bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of Poly(ethylene glycol) Dimethacrylate Hydrogels
Authors: Lin‐Gibson Sheng , Bencherif Sidi , Antonucci Joseph M. , Jones Ronald L. , Horkay Ferenc
Published: August 2005

Facile synthesis and detailed characterization of photo‐polymerizable and biocompatible poly(ethylene glycol) dimethacrylates (PEGDM) and their hydrogels are described. Combined analyses of 1H NMR and MALDI‐TOF MS confirmed the formation of prepolymers of high purity and narrow mass distribution (PD < 1.02). A systematic investigation into the structure and mechanical properties of PEGDM hydrogels was performed to characterize the relationships between the network structure and gel properties. Small‐angle neutron scattering was used to characterize the structural features of hydrogels with respect to their semidilute solution precursors. A well‐defined structural length scale (correlation length) manifested as a maximum in the scattering intensity was observed for hydrogels derived from high molecular mass PEGDMs and/or high oligomer mass fractions. Hydrogels derived from lower molecular mass PEGDMs and/or low oligomer mass fractions exhibited multiple correlation lengths suggesting the formation of inhomogeneous gel structures. The shear moduli, determined from uniaxial compression measurement, showed that the gel structures correlate well with the gel mechanical properties.
New Nanophase Separated Intelligent Amphiphilic Conetworks and Gels
Authors: Iván Béla , Haraszti Márton , Erdődi Gábor , Scherble Jonas , Thomann Ralf , Mülhaupt Rolf
Published: August 2005

Amphiphilic conetworks (APCN) are new materials composed of covalently bonded otherwise immiscible hydrophilic and hydrophobic polymer chains. The amphiphilic nature of these new crosslinked polymers is indicated by their swelling ability in both hydrophilic and hydrophobic solvents. Special synthetic techniques have been developed for the preparation of these new unique materials, such as poly(2‐hydroxyethyl methacrylate)‐l‐polyisobutylene (PHEMA‐l‐PIB), poly(methacrylic acid)‐l‐polyisobutylene (PMAA‐l‐PIB) and poly(N,N‐dimethylaminoethyl methacrylate)‐l‐polyisobutylene (PDMAEMA‐l‐PIB) (‐l‐ stands for linked by). Due to their unique architecture, macrophase separation of the immiscible components is prevented by the chemical bonding in the conetworks. As a results, phase separation leads to nanodomains with usually 2‐20 nm domain sizes as shown by AFM measurements. The nanophase separated morphology may also lead to smart temperature responsive gels with high mechanical stability, such as in the case of poly(N,N‐dimethylaminoethyl methacrylate)‐l‐polyisobutylene APCNs as discovered during these studies. In another approach, poly(2‐hydroxyethyl methacrylate)‐l‐polyisobutylene and poly(methacrylic acid)‐l‐polyisobutylene APCNs were prepared by a special two‐step process. The new PMAA‐l‐PIB polyelectrolyte APCNs possess smart (intelligent) reversible pH‐responsive properties in aqueous media. These unique conetwork structures and properties of these new emerging materials may lead to numerous new potential applications, such as smart materialk products, sustained drug release matrices, biomaterials, nanohybrids, nanotemplates etc.
Ionic Diffusion in Polymers
Authors: Boeykens Susana P. , Daraio Marta E. , Temprano Norma , Rosen Marta
Published: August 2005

Scleroglucan aqueous solutions and gels were selected to study the dependence of diffusion behavior of alkali and alkaline‐earth metal ions on matrix structural characteristics. Stokes and free diffusion experimental methods for obtaining diffusion coefficients were contrasted. Three different behaviors, corresponding to three well‐defined concentration regimes of the polymeric system were found.
Ion‐Dependent Hydration and Transparency of the Corneal Stroma, a Polyelectrolyte Biogel
Authors: Huff Joseph William , Jimoh Olanrewaju , Uhakheme Maxwell , Sukhitashvili George
Published: August 2005

The cornea is the clear outer window of the eye, composed primarily of dense regular connective tissue called the stroma. The tissue is composed of 70% water and parallel collagen fibrils surrounded by proteoglycans containing high concentrations of acidic and neutral glycosaminoglycans (GAGs) and contains ∼2 – 10% cells by volume. When the surface membranes covering the stroma are damaged by injury or disease, the stroma swells due to the hydrophilic nature of the polysaccharides. At the same time, swelling spreads the collagen fibrils apart and the tissue loses transparency. We investigated the role of different salts in modifying swelling behavior and transparency loss. In saline (148 mM NaCl) solution, hydration increases as a multi exponential function of time: Initially the stroma gains hydration at a fast rate, then slows down. In the presence of divalent cations, swelling behavior significantly decreased, and the effect was weakly anion‐dependent. Under imposed stromal swelling pressures, Ca++ and Mg++ inhibited hydration equally, and their effects were additive, indicating that they work by similar mechanisms. They were also concentration‐dependent, with no apparent ceiling to the effect within normal biological ionic strengths. As stated above, Mg++ and Ca++ both dehydrate stromas and decrease swelling rates compared to saline, and as a stroma hydrates, it loses transparency: visible spectrophotometry of stromas bathed in NaCl lose transparency faster than those bathed in MgSO4, because MgSO4 solutions hydrate stromas slower. Stromas bathed in Ca++ hydrated slower than those bathed in NaCl, but interestingly, high (49 – 148 mM) concentrations of Ca++ caused transparency loss almost instantly. In hyaluronin (a collagen fibril‐free polyanionic biogel), when similar concentrations of Ca++ were added, transparency also decreased. Our conclusion is that the dehydrating effects of Mg++ and low concentrations of Ca++ are due to shielding of electrostatic repulsion between anionic GAGs. The higher concentrations of Ca++ dehydrate by a combination of covalent binding to (precipitating) GAGs and/or shielding their electrostatic repulsions, and scatter light by precipitating GAGs and disrupting collagen fibril order. These techniques and ionic probes are useful for studying the structure and function of polyionic hydrogels and may be useful for modifying the materials properties of biological and synthetic gels.
Laser Micropatterning of Polylactide Microspheres into Neuronal‐Glial Coculture for the Study of Axonal Regeneration
Authors: Bakken Daniel E. , Narasimhan Sriram V. , Burg Karen J.L. , Gao Bruce Z.
Published: August 2005

250,000 Americans suffer from spinal cord injury caused by vehicular, work, and sports related accidents[1]. After injury to the spinal cord, axons do not have the capability of regenerating across the lesioned site. To understand the mechanisms of axon regeneration and to identify a better method of regeneration, a new technique for mimicking and studying the in vivo cellular environment is needed. To meet this goal, we have developed a laser cell micropatterning system that uses a weakly focused laser beam to pattern both biological cells and nonbiological particles for the study of various cell‐cell‐polymer interactions. Using this system, we have successfully copatterned neurons, glial cells, and polymer microspheres into a viable matrix. These copatterns allow us to study the effects nerve growth factor has, when released from a degradable polymer microsphere, on a single neuron within a specific arrangement of multiple cell types.
A new concept for front‐end circuit integration: From single‐ended antenna to differential‐input connection without any external balun
Authors: Chen Hsien‐Ku , Juang Ying‐Zong , Chiu Chin‐Fong
Published: August 2005

A new concept for a single‐ended input front‐end circuit design is proposed. The coupling of a single‐ended low‐noise amplifier (LNA) to a double‐balanced cross‐coupled mixer using a single‐to‐differential transformer is successfully implemented and then tested in the 5.725–5.825‐GHz band in order to show its feasibility. Furthermore, this idea is even useful for wide‐receive‐band applications when the bandwidth of the LNA is designed widely. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 1–4, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21063
A novel genetic‐algorithm‐based artificial magnetic conductor structure
Authors: Qiang Gao , Yan Dun‐Bao , Fu Yun‐Qi , Yuan Nai‐Chang
Published: August 2005

In this paper, a novel genetic algorithm (GA)‐based AMC structure, which is made up of a high‐impedance frequency‐selective surface, is introduced. The aperture‐coupled microstrip antenna using this structure has 10‐dB less back radiation and 3–4‐dB more gain than a conventional one. This structure has important reference value for antenna manufacturing. A practical antenna is fabricated, and the measured results basically agree well with the simulated ones. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 20–22, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21069
Characterization and applications of a compact CPW defected ground structure
Authors: Karyamapudi Bindu M. , Hong J.‐S.
Published: August 2005

A compact coplanar waveguide (CPW) defected ground structure is investigated. Its frequency characteristics are modeled by full‐wave EM simulations. Some applications are investigated, including two electronic bandgap (EBG) devices which are constructed based on a periodical structure of the proposed defected ground without and with loading of lumped‐element capacitors. Also, a varactor‐tuned defected ground structure of this type has been demonstrated. The theoretical, simulated, and experimental results are presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 26–31, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21071
A concurrent multiband SiGe LNA for 1.8/1.9‐GHz GSM, 2.4/5.2/5.7‐GHz WLAN, and 5–7‐GHz ultrawideband (UWB) system applications
Authors: Lin Yo‐Sheng , Liao Kun‐Nan
Published: August 2005

A concurrent multiband low‐noise amplifier (LNA) for 1.8/1.9‐GHz GSM, 2.4/5.2/5.7‐GHz WLAN, and 5–7‐GHz ultra‐wideband (UWB) system applications is realized using 0.35‐μm SiGe BiCMOS technology. The LNA occupies an area of only 600 × 300 μm, excluding the test pads, because only two inductors are used. The first stage of the LNA provides high gain and input matching simultaneously at the 1.8/1.9‐GHz GSM and 2.4/5.2/5.7‐GHz WLAN bands. The output matching of the second stage is realized by shunt‐shunt feedback. It consumes only 14.4‐mW power and achieved transducer gains (S21) of 26.6, 26.3, 24.6, 15.8, and 14.8 dB, input return losses (S11) of‐8.4,‐9.9,‐22.4,‐12.3, and‐17.1 dB, noise figures of 1.81, 1.9, 2.41, 3.4, and 2.81 dB (for fully on‐chip input matching), and noise figures of 1.5, 1.6, 2.0, 2.82, and 2.32 dB (for off‐chip input matching) at 1.8, 1.9, 2.4, 5.2, and 5.7 GHz, respectively. In addition, very low and very flat NF versus frequency characteristics (below 3.0 dB) are achieved over a very wide frequency range (from 5 to 7.2 GHz), which means the implemented LNA is also very suitable for 5–7‐GHz UWB‐system applications. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 36–41, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21074
Image technique for multiresolution time‐domain using nonsymmetric basis functions
Authors: Kovvali Narayan , Lin Wenbin , Carin Lawrence
Published: August 2005

The image technique is required in order to model perfect‐electric‐conductor and perfect‐magnetic‐conductor boundary conditions using the multiresolution time‐domain (MRTD) method. The strategy of directly imposing the image principle on the field‐expansion coefficients is valid only if the basis functions of the multiresolution analysis are symmetric or satisfy the interpolation property. Here we address the rigorous incorporation of the image principle into the framework of the multiresolution time‐domain using nonsymmetric basis functions which do not satisfy the interpolation property. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 44–47, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21076
Compact slot‐coupled microstrip antennas with circular polarization
Authors: Chuo Feng‐Pin , Han Tuan‐Yung , Chen Tsair‐Rong
Published: August 2005

A compact circularly‐polarized (CP) design of a microstrip patch antennas is presented. The proposed antenna is fed by the coupling of a ring slot in the ground plane of a microstrip line. The results show that the required patch size of the proposed design at a fixed CP operating frequency has a reduction of 48%, as compared to a conventional CP microstrip antenna but, at the same time, its CP bandwidth is not decreased. Details of the simulated and experimental results are presented and discussed. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 57–59, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21080
A phase‐conjugating pair of coupled, dual‐gate, self‐oscillating mixers
Authors: Christodoulou Michael G. , Chrissoulidis Dimitrios P.
Published: August 2005

A novel phase conjugator for active retro‐directive operation is made by using twin, dual‐gate, self‐oscillating mixers mutually locked through a 12‐dB hybrid coupler. The coupling network incorporates the load of both oscillators. Reduced LO penetration is achieved at the IF port in two steps: (i) by trapping the LO signal within the dc bias lines of each self oscillating mixer and (ii) by the out‐of‐phase addition of any LO signal leakage. The input RF signal leaking through the mixers has also been suppressed by out‐of‐phase addition at the IF port. The measured results are presented for a phase conjugator designed for nominal operation at 900 MHz. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 59–62, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21081
Broadband 40‐GHz coherent source based on supercontinuum generation in highly nonlinear fiber
Authors: Xia Ge , Huang Dexiu , Chen Xiaogang , Yuan Xiuhua
Published: August 2005

A broadband 40‐GHz coherent source, which utilizes supercontinuum (SC) generated in highly nonlinear fiber (HNLF) with large normal dispersion is investigated for the first time. In order to enhance the SC generation in the HNLF, a new scheme that applies the chirp‐pulse compensation technique is presented and confirmed by the theoretical and experimental results. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 73–76, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21085
An EMC foam‐base chip antenna for WLAN operation
Authors: Wong Kin‐Lu , Chang Chih‐Hwa
Published: August 2005

A novel foam‐base chip antenna having an attractive property of electromagnetic compatibility (EMC) with the nearby conducting elements is presented. With the EMC property, the proposed antenna is very suitable to be applied in a mobile‐communication device as an internal antenna. For this kind of application, the antenna can be placed in very close proximity to the RF‐shielding metal case in the mobile device, without very small or negligible effects on the antenna performance, which can lead to a compact integration of the internal antenna with associated elements in the mobile device. A design example of the proposed antenna for wireless local‐area network (WLAN) operation in the 2.4‐GHz band is demonstrated. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 80–82, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21087
Circuit modeling of power/ground plane structures for printed circuit boards
Authors: Huang Chien‐Chang
Published: August 2005

With the increase of operating frequency and circuit‐component density, signal/power integrity issues due to ground bounces become more important for high‐speed digital systems. This paper presents a modal analysis resulting in a multiport equivalent circuit model for the power/ground plane structures in printed circuit boards including effects of dielectric, conductor, and radiation losses. Numerical results represented inZ‐parameters verified by the measured data are shown to validate the proposed approach. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 97–99, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21092
Crystallization and stereocomplexation governed self‐assembling of poly(lactide)‐b‐poly(ethylene glycol) to mesoscale structures
Authors: Slager Joram , Brizzolara Davide , Cantow Hans J. , Domb Abraham J.
Published: August 2005

The stereocomplex formation between enantioselective poly(lactide) (PLA) homopolymers is well understood. In this report an attempt is made to analyze the influence on the self‐assembling of the stereocomplex of enantiomorphic PLA‐PEG di‐ and tri‐blocks in different solvents. Powder diffraction studies showed the poly(ethylene glycol) (PEG) and the PLA blocks crystallize separately forming unique supra structures like rods, discs and coiled coils with dimensions in the micrometer scale in length and sub‐micrometer scale in diameter. The influence of the solvents on the crystal formation was shown in the formation of uniform structures. Discs emerged from equimolar mixtures of the D‐ and L‐configured di‐ and tri‐block copolymers, in dioxan and acetonitrile and in water the stereocomplexes crystallized mainly as rods. In some cases the rods were observed as coiled coils. The shape, the hydrophobic/hydrophilic content and the PEG coated surface of the discs give them a future potential as matrix for the controlled and targeted delivery of bioactive agents. Copyright © 2005 John Wiley & Sons, Ltd.
PAN composite membrane with different solvent affinities controlled by surface modification methods
Authors: Dragan Ecaterina Stela , Mihai Marcela , Schauer J. , Ghimici Luminita
Published: August 2005

Polyacrylonitrile (PAN) composite membranes with surface properties designed by either a chemical modification with ethylenediamine (EDA), or layer‐by‐layer (LbL) polyelectrolyte adsorption were investigated in this paper. Fourier‐transformed infrared (FTIR) spectroscopy and streaming potential measurements showed that the first step of the reaction with EDA in gas phase was the formation of ammonium salts with the reactive carboxylic groups present on the surface of the starting membrane. Part of the ammonium carboxylate groups was transformed in secondary amide linkages by a heat‐induced reaction. Poly(sodium styrenesulfonate) (NaPSS) and a polycation containing about 95 mol % of N,N‐dimethyl‐2‐hydroxypropyleneammonium chloride units in the backbone (PCA5) were used as opposite polyions in the LbL film construction. The adsorbed polyion amount per every layer was controlled by the nature and concentration of the supporting electrolyte in polyelectrolyte deposition solution (NaBr and KBr). An almost linear increase of the adsorbed polyion amount versus the layer pair number was observed. The swelling degree (SD) in pure alcohols of the LbL‐modified PAN composite membrane decreased with the increase of the solvent polarity and with the decrease of the pore volume by pore filling with polyelectrolyte complex multilayer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4161–4171, 2005
Synthesis and characterization of a new acceptor (n‐type) fluorinated and terminal‐functionalized polythiophene
Authors: Thomas Shanneth , Zhang Cheng , Sun Sam‐Shajing
Published: August 2005

Donor‐ or acceptor‐substituted polythiophenes have many potential applications in optoelectronics. Fluorinated polythiophenes are particularly attractive because of the presence of fluorine, which can withdraw electrons and also improve polymer chemical stability. Because of the promising future of these polymers, there has been much interest in identifying favorable synthetic routes to new fluorinated monomers and polymers. In this study, the monomer had an electron‐withdrawing fluorinated ester and was derived from 3‐thiophene carboxylic acid and 2,2,3,3,4,4,4‐heptafluoro‐1‐butanol. The synthesis of an n‐type fluorinated and terminal‐functionalized polythiophene was accomplished with the Ullmann coupling reaction. A polymer soluble in tetrahydrofuran was obtained with a molecular weight of approximately 15,000 g/mol. In solution, it exhibited a band gap of 2.4 eV, and the photoluminescent excitation and emission maxima were 370 nm and 555 nm, respectively. All peaks were bathochromically shifted when they were measured in the solid state. The glass‐transition and decomposition (in air) temperatures were 129 and 493 °C, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4280–4287, 2005
High‐molecular‐weight poly(1,5‐dioxepan‐2‐one) via enzyme‐catalyzed ring‐opening polymerization
Authors: Srivastava Rajiv K. , Albertsson Ann‐Christine
Published: August 2005

To avoid organometallic catalysts in the synthesis of poly(1,5‐dioxepan‐2‐one), the enzymatic ring‐opening polymerization of 1,5‐dioxepan‐2‐one (DXO) was performed with lipase CA (derived from Candida antarctica) as a biocatalyst. A linear relationship between the number‐average molecular weight and monomer conversion was observed, and this suggested that the product molecular weight could be controlled by the stoichiometry of the reactants. The monomer consumption followed a first‐order rate law with respect to the monomer, and no chain termination occurred. Water acted as a chain initiator, but it could cause polymer hydrolysis when it exceeded an optimum level. An initial activation via the heating of the enzyme was sufficient to start the polymerization, as the monomer conversion occurred when samples were left at room temperature after an initial heating at 60 °C. A high lipase content led to a high monomer conversion as well as a high molecular weight. An increase in the monomer conversion and molecular weight was observed when the polymerization temperature was increased from 40 to 80 °C. A further increase in the polymerization temperature led to a decrease in the monomer conversion and molecular weight because of the denaturation of the enzyme at elevated temperatures. The polymerization behavior of DXO under lipase CA catalysis was compared with that of ε‐caprolactone (CL). The rate of monomer conversion of DXO was much faster than that of CL, and this may have been due to differences in their specificity toward lipase CA. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4206–4216, 2005
Teenage asthma after severe early childhood wheezing: An 11‐year prospective follow‐up
Authors: Hyvärinen Mari K. , Kotaniemi‐Syrjänen Anne , Reijonen Tiina M. , Korhonen Kaj , Korppi Matti O.
Published: August 2005

The role of factors related to early wheezing and their associations with subsequent development of asthma are controversial. We reevaluated 81 children who had been prospectively followed up since hospitalization for wheezing at less than 2 years of age. The baseline data on characteristics of the children, family‐related factors, and viral causes of wheezing were collected on entry into the study. At the median age of 12.3 years, current symptoms suggestive of asthma and allergy were recorded. As part of the clinical examination, an outdoor exercise challenge test and skin prick tests to common inhalant allergens were performed. Asthma, as indicated by current inhaled anti‐inflammatory medication or repeated wheezing and positive result in the challenge test, was present in 32 (40%) children, and 90% of them were sensitized to at least one allergen. Early asthma‐predictive factors were atopic dermatitis (odds ratio (OR), 3.5; 95% confidence interval (CI), 1.2–10.1) and the presence of specific IgE to inhalant allergens (OR, 11.3; 95% CI, 1.9–67.6). Respiratory syncytial virus (RSV) identification during wheezing in infancy was relatively rare (20%) among later asthmatics compared with other or no viral identification (52%) or rhinovirus identification (58%). Since the prevalence of childhood asthma in our area is 4.0–5.0%, we conclude that the increased risk of asthma persists until the teenage years after hospitalization for wheezing in infancy. The risk was about 5‐fold after respiratory syncytial virus‐induced wheezing, and more than 10‐fold after rhinovirus‐induced wheezing in the present study. Pediatr Pulmonol. © 2005 Wiley‐Liss, Inc.
Pulmonary function and structure following mild preterm birth in lambs
Authors: Cock Megan , Hanna Mary , Sozo Foula , Wallace Megan , Yawno Tamara , Suzuki Keiji , Maritz Gert , Hooper Stuart , Harding Richard
Published: August 2005

Our objective was to determine whether postnatal respiratory function, lung growth, and lung structure are affected by preterm birth which did not require neonatal respiratory support. Two groups of preterm (P) lambs were delivered 2 weeks before term, at 133 days of gestational age (GA). Tissue was collected at term equivalent age (TEA, 147 days GA) in one P group and at 6 weeks post‐TEA in the other. Tissue was also collected from control (C) lambs soon after term birth (TEA) and at 6 weeks post‐TEA. Lung function was assessed at TEA and 6 weeks post‐TEA. Respiratory system compliance (Crs/kg BWT) was not different between P and C groups at TEA, but was higher (P = 0.02) in P lambs at 6 weeks post‐TEA. Pulmonary resistance was 62% higher in P lambs than controls (P = 0.07) at TEA, and remained higher at 6 weeks post‐TEA. Lung weights (wet and dry) were greater (P < 0.05) in preterm animals at both ages; when adjusted for body weight, only dry lung weight remained higher at 6 weeks post‐TEA. Alveoli were more numerous (P = 0.05) and smaller (P = 0.05) in preterm lambs compared to controls at both ages. Alveolar septa were 33% thicker and the blood‐air barrier was 26% thicker in P lambs than in controls at TEA, and remained thicker at 6 weeks post‐TEA. In P lambs, the airway epithelium was thicker at TEA and 6 weeks post‐TEA. At TEA, pulmonary tropoelastin expression was 27% lower in P lambs. At 6 weeks post‐TEA, dry lung weight and lung protein content were ∼50% greater in preterm lambs than in controls (P < 0.05), whereas lung DNA, elastin, and collagen contents were similar in the two groups. We conclude that mild preterm birth per se leads to both transient and persistent changes in lung development. Persistent increases in lung protein content and in the thickness of the airway epithelium, and a greater number of smaller alveolar, may alter later lung function. Pediatr Pulmonol. © 2005 Wiley‐Liss, Inc.
Investigations of atomic structure and bonding at domain boundaries in bulk La0.5Eu0.2Sr0.3MnO3
Authors: Sun B. Z. , He L. L. , Luo F. , Yan C. H.
Published: August 2005

The article [1] featured on the cover of this issue investigates the formation of the orthorhombic phase and 120° large‐angle orientation domains in bulk La0.7Sr0.3MnO3 compound doped with Eu. The cover picture is a transmission electron microscopy image of the domain boundaries of this phase. Insets show the composite [012] zone electron diffraction pattern (bottom right) and diffraction patterns from the single domains. The 120° rotational symmetry originates from the three‐fold axis of the high‐temperature pseudo‐cubic phase.

The first author is a Ph. D. candidate in the Institute of Metal Research of the Chinese Academy of Sciences, working on microstructural characterization on the atomic scale for colossal magnetoresistance materials.

This issue does also contain an important Rapid Research Letter contribution by Cai and Sandhage [2] on the shape‐preserving reactive conversion of biosilica shell surfaces of diatoms, a topic at the interface of materials and biological sciences.
Alternative formulation of the matrix elements in MP2‐R12 theory
Authors: Kedžuch Stanislav , Milko Matúš , Noga Jozef
Published: August 2005

A formulation of MP2‐R12 theory is presented leading to simplified matrix elements in the R12 part. The resulting formulas are free from the integrals over the commutator of the kinetic operator with inter‐electronic distance, which means a substantial decreasing of the computational demands. The use of an auxiliary basis set for the resolution of identity is discussed. First results using the standard approximation are compared with the former variants of MP2‐R12 for CH2, CH4, NH3, H2O, HF, CO, CH3OH, N2, and F2. The results show that the new formulation is not only less demanding, but also preferred concerning the convergence properties toward the basis set limit. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Symbolic NMR product operator calculations
Authors: Güntert Peter
Published: August 2005

Symbolic nuclear magnetic resonance (NMR) product operator calculations provide an analytic, intuitive, yet precise description of the time evolution of the density operator during an NMR experiment. NMR experiments are implemented as pulse sequences consisting of short radiofrequency pulses separated by delay periods during which the spin system evolves under the influence of the static external magnetic field and spin–spin interactions. The quantum mechanical calculations to follow the time evolution of the density operator can be decomposed into the repeated application of a set of simple rules, known as the product operator formalism, that naturally lend themselves to symbolic computation. This article describes a complete implementation of the NMR Product Operator formalism in MAthematica (POMA), which has greatly simplified the development of many NMR pulse sequences, and provided insight into their functioning. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Stand development and regeneration during a 33‐year period in a seral Picea glehnii forest, northern Japan
Authors: Takahashi Koichi , Yogo Masaru , Ishibashi Satoshi
Published: August 2005

Stand development and regeneration were studied during a 33‐year period (1965‐1998) in a 1‐ha plot in a seral Picea glehnii forest in northern Japan. P. glehnii was mono‐dominant in the upper canopy layer, but its understory trees were rarely found in 1965. Other species were scarcely observed in 1965. Many recruited saplings of Abies sachalinensis which had grown to > 5 cm diameter at breast height (DBH) by 1998 had become dominant in the understory layer. Mortality of P. glehnii canopy trees was low. Therefore, the stand basal area increased during the census period due to the growth of surviving canopy trees. Stand development brought about intense competition among trees by increasing local crowding for each tree, and promoted dominance of larger trees and suppression of smaller trees. Although growth rates of understory trees of the two conifers decreased with the increase in local crowding, the growth rate of A. sachalinensis was consistently higher than that of P. glehnii at all extents of local crowding. The recruitment rate (growing to ≥ 5 cm DBH) of the two conifers was less affected by local crowding. However, the number of recruits of P. glehnii was only about a quarter of that of A. sachalinensis during the census period because the regeneration of P. glehnii was largely restricted to fallen logs and within 1 m of the base of any live tree > 20 cm DBH. Therefore, our long‐term study suggests that A. sachalinensis will dominate over P. glehnii in the seral forest because of higher recruitment and growth rates of the former than the latter in the understory.
An ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes
Authors: Healy Sarah N. , McCulloch Andrew D.
Published: August 2005

Aims

To develop an ionic model of stretch-activated and stretch-modulated currents in rabbit ventricular myocytes consistent with experimental observations, that can be used to investigate the role of these currents in intact myocardium.

Methods and results

A non-specific cation-selective stretch-activated current Ins, was incorporated into the Puglisi–Bers ionic model of epicardial, endocardial and midmyocardial ventricular myocytes. Using the model, we predict a reduction in action potential duration at 20% repolarization (APD20) and action potential amplitude, an elevated resting transmembrane potential and either an increase or decrease in APD90, depending on the reversal potential of Ins. A stretch-induced decrease in IK1 (70%), plus a small Ins current (gns=10 pS), results in a reduction in APD20 and increase in APD90, and a reduced safety factor for conduction. Increasing IK1 (150%) plus a large Ins current (gns=40 pS), also leads to a reduction in APD20 and increase in APD90, but with a greater safety factor. Endocardial and midmyocardial cells appear to be the most sensitive to stretch-induced changes in action potential. The addition of the K+-specific stretch-activated current (SAC) IKo results in action potential shortening.

Conclusion

Transmural heterogeneity of IKo may reduce repolarization gradients in intact myocardium caused by intrinsic ion channel densities, nonuniform strains and electrotonic effects.
Functional essentiality from topology features in metabolic networks: A case study in yeast
Authors: Palumbo Maria Concetta , Colosimo Alfredo , Giuliani Alessandro , Farina Lorenzo
Published: August 2005

The relation between the position of mutations in Saccharomyces cerevisiae metabolic network and their lethality is the subject of this work. We represent the topology of the network by a directed graph: nodes are metabolites and arcs represent the reactions; a mutation corresponds to the removal of all the arcs referring to the deleted enzyme. Using publicly available knock‐out data, we show that lethality corresponds to the lack of alternative paths in the perturbed network linking the nodes affected by the enzyme deletion. Such feature is at the basis of the recently recognized importance of ‘marginal’ arcs of metabolic networks.
Mutational analysis of the active center of plant fructosyltransferases: Festuca 1‐SST and barley 6‐SFT
Authors: Altenbach Denise , Nüesch Eveline , Ritsema Tita , Boller Thomas , Wiemken Andres
Published: August 2005

The active center of the glycoside hydrolase family 32 contains the three characteristic motifs (N/S)DPNG, RDP, and EC. We replaced the N‐terminal region including the (N/S)DPNG motif of barley 6‐SFT (sucrose:fructan 6‐fructosyltransferase) by the corresponding region of Festuca 1‐SST (sucrose:sucrose 1‐fructosyltransferase). The chimeric enzyme, expressed in Pichia, retained the specificity of 6‐SFT. Attempts to replace a larger piece at the N‐terminus including also the RDP motif failed. A point mutation introduced in the RDP motif of 1‐SST abolished enzymatic activity. Interestingly, point mutations of the EC‐motif resulted in an enzyme which had lost the capability to form 1‐kestose and glucose from sucrose but still accepted 1‐kestose, producing fructose and sucrose as well as nystose.
Characterization of a poplar NIMA‐related kinase PNek1 and its potential role in meristematic activity
Authors: Cloutier Monikca , Vigneault Frédéric , Lachance Denis , Séguin Armand
Published: August 2005

Meristems are sites of undifferentiated cell division, which carry on developing into functional organs. Using the two‐hybrid system with a poplar 14‐3‐3, we uncovered poplar NIMA‐related kinase 1 (PNek1) as an interacting protein. PNek1 shows high homology to the mammalian NIMA‐related kinases, which are thought to be involved in cell cycle progression. Using a synchronized poplar cell suspension, we observed an accumulation of PNek1 mRNA at the G1/S transition and throughout the G2‐to‐M progression. Moreover, PNek1‐GFP fusion protein localized in the cytoplasm and in both the nuclear and nucleolar regions. Overexpression of PNek1‐GFP in Arabidopsis caused morphological abnormalities in flower and siliques. Overall, these results suggest that PNek1 is involved in plant development.
Impairment of the activity of the xenobiotic‐metabolizing enzymes arylamine N‐acetyltransferases 1 and 2 (NAT1/NAT2) by peroxynitrite in mouse skeletal muscle cells
Authors: Dairou Julien , Dupret Jean-Marie , Rodrigues-Lima Fernando
Published: August 2005

Reactive nitrogen species and their by‐products, such as peroxynitrite, modulate many physiological functions of skeletal muscle. Peroxynitrite generation occuring under specific conditions, such as inflammation, may also lead to skeletal muscle dysfunction and pathologies. Arylamine N‐acetyltransferases (NATs) are xenobiotic‐metabolizing enzymes (XMEs) involved in the detoxification and/or metabolic activation of several drugs and chemicals. In addition to other XMEs, such as gluthatione S‐transferases or cytochromes P450, NAT enzymes are expressed in skeletal muscle. We show here that functional NAT1 and NAT2 isoforms are expressed in mouse myotubes and that peroxynitrite may impair their activity in these cells. We show that this inactivation is likely due to the irreversible modification of NATs catalytic cysteine residue in vivo. Our results suggest that peroxynitrite‐dependent inactivation of muscle XMEs such as NATs may contribute to muscle dysfunction by impairing the biotransformation activity of this key cellular defense enzyme system.
Doppler ultrasound assessment and serum cancer antigen 125 in the diagnosis of ovarian tumors
Authors: Erdoğan N. , Özçelik B. , Serin İ.S. , Akgün M. , Öztürk F.
Published: August 2005

Objective: To differentiate benign from malignant ovarian tumors based on sonographic detection of a solid component. Method: Sixty‐three women with ovarian masses were evaluated preoperatively by grayscale and power/color Doppler ultrasonographic examination, with specific predefined criteria for the solid component. Sensitivity, specificity, and positive and negative predictive values were calculated and assessed against the histopathologic outcome. The contribution of cancer antigen (CA) 125 levels to the diagnostic accuracy was also assessed. Result: Sensitivity, specificity, and positive and negative predictive values were 100%, 95.2%, 91.3% and 100%, respectively, with two false‐positive results. Had an elevated CA 125 level (> 35 U/mL) been included in the malignancy criteria, the false‐positive results would have been eliminated, giving an accuracy of 100%. Conclusion: Sonographic evaluation with predefined specific criteria for the detection of a solid tumor component is an accurate method of preoperative discrimination between benign and malignant ovarian tumors. A serum CA 125 assay may assist in eliminating false‐positive results.
Infected Palmar Pits: A Rare Presentation of Gorlin’s Syndrome
Authors: NASSAB R. , RAYATT S. , PEART F.
Published: August 2005

This paper presents a rare hand presentation of Gorlin’s Syndrome, also known as Naevoid Basal Cell Carcinoma Syndrome, which has not been reported previously. This condition is an autosomal dominant, multisystem condition whose diagnosis is important to ensure further surveillance and treatment of features of the condition not routinely dealt with by hand surgeons. However, hand surgeons should be aware of this condition and those parts of the syndrome which may present to them.
Cortical Motor Activation Patterns Following Hand Transplantation and Replantation
Authors: BRENNEIS C. , LÖSCHER W. N. , EGGER K. E. , BENKE T. , SCHOCKE M. , GABL M. F. , WECHSELBERGER G. , FELBER S. , PECHLANER S. , MARGREITER R. , PIZA-KATZER H. , POEWE W.
Published: August 2005

We studied cortical activation patterns by functional MRI in a patient who received bilateral hand transplantation after amputation 6 years ago and in a patient who had received unilateral hand replantation within 2 hours after amputation. In the early postoperative period, the patient who had had the hand transplantation revealed strong activation of a higher motor area, only weak activation of the primary sensorimotor motor cortex and no activation of the primary somatosensory cortex. At 1-year follow-up, a small increase in primary sensorimotor motor cortex activation was observed. Activation of the primary somatosensory cortex was only seen at the 2 year follow-up. By contrast, after hand replantation, the activation pattern was similar to that of the uninjured hand within 6 weeks. This included activation of the primary sensorimotor motor cortex, higher motor areas and primary somatosensory cortex. Transplantation after long-standing amputation results in cortical reorganization occurring over a 2-year period. In contrast, hand replantation within a few hours preserves a normal activation pattern.
Middle to Late Holocene glacial variations, periglacial processes and alluvial sedimentation on the higher Apennine massifs (Italy)
Authors: Giraudi Carlo
Published: August 2005

The major climatic variations that have affected the summit slopes of the higher Apennine massifs in the last 6000 yr are shown in alternating layers of organic matter-rich soils and alluvial, glacial and periglacial sediments. The burial of the soils, triggered by environmental–climatic variations, took place in several phases. For the last 3000 yr chronological correlations can be drawn between phases of glacial advance, scree and alluvial sedimentation and development of periglacial features. During some periods, the slopes were covered by vegetation up to 2700 m and beyond, while in other phases the same slopes were subject to glacial advances and periglacial processes, and alluvial sediments were deposited on the high plateaus. Around 5740–5590, 1560–1370 and 1300–970 cal yr B.P., organic matter-rich soils formed on slopes currently subject to periglacial and glacial processes; the mean annual temperature must therefore have been higher than at present. Furthermore, on the basis of the variations in the elevation of the lower limit reached by gelifraction, it can be concluded that the oscillations in the minimum winter temperatures could have ranged between 3.0°C lower (ca. 790–150 cal yr B.P.) and 1.2°C higher (ca. 5740–5590 cal yr B.P.) than present minimum winter temperatures. During the last 3000 yr the cold phases recorded by the Calderone Glacier advance in the Apennines essentially match basically the phases of glacial advance in the Alps.
The Integrity Gap: Canada's Environmental Policy and
Institutions
Authors: Rayner Jeremy
Published: August 2005

The Integrity Gap: Canada's Environmental Policy and
Institutions, Eugene Lee and Anthony Perl, eds., Vancouver: UBC Press,
2003, pp. xi, 288.

This collection, which grew out of papers presented at a conference at
the Sookyung Centre for Canadian Studies in Seoul in 1999, is one of a
number of recent publications to call attention to a peculiar feature of
Canadian environmental policy. In spite of our much publicized commitment
to greenery at home and our hectoring criticism of other countries'
environmental policies abroad, our own record, when closely examined,
proves to be lamentable and is actually getting worse in comparison with
our counterparts in the Organization for Economic Cooperation and
Development (OECD). This yawning gulf between promise and performance is
the “integrity gap” of Lee and Perl's title.
L'administration publique. De L'École classique au
nouveau management public
Authors: Burlone Nathalie
Published: August 2005

L'administration publique. De L'École classique au
nouveau management public, Jean Mercier, Québec, Les Presses de
l'Université Laval, 2002, 518 p.

Le livre de Jean Mercier, destiné à un public
d'étudiants, est un manuel d'introduction assez exhaustif
qui permet de s'initier à l'administration publique et
d'en apprendre les principaux processus, structures et
théories. L'auteur situe son ouvrage dans une perspective
temporelle et offre ainsi au lecteur un large éventail de
thèmes, de tendances et de théories qui touchent
l'administration publique. Ses exemples, souvent tirés du
secteur de l'environnement, reflètent les expériences
québécoise, canadienne et internationale.
Real Libertarianism Assessed: Political Theory after Van
Parijs
Authors: Dobuzinskis Laurent
Published: August 2005

Real Libertarianism Assessed: Political Theory after Van Parijs,
Andrew Reeve and Andrew Williams, eds., London: Palgrave, 2003, pp. x,
223

Philippe Van Parijs' Real Freedom for All (Oxford:
Clarendon Press, 1995) is one of the most stimulating contributions to
left-libertarianism published in the last decade. It is, therefore, not
surprising that an edited volume that critically examines his ideas has
now been published. The contributing authors (two of whom, Peter
Vallentyne and Hillel Steiner, are other well known left-libertarians)
raise interesting and often pointed questions, but they all have some good
things to say about Van Parijs' original proposal.
Kant and Liberal Internationalism
Authors: Munn Jamie
Published: August 2005

Kant and Liberal Internationalism, Antonio Franceschet, Basingstoke:
Palgrave Macmillan, 2002, pp. 164

Few political notions are at once so normative and so equivocal as
liberal internationalism. Today, the official discourse of the West
resounds with appeals to a term that was long a trademark of the Left.
Whatever sense is given it, the meaning of internationalism logically
depends on some prior conception of nationalism, since it only has
currency as a backward construction referring to its opposite. Yet while
nationalism is of all modern political phenomena the most
value-contested—judgements of its record standardly varying across a
180-degree span, from admiration to abhorrence—no such schizophrenia
of connotation affects internationalism: its implication is virtually
always positive. But the price of approval is indeterminacy. If no one
doubts the fact of nationalism, but few agree as to its worth, at the
entry to the millennium the status of internationalism would appear to be
more or less the reverse. It is claimed on all sides as a value, but who
can identify it without challenge in the form of force?
Du retour. Abécédaire biopolitique. Entretiens avec
Anne Dufourmantelle
Authors: Giroux Dalie
Published: August 2005

Du retour. Abécédaire biopolitique. Entretiens avec Anne
Dufourmantelle, Antonio Negri, Paris : Calmann-Lévy, 2002, 243
pages

Du retour est un entretien avec Antonio Negri mené par
la psychanalyste Anne Dufourmantelle. Negri est sorti des prisons
italiennes en 2003, après avoir été accusé
d'avoir participé, avec les Brigades rouges, à
l'assassinat d'Aldo Moro. Il est l'auteur, avec le
philosophe américain Michael Hardt, de Empire—un
ouvrage dont il n'est pas exagéré de dire qu'il
est désormais la référence théorique
principale du mouvement altermondialiste. L'intellectuel et
professeur italien, le “ mauvais maître ” , comme on
l'a appelé, a livré cet entretien en 2002 alors
qu'il était encore en semi-liberté.