson et al., 1998; Jacobs et al., 2000), song control nuclei of birds (Alvarez‐Buylla et al., 1990), and olfactory pathway of rodents (Lois and Alvarez‐Buylla, 1994), insects (Cayre et al., 1996) and crustaceans (Harzsch and Dawirs, 1996; Sandeman et al., 1998; Harzsch et al., 1999; Schmidt, 2001). The possibility of persistent neurogenesis in the neocortex of primates is also being widely discussed (Gould et al., 1999; Kornack and Rakic, 2001). In these systems, an effort is underway to understand the regulatory mechanisms that control the timing and rate of neurogenesis. Hormonal cycles (Rasika et al., 1994; Harrison et al., 2001), serotonin (Gould, 1999; Brezun and Daszuta, 2000; Beltz et al., 2001), physical activity (Van Praag et al., 1999) and living conditions (Kemperman and Gage, 1999; Sandeman and Sandeman, 2000) influence the rate of neuronal proliferation and survival in a variety of organisms, suggesting that mechanisms controlling life‐long neurogenesis are conserved across a range of vertebrate and invertebrate species. The present article extends these findings by demonstrating circadian control of neurogenesis. Data show a diurnal rhythm of neurogenesis among the olfactory projection neurons in the crustacean brain, with peak proliferation during the hours surrounding dusk, the most active period for lobsters. These data raise the possibility that light‐controlled rhythms are a primary regulator of neuronal proliferation, and that previously‐demonstrated hormonal and activity‐driven influences over neurogenesis may be secondary events in a complex circadian control pathway. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 90–95, 2002
Patterns of neurogenesis in the midbrain of embryonic lobsters differ from proliferation in the insect and the crustacean ventral nerve cord
Authors: Benton Jeanne L. , Beltz Barbara S.
Published: October 2002

Neurogenesis persists throughout life in the olfactory pathway of many decapod crustaceans. However, the relationships between precursor cells and the temporal characteristics of mitotic events in these midbrain regions have not been examined. We have conducted studies aimed at characterizing the sequence of proliferative events that leads to the production of new deutocerebral projection neurons in embryos of the American lobster, Homarus americanus. In vivo bromodeoxyuridine (BrdU) labeling patterns show that three distinct cell types are involved in neurogenesis in this region. Quantitative and temporal analyses suggest that the clearing time for BrdU is 2–3 days in lobster embryos, and that the sequence of proliferative events in the midbrain is significantly different from the stereotypical pattern for the generation of neurons in the ventral nerve cord ganglia of insects and crustaceans. The unusual pattern of proliferation in the crustacean midbrain may be related to the persistence of neurogenesis throughout life in these regions. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 57–67, 2002
Besov regularity of edge singularities for the Poisson equation in polyhedral domains
Authors: Dahlke Stephan
Published: October 2002

This paper is concerned with the regularity of the solutions to the Poisson equation in polyhedral domains Ω contained in R3. Especially, we consider the specific scale Bτα(Lτ(Ω)),1/τ = α/3 + ½, of Besov spaces. The regularity of the variational solution in these Besov spaces determines the order of approximation that can be achieved by adaptive and non‐linear numerical schemes. It is well‐known that in polyhedral domains different types of singularities according to edges and vertices occur. In this paper, we shall primarily be concerned with the Besov regularity of edge singularities. By the usual reduction procedure, these singularity functions are studied in an unfinite cylinder R × ϒ, where ϒ denotes a bounded polygonal domain contained in R2. We show that the singularity functions are much smoother in the specific Besov scale than in the usual L2–Sobolov scale which justifies the use of adaptive schemes. The proofs are based on specific representations of the solutions and on characterizations of Besov spaces by wavelet expansions. Copyright © 2002 John Wiley & Sons, Ltd.
An approach to the connection between subdomains with non‐matching meshes for transient mechanical analysis
Authors: Herry B. , Di Valentin L. , Combescure A.
Published: October 2002

This paper describes a general method for coupling non‐matching linear finite element meshes in transient dynamic analysis. We propose a method based on Schur's dual formulation whose main advantage is to provide equilibrium as well as kinematic continuity throughout the interface. The essence of our work lies in the particular discretization of the space of Lagrange multipliers and in the validation of the method through two‐ and three‐dimensional static calculations as well as two‐dimensional dynamic calculations. An example is also presented and the results are compared to those of the mortar method. Copyright © 2002 John Wiley & Sons, Ltd.
Successive approximation method for non‐linear optimal control problems with application to a container crane problem
Authors: Jaddu Hussein , Vlach Milan
Published: October 2002

A numerical method is proposed to solve a non‐linear optimal control problem with terminal state constraints, inequality state constraints and control saturation constraints. The method solves this problem directly and without employing penalty functions. First, the problem is reformulated, using the quasilinearization and the state parameterization techniques, into a sequence of quadratic programming problems. Then the resulting quadratic programming problems are solved by the active set method. The proposed method is applied to a practical optimal control problem of minimizing the swing angle of a container during its transfer from a ship to a truck. Copyright © 2002 John Wiley & Sons, Ltd.
Book Reviews
Authors: Donahue John D.
Published: October 2002

Negotiating the World Economy, by John S. Odell. Ithaca, NY: Cornell University Press, 2000,
252 pp., $45.00 cloth, $19.95 paper. Reviewed by Daniel J.B. Mitchell

Evaluating Welfare Reform in an Era of Transition, edited by Robert A. Moffitt and Michele Ver
Ploeg. Washington, DC: National Academy Press, 2001, 268 pp., $42.95. Reviewed by Daniel H. Weinberg

Red Tape and Housing Costs: How Regulation Affects New Residential Development, by Michael I.
Luger and Kenneth Temkin. New Brunswick, NJ: Center for Urban Policy Research, 2000, 192 pp., $24.95 cloth.
Reviewed by Thomas Bier

Waste Trading among Rich Nations, by Kate O'Neill. Cambridge, MA: The MIT Press, 2000,
310 pp., $60.00 cloth, $22.00 paper. Reviewed by Lee S. Friedman

Markets for Clean Air, by A. Denny Ellerman, Paul L. Joskow, Richard Schmalensee,
Juan‐Pablo Montero, and Elizabeth M. Bailey. Cambridge, UK: Cambridge University Press, 2000, 352 pp.,
$40.00. Reviewed by Lee S. Friedman

The Collapse of the Kyoto Protocol and the Struggle to Slow Global Warming, by David G.
Victor. Princeton, NJ: Princeton University Press, 2001, 178 pp., $22.95. Reviewed by Robert Falkner

Causes of War: Power and the Roots of Conflict, Stephen Van Evera, Ithaca, NY: Cornell
University Press, 1999, 270 pp., $35.00 cloth, $17.95 paper. Reviewed by Erik Gartzke

Power versus Prudence: Why Nations Forgo Nuclear Weapons, by T. V. Paul. Montreal:
McGill‐Queen's University Press, 2000, 227 pp., $22.95. Reviewed by Leonard S. Spector

The Wealth and Poverty of Nations: Why Some Are So Rich and Some So Poor, by David S. Landes,
New York: W.W. Norton, 1998, 650 pp., $11.87 paper. Reviewed by Eugene B. McGregor, Jr.

The End of the Nation‐state: The Rise of the Regional Economies, by Kenichi Ohmae, New
York: Free Press Paperbacks, 1995, 214 pp., $16.95 paper. Reviewed by Eugene B. McGregor, Jr.

Governance in a Globalizing World, edited by Joseph S. Nye and John D. Donahue, Washington,
DC: Brookings Institution Press, 2000, 386 pp., $18.95 paper. Reviewed by Eugene B. McGregor, Jr.
Barrier property of clay/Acrylonitrile‐butadiene copolymer nanocomposite
Authors: Nah Changwoon , Ryu Hyune Jung , Kim Wan Doo , Choi Sung‐Seen
Published: October 2002

The resistance to air permeation was investigated for ­an intercalated clay/acrylonitrile‐butadiene copolymer ­nanocomposite. The nanocomposite is prepared by melt mixing the organo‐treated montmorillonite into a rubber matrix, together with peroxide curative, and crosslinked by conventional compression molding for typical rubbers. In the case of intercalated nanocomposite, the air permeability decreases considerably with increasing clay content, and the decreasing trend agrees reasonably with the Neilson's tortuous model. No considerable improvement is found when the pure montmorillonite is added. Copyright © 2002 John Wiley & Sons, Ltd.
An overview of developments in poly(urethane‐isocyanurates) elastomers
Authors: Samborska‐Skowron Roksana , Balas Adolf
Published: October 2002

The growth of the science and technology of plastics leads to the development of new materials with more desirable properties. Such kinds of materials include polyurethanes with isocyanurate structural units combining the properties of great strength and high temperature stability. Most of them are produced as rigid foams designed as insulation materials for industrial applications. However, great progress has been made with the introduction of isocyanurate rings in the non‐cellular areas, especially in elastomers. The aim of this work is to present an overview of the major developments on the field of poly(urethane‐isocyanurate) elastomers. Copyright © 2002 John Wiley & Sons, Ltd.
Polymer light‐emitting electrochemical cell based on a block copolymer containing tri(ethyleneoxide) spacers
Authors: Sun Qingjiang , Yang Chunhe , Wang Haiqiao , He Gufeng , Li Yongfang
Published: October 2002

We presented the optical properties of a novel block copolymer containing chromophores, 2,5‐dimethoxy‐1,4‐di(α‐(2‐naphthalene vinylene)benzene (MDNVB) and spacers, tri(ethylene oxide) (TEO). The intrachain and interchain excitations due to the molecular aggregation are responsible for the significant bathochromic shift in the photoluminescence (PL) spectrum when going from the solution to the thin film. With a certain content of the polymer electrolyte, blue–green light‐emitting electrochemical cell based on this block copolymer was demonstrated with the turn‐on voltage of 2.5 V, the maximum electroluminescence (EL) efficiency of 1.2 cd/A, and the d.c. response time of less than 5 sec, indicating strongly that an improved morphology of the active layer is formed because of the effective TEO‐PEO interaction. Lowering the content of the polymer electrolyte results in a higher turn‐on voltage and smaller injection current; increasing the content leads to a considerable microscopic leaking current and lower EL efficiency of the device. Copyright © 2002 John Wiley & Sons, Ltd.
Metalloelastase (MMP‐12) expression by tumour cells in squamous cell carcinoma of the vulva correlates with invasiveness, while that by macrophages predicts better outcome
Authors: Kerkelä Erja , Ala‐aho Risto , Klemi Pekka , Grénman Seija , Shapiro Steven D. , Kähäri Veli‐Matti , Saarialho‐Kere Ulpu
Published: October 2002

Human metalloelastase (MMP‐12) has been implicated in elastin degradation and macrophage migration in many pathological conditions. It also generates angiostatin, thus having a potential to prevent tumour angiogenesis. It has previously been shown that transformed epithelial cells express MMP‐12 in skin cancer. The aim of this study was further to elucidate the role of metalloelastase in squamous cell cancer (SCC) progression. By in situ hybridization, expression of MMP‐12 mRNA was detected in 28/33 vulvar SCC samples in CD‐68‐positive macrophages, while 10 samples had positive cancer cells. By immunohistochemistry, MMP‐12 protein was seen in the same area as the mRNA. MMP‐12 mRNA expression in tumour cells correlated with more aggressive histology (p = 0.0099). In contrast, macrophage‐derived MMP‐12 mRNA was more abundant in well‐differentiated grade I than grade III tumours (p = 0.01). However, the level of MMP‐12 mRNA, regardless of its origin, did not correlate with metastasis or patient survival. No significant correlation was found between macrophage‐derived MMP‐12 mRNA and a low amount of blood vessels, as quantitated after von Willebrand staining. In agreement with vulvar SCCs in vivo, MMP‐12 was expressed in cultured SCC cells by northern and western blot analysis. In HaCaTs and epithelial MCF‐10f cells, MMP‐12 mRNA was induced by transforming growth factor‐β1 (TGF‐β1) and tumour necrosis factor‐α (TNF‐α) as measured by quantitative RT‐PCR (TaqMan). Two MMPs capable of generating angiostatin in vivo, matrilysin (MMP‐7) and gelatinase B (MMP‐9), were also examined in these tumours. MMP‐7 mRNA was mainly expressed by epithelial tumour cells, particularly in less differentiated tumours. MMP‐9 was usually expressed by neutrophils and macrophages; epithelial protein was predominantly found in grade II/III tumours. These results suggest a dual role for MMP‐12 in tumour progression. Copyright © 2002 John Wiley & Sons, Ltd.
Frequent expression of the multi‐drug resistance‐associated protein BCRP/MXR/ABCP/ABCG2 in human tumours detected by the BXP‐21 monoclonal antibody in paraffin‐embedded material
Authors: Diestra Julio E. , Scheffer George L. , Català Isabel , Maliepaard Marc , Schellens Jan H. M. , Scheper Rik J. , Germà‐Lluch Jose R. , Izquierdo Miguel A.
Published: October 2002

Breast cancer resistance protein (BCRP/MXR/ABCP/ABCG2; hereafter ABCG2) is a member of the ATP‐binding‐cassette family of transporters that causes multi‐drug resistance to various anticancer drugs. The expression of ABCG2 in human tumours and its potential involvement in clinical drug resistance are unknown. Recently, two monoclonal antibodies against human ABCG2 were produced, BXP‐34 and BXP‐21. This study describes an immunohistochemical method using BXP‐21 to study ABCG2 expression in formalin‐fixed, paraffin‐embedded tissues. No staining was seen using BXP‐34 with the same protocols. The expression of ABCG2 was then investigated in a panel of 150 untreated human solid tumours comprising 21 tumour types. Overall, ABCG2 expression was frequent. Specificity of immunohistochemistry was confirmed by the detection of a 72 kD band in western blotting. ABCG2 expression was seen in all tumour types, but it seemed more frequent in adenocarcinomas of the digestive tract, endometrium, and lung, and melanoma. Positive tumours showed membranous and cytoplasmic staining. In certain adenocarcinomas, prominent membranous staining was seen. Endothelial cells frequently displayed moderate to strong staining. ABCG2 is widely present in untreated human solid tumours and may represent a clinically relevant mechanism of drug resistance. Future studies in specific tumour types are needed to ascertain its clinical relevance. BXP‐21 and the immunohistochemical protocol described here will be of value in these investigations. Copyright © 2002 John Wiley & Sons, Ltd.
Presence of pharmacoepidemiology in three bibliographic databases: Medline, IPA and SCI
Authors: Arrebola‐Pascual I. , García‐López J. A.
Published: October 2002

Objective

The objective of this study is to make a comparative description of the evolution and distribution of international research into pharmacoepidemiology, using three bibliographic databases, in order to select the most appropriate for future bibliometric studies.

Methods

Bibliographic searches were performed using the following databases: Medline (1966–99), IPA (1970–99) and SCI (1990–99), using the term ‘pharmacoepidemiology’. On the basis of these searches, the number of original articles per year and per journal title were noted. The growth of the output of scientific writing was found to fit Price's law.

Results

A total of 845 original articles were recovered: 467 from IPA, 219 from Medline and 159 from SCI. The highest mean number of original articles per year (33.4) was obtained with the IPA database. Price's exponential growth pattern was observed among all three databases. The total numbers of journals in which the original articles were published were 102 in Medline, 65 in IPA and 60 in SCI. The journals providing a single original article comprised 65% of the Medline titles and 61% of those in IPA and SCI.

Conclusions

International research into pharmacoepidemiology presents an exponential growth pattern, in accordance with Price's law. There is a large degree of publishing dispersion. IPA was found to be the bibliographic database that recovered the greatest number of original articles, nearly half of which were published in Pharmacoepidemiology and Drug Safety. We therefore consider the latter database appropriate for bibliometric studies in the field of pharmacoepidemiology. Copyright © 2002 John Wiley & Sons, Ltd.
The relationship between cognitive emotion regulation strategies and emotional problems: comparison between a clinical and a non‐clinical sample
Authors: Garnefski Nadia , Van Den Kommer Tessa , Kraaij Vivian , Teerds Jan , Legerstee Jeroen , Onstein Evert
Published: October 2002

This study focuses on the relationship between the use of specific cognitive emotion regulation strategies and emotional problems. Two samples were included: 99 adults from a clinical population and 99 matched non‐clinical adults. Data was obtained in both groups on the use of nine cognitive emotion regulation strategies: self‐blame, other‐blame, rumination, catastrophizing, putting into perspective, positive refocusing, positive reappraisal, acceptance, and refocus on planning.

Logistic regression analyses show that self‐blame, catastrophizing, and positive reappraisal were, relative to the other strategies, the most important variables for distinguishing between the two samples. While the first two strategies were reported significantly more often by the clinical than by the non‐clinical sample, positive reappraisal was reported significantly more often by the non‐clinical sample. The results suggest that cognitive emotion regulation strategies may be a useful target for prevention and intervention. Copyright © 2002 John Wiley & Sons, Ltd.
Adiabatic connection method for X− + RX nucleophilic substitution reactions (X = F, Cl)
Authors: Kormos Bethany L. , Cramer Christopher J.
Published: October 2002

A modified Perdew–Wang one‐parameter hybrid density functional (mPW1N) was developed for nucleophilic substitution reactions by optimizing the fraction of exact exchange in vPW1PW91/6–31+G(d). Activation energies for 20 identity nucleophilic substitution and alkyl halide heterolysis reactions involving fluorine and chlorine were compared to values computed at the MCG3//MC‐QCISD level to arrive at an optimal value of 40.6% HF exchange in mPW1N. This choice also leads to improved transition‐state geometries over the training set. Results from mPW1N are compared with those from other common DFT methods, and some sources of error are explored. Copyright © 2002 John Wiley & Sons, Ltd.
Novel block ionomers. I. Synthesis and characterization of polyisobutylene‐based block anionomers
Authors: Fang Zheng , Kennedy Joseph P.
Published: October 2002

A series of novel block anionomers consisting of polyisobutylene (PIB) and poly(methacrylic acid) (PMAA) segments were prepared and characterized. The specific targets were various molecular weight diblocks (PIB‐b‐PMAA−), triblocks (PMAA−‐b‐PIB‐b‐PMAA−), and three‐arm star blocks [Φ(PIB‐b‐PMAA−)3] consisting of rubbery PIB blocks with a number‐average degree of polymerization of 50–1000 (number‐average molecular weight = 3000–54,000 g/mol) connected to blocks of PMAA− anions with a number‐average degree of polymerization of 5–20. The overall strategy for the synthesis of these constructs consisted of four steps: (1) synthesis by living cationic polymerization of t‐chloro‐monotelechelic, t‐chloro‐ditelechelic, and t‐chloro‐tritelechelic PIBs; (2) site transformation to obtain PIBs fitted with termini capable of mediating the atom transfer radical polymerization (ATRP) of tert‐butyl methacrylate (tBMA); (3) ATRP of tBMA, and (4) hydrolysis of poly(tert‐butyl methacrylate) to PMAA−. The architectures created and the synthesis steps employed are summarized. Kinetic and model experiments greatly assisted in the development of convenient synthesis methods. The microarchitectures of the various block anionomers were confirmed by spectroscopy and other techniques. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3662–3678, 2002
Low dielectric thermoset. II. Synthesis and properties of novel 2,6‐dimethyl phenol–dipentene epoxy
Authors: Lin Ching Hsuan , Jiang Zheng Rong , Wang Chun Shan
Published: October 2002

A 2,6‐dimethyl phenol–dipentene adduct was synthesized from dipentene (DP) and 2,6‐dimethyl phenol, and then a 2,6‐dimethyl phenol–DP epoxy was synthesized from the reaction of the resultant 2,6‐dimethyl phenol–DP adduct and epichlorohydrin. The proposed structures were confirmed by Fourier transform infrared, elemental analysis, mass spectra, NMR spectra, and epoxy equivalent weight titration. The synthesized 2,6‐dimethyl phenol–DP adduct was cured with 4,4‐diamino diphenyl methane, phenol novolac, 4,4‐diamino diphenyl sulfone, and 4,4‐diamino diphenyl ether. The thermal properties of the cured epoxy resins were studied with differential scanning calorimetry, dynamic mechanical analysis, dielectric analysis, and thermogravimetric analysis. These data were compared with those for the bisphenol A epoxy system. The cured 2,6‐dimethyl phenol–DP epoxy exhibited a lower dielectric constant (ca. 3.1), a lower dissipation factor (ca. 0.065), a lower modulus, lower thermal stability (5% degradation temperature = 366–424 °C), and lower moisture absorption (1.21–2.18%) than the bisphenol A system but a higher glass‐transition temperature (ca. 173–222 °C) than that of bisphenol A system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4084–4097, 2002
Multiple melting behavior of poly(butylene succinate). I. Thermal analysis of melt‐crystallized samples
Authors: Yasuniwa Munehisa , Satou Tadashi
Published: October 2002

The multiple melting behavior of poly(butylene succinate) (PBSu) was studied with differential scanning calorimetry (DSC). Three different PBSu resins, with molecular weights of 1.1 × 105, 1.8 × 105, and 2.5 × 105, were cooled from the melt (150 °C) at various cooling rates (CRs) ranging from 0.2 to 50 K min−1. The peak crystallization temperature (Tc) of the DSC curve in the cooling process decreased almost linearly with the logarithm of the CR. DSC melting curves for the melt‐crystallized samples were obtained at 10 K min−1. Double endothermic peaks, a high‐temperature peak H and a low‐temperature peak L, and an exothermic peak located between them appeared. Peak L decreased with increasing CR, whereas peak H increased. An endothermic shoulder peak appeared at the lower temperature of peak H. The CR dependence of the peak melting temperatures [Tm(L) and Tm(H)], recrystallization temperature (Tre), and heat of fusion (ΔH) was obtained. Their fitting curves were obtained as functions of log(CR). Tm(L), Tre, and ΔH decreased almost linearly with log(CR), whereas Tm(H) was almost constant. Peak H decreased with the molecular weight, whereas peak L increased. It was suggested that the rate of the recrystallization decreased with the molecular weight. Tm(L), Tm(H), Tre, and Tc for the lowest molecular weight sample were lower than those for the others. In contrast, ΔH for the highest molecular weight sample was lower than that for the others. If the molecular weight dependence of the melting temperature for PBSu is similar to that for polyethylene, the results for the molecular weight dependence of PBSu can be explained. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2411–2420, 2002
Oxygen‐barrier properties of cold‐crystallized and melt‐crystallized poly(ethylene terephthalate‐co‐4,4′‐bibenzoate)
Authors: Hu Y. S. , Liu R. Y. F. , Rogunova M. , Schiraldi D. A. , Nazarenko S. , Hiltner A. , Baer E.
Published: October 2002

This study examined the oxygen‐transport properties of poly(ethylene terephthalate‐co‐bibenzoate) (PETBB55) crystallized from the melt (melt crystallization) or quenched to glass and subsequently isothermally crystallized by heating above the glass‐transition temperature (cold crystallization). The gauche–trans conformation of the glycol linkage was determined by infrared analysis, and the crystalline morphology was examined by atomic force microscopy. Oxygen solubility decreased linearly with volume fraction crystallinity. For melt‐crystallized PETBB55, extrapolation to zero solubility corresponded to an impermeable crystal with 100% trans glycol conformations, a density of 1.396 g cm−3, and a heat of melting of 83 J g−1. From the melt, PETBB55 crystallized as space‐filling spherulites with loosely organized lamellae and pronounced secondary crystallization. The morphological observations provided a structural model for permeability consisting of impermeable platelets randomly dispersed in a permeable matrix. In contrast, cold‐crystallized PETBB55 retained the granular texture of the quenched polymer despite the high level of crystallinity, as measured by the density and heat of melting. Oxygen solubility decreased linearly with volume fraction crystallinity, but zero solubility corresponded to an impermeable defective crystal with a trans fraction of 0.83 and a density of 1.381 g cm−3. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2489–2503, 2002
Specificity and versatility of nucleating agents toward isotactic polypropylene crystal phases
Authors: Mathieu C. , Thierry A. , Wittmann J. C. , Lotz B.
Published: October 2002

Nucleating agents with an ≈6.5 Å lattice parameter induced the α phase of isotactic polypropylene (iPP, α‐iPP). A 6.5 Å periodicity is also involved in the nucleating agents for the β phase of iPP (β‐iPP). The similarity in substrate periodicities suggests that some nucleating agents may induce either the α or β phase under different crystallization conditions. 4‐Fluorobenzoic acid, dicyclohexylterephthalamide, and γ‐quinacridone (the latter two are known as β‐iPP nucleators) were tested over a wide range of crystallization temperatures [up to crystallization temperature (Tc) > 145 °C]. The two former nucleating agents induce exclusively α‐iPP and β‐iPP, respectively. γ‐Quinacridone on the contrary is a versatile agent with respect to the crystal phase generated. More specifically, the same crystal face of γ‐quinacridone induces either β‐iPP or α‐iPP when Tc is below or above ≈140 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2504–2515, 2002
Morphology and thermal properties of conductive polyaniline/polyamide composite films
Authors: Zhang Qinghua , Wang Xianhong , Geng Yanhou , Chen Dajun , Jing Xiabin
Published: October 2002

Polyaniline (PANI) in an emeraldine‐base form, synthesized by chemical oxidation polymerization, was doped with camphor sulfonic acid (CSA). The conducting complex (PANI–CSA) and a matrix, polyamide‐66, polyamide‐11, or polyamide‐1010, were dissolved in a mixed solvent, and the blend solution was dropped onto glass and dried for the preparation of PANI/polyamide composite films. The conductivity of the films ranged from 10−7 to 100 S/cm when the weight fraction of PANI–CSA in the matrices changed from 0.01 to 0.09, and the percolation threshold was about 2 wt %. The morphology of the composite films before and after etching was studied with scanning electron microscopy, and the thermal properties of the composite films were monitored with differential scanning calorimetry. The results indicated that the morphology of the blend systems was in a globular form. The addition of PANI–CSA to the films resulted in a decrease in the melting temperature of the composite films and also affected the crystallinity of the blend systems. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2531–2538, 2002