bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of new injectable bulking agents: Biocompatibility of radiopaque polymeric microspheres studied in a mouse model
Authors: Emans Pieter J. , Saralidze Ketie , Knetsch Menno L. W. , Gijbels Marion J. J. , Kuijer Roel , Koole Leo H.
Published: May 2005

Radiopaque polymeric microspheres have a potential as new bulking agents for treatment of stress urinary incontinence (SUI). The advantage over existing bulking agents lies in their X‐ray visibility in situ; other polymeric bulking agents (e.g., PTFE or silicone rubbers) are practically radiolucent (i.e., incapable of absorbing X‐radiation). Radiopacity is useful in practice because of the high spatial accuracy of X‐ray imaging. For instance, X‐ray fluoroscopy can be used to assess possible migration of the bulking agent over time or to provide guidance in cases in which a second injection of a bulking agent is necessary (repeated treatment of SUI). Biocompatibility of injected radiopaque microspheres was investigated in vivo by using the mouse as a model. Microspheres were injected subcutaneously (9 animals) or intramuscularly (9 animals), and follow‐up was 8 days or 3 months. X‐ray fluoroscopy gave clear images of the miscrospheres as an ensemble, and it was found that no migration occurred during 3 months. Histopathology confirmed that all microspheres stayed close to the site of the injection. The microspheres appeared to be well tolerated; only a few giant cells, manifesting a mild inflammatory reaction, were encountered. At 3 months, cappillary blood vessels were observed throughout the microsphere beds, and macrophages and fibroblast cells were seen in between the microspheres. This is encouraging with respect to the intended application, although it must be acknowledged that the data refer merely to a mouse model. Further experiments with larger, more representative models (rabbit and goat) are in progress. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Novel functional biodegradable polymer. III. The construction of poly(γ‐glutamic acid)‐sulfonate hydrogel with fibroblast growth factor‐2 activity
Authors: Matsusaki Michiya , Serizawa Takeshi , Kishida Akio , Akashi Mitsuru
Published: May 2005

Poly(γ‐glutamic acid)‐sulfonate (γ‐PGA‐S) hydrogel, with fibroblast growth factor (FGF)‐2 activity was investigated as a novel, next‐generation tissue‐engineering material. γ‐PGA‐net‐γ‐PGA‐S72 (S72‐netgel) was prepared with γ‐PGA‐S and γ‐PGA‐S72 (72% sulfonated γ‐PGA) to provide the high mobility of γ‐PGA‐S72 for FGF‐2 activity. Cell adhesion and proliferation activities were evaluated on γ‐PGA and γ‐PGA‐S hydrogels along with S72‐netgels. Both cell adhesion and proliferation activities of γ‐PGA and γ‐PGA‐S hydrogels were low. In contrast, S72‐netgels had high cell adhesion and proliferation activities, because of their low swelling ratios and high sulfonic acid group concentrations. Furthermore, S72‐netgels had high FGF‐2 activity, because γ‐PGA‐S72 retained FGF‐2 activity when incorporated into S72‐netgels. S72‐netgels should be useful as next‐generation tissue‐engineering material containing FGF‐2 activity. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Evaluation of modifying collagen matrix with RGD peptide through periodate oxidation
Authors: Zhang Lihai , Hum Min , Wang Meng , Li Yanfeng , Chen Hua , Chu Chengbin , Jiang Hua
Published: May 2005

The aim of the study is to evaluate the effect of modifying collagen matrices with Arg‐Gly‐Asp (RGD) peptide through periodate oxidation. The collagen matrices were modified with RGD peptide, by periodate activation. The modified collagen matrices and unmodified matrices were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and electron spectroscopy for chemical analysis (ESCA). Mesenchymal stem cells (MSCs) were used to evaluate the cell compatibility of collagen matrices. In terms of cell growth, the MSCs attached much better on the modified matrix than on the unmodified one. But there was no significant difference between two groups regarding the MSC proliferation. Compared to the unmodified matrices, the mechanical strength of the modified matrix decreased sharply, and its 3D structure was destroyed. Introducing specific RGD receptor‐mediated adhesion sites on matrices obviously enhanced the MSC adhesion on collagen matrices, but the coupled method of periodate oxidation would likely result in the declination of the mechanical strength of the matrix, as well as the destruction of the matrix structure. This would affect the cell growth on the matrix, and decrease the histocompatibility of the matrices. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Effect of synovial fluid, phosphate‐buffered saline solution, and water on the dissolution and corrosion properties of CoCrMo alloys as used in orthopedic implants
Authors: Lewis A. C. , Kilburn M. R. , Papageorgiou I. , Allen G. C. , Case C. P.
Published: May 2005

The corrosion and dissolution of high‐ and low‐carbon CoCrMo alloys, as used in orthopedic joint replacements, were studied by immersing samples in phosphate‐buffered saline (PBS), water, and synovial fluid at 37°C for up to 35 days. Bulk properties were analyzed with a fine ion beam microscope. Surface analyses by X‐ray photoelectron spectroscopy and Auger electron spectroscopy showed surprisingly that synovial fluid produced a thin oxide/hydroxide layer. Release of ions into solution from the alloy also followed an unexpected pattern where synovial fluid, of all the samples, had the highest Cr concentration but the lowest Co concentration. The presence of carbide inclusions in the alloy did not affect the corrosion or the dissolution mechanisms, although the carbides were a significant feature on the metal surface. Only one mechanism was recognized as controlling the thickness of the oxide/hydroxide interface. The analysis of the dissolved metal showed two mechanisms at work: (1) a protein film caused ligand‐induced dissolution, increasing the Cr concentration in synovial fluid, and was explained by the equilibrium constants; (2) corrosion at the interface increased the Co in PBS. The effect of prepassivating the samples (ASTM F‐86‐01) did not always have the desired effect of reducing dissolution. The release of Cr into PBS increased after prepassivation. The metal–synovial fluid interface did not contain calcium phosphate as a deposit, typically found where samples are exposed to calcium rich bodily fluids. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
A combined freeze‐and‐cut strategy for the description of large molecular systems using a localized orbitals approach
Authors: Borini Stefano , Maynau Daniel , Evangelisti Stefano
Published: May 2005

A technique to reduce the computational effort in calculating ab initio energies using a localized orbitals approach is presented. By exploiting freeze strategy at the self‐consistent field (SCF) level and a cut of the unneeded atomic orbitals, it is possible to perform a localized complete active space (CAS‐SCF) calculation on a reduced system. This will open the possibility to perform ab initio treatments on very large molecular systems, provided that the chemically important phenomena happen in a localized zone of the molecule. Two test cases are discussed, to illustrate the performance of the method: the cis–trans interconversion curves for the (7Z)‐13 ammoniotridec‐7‐enoate, which demonstrates the ability of the method to reproduce the interactions between charged groups; and the cisoid–transoid energy barrier for the aldehydic group in the C13 polyenal molecule. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1042–1051, 2005
Practical conversion from torsion space to Cartesian space for in silico protein synthesis
Authors: Parsons Jerod , Holmes J. Bradley , Rojas J. Maurice , Tsai Jerry , Strauss Charlie E. M.
Published: May 2005

Many applications require a method for translating a large list of bond angles and bond lengths to precise atomic Cartesian coordinates. This simple but computationally consuming task occurs ubiquitously in modeling proteins, DNA, and other polymers as well as in many other fields such as robotics. To find an optimal method, algorithms can be compared by a number of operations, speed, intrinsic numerical stability, and parallelization. We discuss five established methods for growing a protein backbone by serial chain extension from bond angles and bond lengths. We introduce the Natural Extension Reference Frame (NeRF) method developed for Rosetta's chain extension subroutine, as well as an improved implementation. In comparison to traditional two‐step rotations, vector algebra, or Quaternion product algorithms, the NeRF algorithm is superior for this application: it requires 47% fewer floating point operations, demonstrates the best intrinsic numerical stability, and offers prospects for parallel processor acceleration. The NeRF formalism factors the mathematical operations of chain extension into two independent terms with orthogonal subsets of the dependent variables; the apparent irreducibility of these factors hint that the minimal operation set may have been identified. Benchmarks are made on Intel Pentium and Motorola PowerPC CPUs. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1063–1068, 2005
A CSOV study of the difference between HF and DFT intermolecular interaction energy values: The importance of the charge transfer contribution
Authors: Piquemal Jean‐Philip , Marquez Antonio , Parisel Olivier , Giessner–Prettre Claude
Published: May 2005

Intermolecular interaction energy decompositions using the Constrained Space Orbital Variation (CSOV) method are carried out at the Hartree–Fock level on the one hand and using DFT with usual GGA functionals on the other for a number of model complexes to analyze the role of electron correlation in the intermolecular stabilization energy. In addition to the overall stabilization, the results provide information on the variation, with respect to the computational level, of the different contributions to the interaction energy. The complexes studied are the water linear dimer, the N‐methylformamide dimer, the nucleic acid base pairs, the benzene–methane and benzene‐N2 van der Waals complexes, [Cu+‐(ImH)3]2, where “ImH” stands for the Imidazole ligand, and ImH‐Zn++. The variation of the frozen core energy (the sum of the intermolecular electrostatic energy and the Pauli repulsion energy) calculated from the unperturbed orbitals of the interacting entities indicates that the intramolecular correlation contributions can be stabilizing as well as destabilizing, and that general trends can be derived from the results obtained using usual density functionals. The most important difference between the values obtained from HF and DFT computations concerns the charge transfer contribution, which, in most cases, undergoes the largest increase. The physical meaning of these results is discussed. The present work gives reference calculations that might be used to parametrize new correlated molecular mechanics potentials. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1052–1062, 2005
Interleukin‐4 gene, but not the interleukin‐1 beta gene polymorphism, is associated with oral cancer
Authors: Tsai Ming‐Hsui , Chen Wen‐Chi , Tsai Chang‐Hai , Hang Liang‐Wen , Tsai Fuu‐Jen
Published: May 2005

We aimed to evaluate whether polymorphisms of the interleukin‐4 (IL‐4) gene promoter and intron 3 regions, and polymorphisms of the IL‐1 beta gene promoter and exon 5 regions are associated with oral cancer. This study included 130 patients with oral cancer and 105 age‐matched healthy controls who lived in the same area as the patients. Each genetic polymorphism was typed by polymerase chain reaction (PCR)‐based restriction analysis. We then compared the genotype distribution and allelic frequencies of each polymorphism between the oral cancer patients and the controls. The CC homozygote genotype of the IL‐4 gene promoter −590 region differed significantly between the patients with oral cancer and the controls (odds ratio (OR)=6.0, 95% confidence interval (CI)=1.2−30.7, chi‐square test, P=0.044). No significant difference in either the genotype distribution or the allelic frequencies of the IL‐1 beta gene polymorphisms was observed between patients with oral cancer and controls. The IL‐4 gene −590 C/T polymorphism is associated with oral cancer and is a suitable genetic marker for screening for oral cancer. However, whether the −590 C/T polymorphism of the IL4 gene plays a role in oral cancer remains unclear. Further substantiation based on larger patient samples is needed. J. Clin. Lab. Anal. 19:93–98, 2005. © 2005 Wiley‐Liss, Inc.
Image analysis systems for the detection of disseminated breast cancer cells on bone‐marrow cytospins
Authors: Becker Sven , Becker‐Pergola Graziella , Fehm Tanja , Emig Robert , Wallwiener Diethelm , Solomayer Erich‐Franz
Published: May 2005

We assessed the accuracy of automated cell imaging systems when compared to manual evaluation of cytospin slides in determining the presence of cytokeratin‐positive, disseminated breast cancer cells in bone marrow aspirates. A total of 298 cytospin slides of bone marrow aspirates were first evaluated by individual screening by one expert immunocytologist. Subsequently, all 298 slides were evaluated by the Automated Cell Imaging System (ACIS) by ChromaVision™. Two separate analysis cycles were performed using ACIS. The results of the two ACIS analysis cycles were almost identical: in 293 out of 298 samples (98.3%), identical numbers of disseminated breast cancer cells were detected. In the remaining five samples (1.7%), the result of the two ACIS analysis cycles differed by only one tumor cell. By using the manual technique, 120 cytospin samples were found to be positive. ACIS was able to detect additional tumor cells in 64 cases. Not once did ACIS miss tumor cells when compared to the manual technique. Using ACIS, we were able to determine the bone marrow status of patients with nonmetastatic breast cancer faster, with greater accuracy, and with greater reproducibility than with the manual technique. J. Clin. Lab. Anal. 19:115–119, 2005. © 2005 Wiley‐Liss, Inc.
Hen egg immunoglobulin Y in colloidal gold agglutination assay: comparison with rabbit immunoglobulin G
Authors: Gasparyan Vardan K.
Published: May 2005

Conjugation of immunoglobulin G (IgG) from rabbit serum with colloidal gold for sol agglutination assay was conducted. Effects of various buffer systems on conjugation and stability of sols were studied. Colloidal gold assay for detection of human myoglobin and C‐reactive protein was developed. It was shown that rabbit IgG had a poor stabilizing effect on colloidal gold sol and therefore that it cannot be effectively used in such assays. In contrast, hen egg immunoglobulin Y (IgY) had excellent stabilizing properties used in various buffer systems and in a wide range of concentrations. IgY was considered as a useful alternative for rabbit antibodies in gold sol agglutination assay. J. Clin. Lab. Anal. 19:124–127, 2005. © 2005 Wiley‐Liss, Inc.
In vivo cutaneous interferon‐γ gene delivery using novel dicationic (gemini) surfactant–plasmid complexes
Authors: Badea Ildiko , Verrall Ronald , Baca‐Estrada Maria , Tikoo Suresh , Rosenberg Alan , Kumar Praveen , Foldvari Marianna
Published: May 2005

Background

Localized scleroderma (morphea and linear scleroderma) is a connective tissue disease, accompanied by excessive proliferation and deposition of collagen within the skin, inflammation, vasculopathy and a deranged immune system. Interferon γ (IFNγ), an inhibitor of collagen synthesis and an immunomodulator, could be a potential therapeutic agent if it could be delivered into or expressed locally in affected skin in a non‐invasive manner. In this study, the feasibility of topical delivery of the IFNγ gene and expression of IFNγ were investigated in mice.

Methods

Novel dicationic (gemini) surfactant (spacer length n = 2–16; alkyl chain m = 12 or 16)–DNA complexes were formulated and characterized by circular dichroism and atomic force microscopy to select gemini analogues with the highest transfection efficiency (TE). Transfection and cellular expression of IFNγ from the bicistronic pGTmCMV.IFN‐GFP plasmid were evaluated in PAM 212 keratinocyte culture by ELISA and fluorescence microscopy. Topical delivery of plasmid using liposomal and nanoemulsion systems, based on gemini surfactant 16‐3‐16, was evaluated in mice by IFNγ expression analysis.

Results

In vitro TE was found to be dependent on the spacer length of the gemini surfactant, with the C3 spacer showing the highest activity (both 12‐3‐12 and 16‐3‐16). Both gemini cationic liposomes and gemini nanoemulsion (3 × 25 µg DNA/animal) produced significantly higher levels of IFNγ in the skin (359.4 and 607.24 pg/cm2) compared to naked DNA (135.69 pg/cm2) or a liposomal Dc‐chol formulation (82.15 pg/cm2). IFNγ expression in the lymph nodes was higher in the animals treated with gemini liposomes (422.74 pg/animal) compared to the nanoemulsion formulation (131.27 pg/animal) or the Dc‐chol formulation (82pg/animal).

Conclusions

The feasibility of topical delivery of pGTmCMV.IFN‐GFP plasmid in mice using gemini cationic surfactant based delivery systems was demonstrated. IFNγ expression after treatment with gemini–DNA formulations in the skin was 3–5‐fold higher compared to the treatment with naked DNA (p < 0.05), and 4–6‐fold higher than the Dc‐chol–DNA complex, indicating a significant advance in topical DNA delivery across intact skin in vivo. Copyright © 2005 John Wiley & Sons, Ltd.
Raman scattering study of adsorption/desorption of water from single‐walled carbon nanotubes
Authors: Sharma Suresh C. , Singh Dharmbir , Li Ying
Published: May 2005

We utilized Raman spectroscopy to investigate H2O adsorption in and desorption from single‐walled carbon nanotubes (SWCNTs). SWCNT tips were opened by known chemical methods and H2O was inserted into the tubes via capillary action over periods up to 136 h. The wavenumbers in the OH bending region of H2O increase almost exponentially with H2O treatment time. Following H2O adsorption for 136 h, Raman spectra were also measured as a function of heat‐treatment temperature. These data lead to 0.07 eV for the H2O desorption energy from SWCNTs. Copyright © 2005 John Wiley & Sons, Ltd.
Comparison of Raman spectroscopic methods for the determination of supercooled and liquid water temperature
Authors: Risović Dubravko , Furić Krešimir
Published: May 2005

Raman spectroscopy provides an efficient method for non‐contact determination of liquid water temperature with high spatial resolution. It can be also used for remote in situ determination of subsurface water temperature. The method is based on temperature‐dependent changes of the molecular OH stretching band in the Raman spectra of liquid water. These in turn are attributed to a decrease in intermolecular hydrogen‐bonding interactions with increase in temperature. Here, the results of an experimental study employing three different approaches in the determination of temperature from recorded OH stretching band in the Raman spectra of liquid and supercooled water are presented and discussed. The first two methods are based on deconvolution of the spectral band into Gaussian components whose intensities and associated specific spectral markers are temperature dependent, and the third approach is based on Raman difference spectroscopy (RDS). The presented measurements were conducted on distilled and deionized supercooled and liquid water in the temperature range between −12.5 and +32.5 °C. The results are compared in terms of linearity of response, sensitivity and accuracy. It is shown that the method based on RDS even in the supercooled temperature range provides better accuracy (the standard deviation from the true temperature is ±0.4 K) and linearity in temperature determination than more complicated methods based on Gaussian deconvolution of the OH stretching band. Copyright © 2005 John Wiley & Sons, Ltd.
Raman tensor and selection rules for a chemical vapor transport‐grown chalcopyrite single crystal
Authors: Zhang Wendong , Sang Shengbo , Xue Chenyang , Papadimitriou Dimitra
Published: May 2005

This paper reports on the Raman tensor and selection rules of a chemical vapor transport (CVT)‐grown CuGaSe2 single crystal. CVT‐CuGaSe2 has a hollow needle‐like shape with two flat faces of unequal area, (110) and (112), which involve different systems of coordinates. In order to study the Raman spectra of these systems, we probed the theory of Raman tensors and Raman selection rules. Using the MATLAB program, we calculated the Raman tensor of CuGaSe2 (D2d) and other point groups in different orthogonal systems. In addition, by applying the selection rules for Raman scattering to the observation of phonon modes from the (110) and (112) faces of CuGaSe2, we were able to assign the Raman modes at 187, 84 and 68 cm−1, which were in accord with the literature. Additionally, we found some new Raman modes. Copyright © 2005 John Wiley & Sons, Ltd.
Iridium(III) Complexes with PEO and PS Polymer Macroligands and Light‐Emitting Properties: Synthesis and Characterization
Authors: Holder Elisabeth , Marin Veronica , Kozodaev Dmitry , Meier Michael A. R. , Lohmeijer Bas G. G. , Schubert Ulrich S.
Published: May 2005

Summary: On the basis of terpyridine functionalized poly(ethylene oxide) (PEO) and poly(styrene) (PS), a series of light‐emitting iridium(III) compounds was effectively synthesized. The respective iridium(III) target compounds were prepared by grafting chloro‐bridged precursor complexes [Ir(ppy)2‐μ‐Cl]2 (ppy = phenylpyridine) and [Ir(ppy‐CHO)2‐μ‐Cl]2 (ppy‐CHO = 4‐(2‐pyridyl)benzaldehyde) onto terpyridine functionalized PEO and PS tails. 1D and 2D NMR characterization was performed revealing the expected resonances. Gel permeation chromatography (GPC) proved the stability and purity of the targeted materials. Preliminary investigations of the light‐emitting properties were carried out by standard methods such as UV‐vis and steady‐state luminescence spectroscopy. The morphology and the quality of films of these iridium(III) compounds were furthermore investigated using AFM. Improved stability on the electrode surface was illustrated using cyclic voltammetry. One of the polymer materials was compared to the neat complex, which showed quick degradation.

Green and orange light‐emitting iridium(III) complexes with two cyclometalating ligands and one terpyridine ligand with PS tails.

magnified image

Green and orange light‐emitting iridium(III) complexes with two cyclometalating ligands and one terpyridine ligand with PS tails.
Liquid chromatography‐electron ionization mass spectrometry: Fields of application and evaluation of the performance of a Direct‐EI interface
Authors: Cappiello Achille , Famiglini Giorgio , Palma Pierangela , Siviero Antonella
Published: May 2005

A comprehensive evaluation and a thorough discussion of the fields of possible applications of the Direct‐EI interface are described in this review. Direct‐EI allows the direct introduction of the effluent from a capillary HPLC column into the electron ionization (EI) ion source of a mass spectrometer. Thanks to the reduced liquid intake and an in‐source nebulizer, the interfacing process occurs smoothly and entirely into the ion source. No intermediate interfacing mechanisms of any sort are interposed between the column and the mass spectrometer, thus circumventing any undesired sample loss and minimizing the effort for instrument modification. Theoretically, any GC‐MS system can be converted into an LC‐MS for EI amenable compounds. Several parameters, crucial for a successful integration of liquid chromatography and mass spectrometry, have been considered in the evaluation of the functioning of such an interface: limit of detection, linearity of response, reproducibility, and chromatographic compatibility. Different mobile phases, also containing non‐volatile buffers, were taken into account, demonstrating an outstanding separation flexibility. The entire set of experiments was carried out at different flow rates and temperatures of the ion source. The interface behavior was also tested in real world applications, with mixtures of pesticides, hormones, nitro‐PAH, and endocrine‐disrupting compounds, allowing picogram level detection and the possibility to record library‐matchable, readily interpretable electron ionization mass spectra, for prompt compound characterization and confirmation. © 2005 Wiley Periodicals, Inc., Mass Spec Rev 24:978–989, 2005
A marker method for the solution of the damped Burgers' equation
Authors: Lewandowski Jerome L. V.
Published: May 2005

A new method for the solution of the damped Burgers' equation is described. The marker method relies on the definition of a convective field associated with the underlying partial differential equation; the information about the approximate solution is associated with the response of an ensemble of markers to this convective field. Some key aspects of the method, such as the selection of the shape function and the initial loading, are discussed in some details. The marker method is applicable to a general class of nonlinear dispersive partial differential equations. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Additive Schwarz‐type preconditioners for fourth‐order elliptic problems using Hermite cubic splines
Authors: Liu Song‐Tao
Published: May 2005

In this note, we construct the additive Schwarz‐type preconditioner for fourth‐order elliptic problems with nested subspaces from Hermite cubic splines. We prove that after the preconditioning, the system is well conditioned. The numerical evidence strongly supports our theoretical result. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Stimuli‐responsive reversible physical networks. II. Design and properties of homogeneous physical networks consisting of periodic copolymers synthesized by living cationic polymerization
Authors: Yoshida Tomohide , Kanaoka Shokyoku , Watanabe Hiroshi , Aoshima Sadahito
Published: May 2005

The design and precision synthesis of physical networks consisting of copolymers with crystallizable pendant groups are described in this work. Amphiphilic periodic, statistical, and gradient copolymers consisting of octadecyl vinyl ether (ODVE) units were synthesized via living cationic polymerization. The synthesis involved the copolymerization of ODVE and 2‐methoxyethyl vinyl ether (hydrophilic) with an 1‐(isobutoxy)ethyl acetate [CH3CH(OiBu)OCOCH3]/Et1.5AlCl1.5 initiating system in the presence of a weak Lewis base to yield copolymers with very narrow molecular weight distributions (weight‐average molecular weight/number‐average molecular weight ⋍ 1.2). All aqueous solutions of the copolymers behaved as a viscous liquid above 50 °C. When cooled below 25 °C, the solutions turned into transparent, transient physical gels (exhibiting terminal flow), regardless of the sequence distribution. Viscoelastic studies showed that a periodic copolymer gave a hard gel that was more brittle than the gels obtained from the corresponding statistical and gradient copolymers. This difference and the differences in the relaxation time and relaxation mode distribution of the copolymer gels were consistent with the sequence distributions of ODVE in the respective copolymers. These results indicate that the mechanical properties of a physical network can be controlled by the primary polymer structures. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2712‐2722, 2005
Hyperbranched polymers—All problems solved after 15 years of research?
Authors: Voit Brigitte
Published: May 2005

Fifteen years of research on hyperbranched polymers in the group of Brigitte Voit are described, with a focus first on hyperbranched polyester synthesis and then on the addition and cycloaddition reactions used for the preparation of the hyperbranched structure. The characterization of structural details and bulk, solution, and thin‐film properties is highlighted, and steps toward the elucidation of a general property profile of hyperbranched polymers are discussed. Some effects of hyperbranched polymers in reactive formulations and blends and in thin films are addressed that can lead to applications in coatings, as additives, and in microelectronics or sensorics. The great progress possible in the last years is shown, but open questions and unsolved problems are also pointed out. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2679–2699, 2005
Effects of guest microparticles on the swelling behavior of polyacrylamide gels
Authors: Suzuki A. , Okabe N. , Suzuki H.
Published: May 2005

We report the effects of guest particles on the swelling properties of bulk polyacrylamide gels. The guest particles were the spheres of poly(N‐isopropylacrylamide) gel with submicrometer diameter, which were synthesized by an emulsion‐polymerized reaction in water. Polyacrylamide gels were prepared by a free radical polymerization reaction, immobilizing the gel microparticles with different concentrations at gelation. The macroscopic swelling ratio of this hybrid gel in a cylindrical shape was measured as functions of temperature and acetone concentration. The presence of guest particles was found to strongly affect the swelling behavior in the bulk gels when the concentration of incorporated particles exceeded a threshold. The experimental results indicated that the macroscopic volume in response to the temperature change should be determined by the guest particles above the threshold. On the other hand, the hybrid gel could not evidently shrink by adding acetone when the concentration of guest particles exceeded the threshold. To make clear the distribution of guest particles in the bulk networks, the fractured surfaces of dried gels were imaged by tapping mode atomic force microscopy. The guest particles were found to aggregate in the bulk homogeneous networks to form microdomains with densely connected structure, which became larger with increasing particle concentration. The roles of bulk networks as well as guest particles on the swelling behavior of hybrid gels were qualitatively discussed on the basis of the incorporated structure of guest particles, depending on the concentration of guest particles. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1696–1704, 2005
Effect of LDPE on the thermomechanical properties of LLDPE‐based films
Authors: Niaounakis M. , Kontou E.
Published: May 2005

The present study compares the properties of five films: one film of low‐density polyethylene (LDPE), two films of linear low density polyethylenes (1‐octene comonomer)—one made by metalllocene catalyst (mLLDPE) and the other by Ziegler–Natta (zLLDPE)—and two blend films, one of mLLDPE/LDPE (film A) and the other of zLLDPE/LDPE (film B). The effect of LDPE (22% by weight) on the thermomechanical properties of LLDPE‐based films is investigated by using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and stress‐strain in the yield region measurements. The mechanical, dynamic, and thermal properties of film A are quite similar to a single component system (mLLDPE). The addition of this amount of LDPE does not affect the melting temperature of mLLDPE but it enhances its crystallinity. Film B is a rather inhomogeneous material, as opposed to film A, and its properties seem to be dependent on stretching conditions. Furthermore, the thermally activated rate process (Eyring's theory) is applied to analyze the yielding behavior of the two blend films. Double yielding manifested by film B is described with two thermally activated processes, while film A is satisfactorily described by a single process. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1712–1727, 2005
Preparation of submicron‐scale, electrospun cellulose fibers via direct dissolution
Authors: Kim Choo‐Won , Frey Margaret W. , Marquez Manuel , Joo Yong Lak
Published: May 2005

Cellulose nonwoven mats of submicron‐sized fibers (150 nm–500 nm in diameter) were obtained by electrospinning cellulose solutions. A solvent system based on lithium chloride (LiCl) and N,N‐dimethylacetamide (DMAc) was used, and the effects of (i) temperature of the collector, (ii) type of collector (aluminum mesh and cellulose filter media), and (iii) postspinning treatment, such as coagulation with water, on the morphology of electrospun fibers were investigated. The scanning electron microscopy (SEM) and X‐ray diffraction studies of as‐spun fibers at room temperature reveal that the morphology of cellulose fibers evolves with time due to moisture absorption and swelling caused by the residual salt and solvent. Although heating the collector greatly enhances the stability of the fiber morphology, the removal of salt by coagulation and DMAc by heating the collector was necessary for the fabrication of dry and stable cellulose fibers with limited moisture absorption and swelling. The presence and removal of the salt before and after coagulation have been identified by electron microprobe and X‐ray diffraction studies. When cellulose filter media is used as a collector, dry and stable fibers were obtained without the coagulation step, and the resulting electrospun fibers exhibit good adhesion to the filter media. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1673–1683, 2005
Critical buckling load of paper honeycomb under out‐of‐plane pressure
Authors: Lu Li‐Xin , Sun Ya‐Ping , Wang Zhi‐Wei
Published: May 2005

Two out‐of‐plane buckling criteria for paper honeycomb are proposed by analysing the structure properties and the collapse mechanism of paper honeycomb: these are based on the peeling strength and ring crush strength of the chipboard wall. Taking into account the orthotropic, initial deflection and large deflection properties of the chipboard wall, the two new mechanical models and the calculation methods are developed to represent the out‐of‐plane critical load of paper honeycomb. Theoretical calculations and test results show that the models are suitable for describing the collapse mechanism of paper honeycomb. The peeling strength and ring crush strength determine the critical buckling load of paper honeycomb in different stretch phases. The out‐of‐plane critical buckling load can be predicted when the two models are integrated. Copyright © 2005 John Wiley & Sons, Ltd.
Multireference Brillouin–Wigner coupled cluster (MR‐BWCC) theory applied to the H8 model: Comparison with CCSD(T) theory
Authors: Hubač I. , Mach P. , Wilson S.
Published: May 2005

Multireference Brillouin–Wigner coupled cluster theory is applied to the H8 model, a model in which the degree of quasidegeneracy is a function of a single geometrical parameter a. Using a 6‐31G basis set, multireference Brillouin–Wigner coupled cluster theory (MR‐BWCC) is applied to the H8 model as a function of a both with and without an a posteriori correction for the lack of extensivity. The resulting potential energy curve is compared with the corresponding curve obtained by the application of single reference CCSD theory (“coupled cluster singles and doubles”), and with the curve obtained after adding a perturbative estimate of the triple excitation energy component, CCSD(T). The MR‐BWCCSD, CCSD, and CCSD(T) curves are also compared with the full configuration interaction (FCI) curve defining the exact solution within the chosen basis set. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
NLO response of polymethineimine and polymethineimine/polyacetylene conformers: Assessment of electron correlation effects
Authors: Jacquemin Denis , Perpète Eric A. , André Jean‐Marie
Published: May 2005

We have studied, at the second‐order Møller–Plesset level of approximation with the 6‐31G(d) atomic basis set, the electron correlation effects on the first hyperpolarizability of increasingly long polymethineimine oligomers and alternating polymethineimine/polyacetylene copolymers showing different conformations. Both the direct (i.e., electronic) and indirect (i.e., geometric) electron correlation contributions are large and should consequently be accounted for, even for qualitative purposes. The electron correlation effects are both conformation and chain length dependent. Long alternating polymethineimine/polyacetylene copolymers present a very large first hyperpolarizabilities, especially in the all‐trans conformation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Implementation strategy and performance outcomes in related diversification
Authors: Shayne Gary Michael
Published: May 2005

Strategy research has a long‐standing interest in the performance consequences of corporate diversification. In theory, resource sharing should yield economic benefits in related multi‐business firms, but the extensive empirical research remains equivocal. To explore this paradox, this paper examines the process of implementing a related diversification strategy. Working from existing theory, a formal model is constructed that describes the process and performance implications of a related diversification move. The model is analyzed using computer simulation, and the analysis suggests that successful diversification strategies require managerial policies that maintain organization slack. In the absence of such policies, related diversification can negatively impact firm performance even when substantial synergy opportunities exist. The analysis also demonstrates, contrary to existing theory, that diversification strategies based on a very high degree of relatedness can lead to lower performance than less related strategies in some circumstances. Counter‐intuitively, extracting potential synergies may require additional investment in shared resources. Copyright © 2005 John Wiley & Sons, Ltd.
Strategic leadership and executive innovation influence: an international multi‐cluster comparative study
Authors: Elenkov Detelin S. , Judge William , Wright Peter
Published: May 2005

This study investigates the relationship of strategic leadership behaviors with executive innovation influence and the moderating effects of top management team (TMT)'s tenure heterogeneity and social culture on that relationship. Using survey data from six countries comprising three social cultures, strategic leadership behaviors were found to have a strong positive relationship with executive influence on both product–market and administrative innovations. In addition, TMT tenure heterogeneity moderated the relationship of strategic leadership behaviors with executive innovation influence for both types of innovation, while social culture moderated that relationship only in the case of administrative innovation. Copyright © 2005 John Wiley & Sons, Ltd.
Breastfeeding experience in inborn errors of metabolism other than phenylketonuria
Authors: Huner G. , Baykal T. , Demir F. , Demirkol M.
Published: May 2005

Breastfeeding has been recommended for the dietary treatment of infants with phenylketonuria, but studies documenting clinical experience in other inborn errors of metabolism are very few. Seven infants diagnosed with methylmalonyl‐CoA mutase deficiency (n=2), ornithine carbamoyltransferase deficiency (n=1), propionic acidaemia (n=1), isovaleric acidaemia (n=1), maple syrup urine disease (n=1) and glutaric acidemia type I (n=1) were tried with breastfeeding over two years. After the control of acute metabolic problems, an initial feeding period with a measured volume of expressed breast milk plus a special essential amino acid mixture was continued with breastfeeding on demand and with the addition of a special essential amino acid mixture. Two patients with methylmalonic acidaemia and one patient with glutaric acidaemia type I tolerated breastfeeding on demand very well, with good growth and metabolic control for periods of 18, 8 and 5 months, respectively. In the patient with propionic acidaemia, on‐demand breastfeeding continued for 3 months but was terminated after two acute metabolic episodes. The patient with isovaleric acidaemia had insufficiency of breast milk and formula supplementation ended with breast milk cessation. In the patient with severe ornithine carbamoyltransferase deficiency, breastfeeding was stopped owing to poor metabolic control. The patient with maple syrup urine disease also experienced problems, both in metabolic control and in insufficiency of breast milk, resulting in termination of breastfeeding. Breastfeeding of infants with inborn errors of protein catabolism is feasible, but it needs close monitoring with attention to such clinical parameters as growth, development and biochemistry, including amino acids, organic acids and ammonia.
Inhibition of energy metabolism by 2‐methylacetoacetate and 2‐methyl‐3‐hydroxybutyrate in cerebral cortex of developing rats
Authors: Rosa R. B. , Schuck P. F. , Assis D. R. de , Latini A. , Dalcin K. B. , Ribeiro C. A. J. , Ferreira G. da C. , Maria R. C. , Leipnitz G. , Perry M. L. S. , Filho C. S. Dutra , Wyse A. T. S. , Wannmacher C. M. D. , Wajner M.
Published: May 2005

Mitochondrial β‐ketothiolase and 2‐methyl‐3‐hydroxybutyryl‐CoA dehydrogenase (MHBD) deficiencies are inherited neurometabolic disorders affecting isoleucine catabolism. Biochemically, β‐ketothiolase deficiency is characterized by intermittent ketoacidosis and urinary excretion of 2‐methyl‐acetoacetate (MAA), 2‐methyl‐3‐hydroxybutyrate (MHB) and tiglylglycine (TG), whereas in MHBD deficiency only MHB and tiglylglycine accumulate. Lactic acid accumulation and excretion are also observed in these patients, being more pronounced in MHBD‐deficient individuals, particularly during acute episodes of decompensation. Patients affected by MHBD deficiency usually manifest severe mental retardation and convulsions, whereas β‐ketothiolase‐deficient patients present encephalopathic crises characterized by metabolic acidosis, vomiting and coma. Considering that the pathophysiological mechanisms responsible for the neurological alterations of these disorders are unknown and that lactic acidosis suggests an impairment of energy production, the objective of the present work was to investigate the in vitro effect of MAA and MHB, at concentrations varying from 0.01 to 1.0 mmol/L, on several parameters of energy metabolism in cerebral cortex from young rats. We observed that MAA markedly inhibited CO2 production from glucose, acetate and citrate at concentrations as low as 0.01 mmol/L. In addition, the activities of the respiratory chain complex II and succinate dehydrogenase were mildly inhibited by MAA. MHB, at 0.01 mmol/L and higher concentrations, strongly inhibited CO2 production from all tested substrates, as well as the respiratory chain complex IV activity. The other activities of the respiratory chain were not affected by these metabolites. The data indicate a marked blockage in the Krebs cycle and a mild inhibition of the respiratory chain caused by MAA and MHB. Furthermore, MHB inhibited total and mitochondrial creatine kinase activities, which was prevented by the use of the nitric‐oxide synthase inhibitor L‐NAME and glutathione (GSH). These data indicate that the effect of MHB on creatine kinase was probably mediated by oxidation or other modification of essential thiol groups of the enzyme by nitric oxide and other by‐products derived from this organic acid. In contrast, MAA did not affect creatine kinase activity. Taken together, these observations indicate that aerobic energy metabolism is inhibited by MAA and to a greater extent by MHB, a fact that may be related to lactic acidaemia occurring in patients affected by MHBD and β‐ketothiolase deficiencies. If the in vitro effects detected in the present study also occur in vivo, it is tempting to speculate that they may contribute, at least in part, to the neurological dysfunction found in these disorders.
Management of methylmalonic acidaemia by combined liver–kidney transplantation
Authors: Nagarajan S. , Enns G. M. , Millan M. T. , Winter S. , Sarwal M. M.
Published: May 2005

Methylmalonic acidaemia (MMA) is a rare autosomal recessive inborn error of metabolism that typically presents in infancy with recurrent episodes of metabolic acidosis, developmental delay and failure to thrive. The disease course is complicated by the development of chronic tubulointerstitial nephritis progressing to end‐stage renal disease in adolescence. We describe two adolescents with cobalamin‐nonresponsive MMA (mut0) who developed polyuria, chronic tubulointerstitial nephritis, dystonia but normal synthetic liver function. Both patients received combined liver–kidney transplantation (CLKT), preceded by a single pretransplant haemodialysis for clearance of methylmalonic acid. Post CLKT there was 95–97% reduction in serum and urine methylmalonic acid, leading to significant liberalization of dietary protein intake and a consequent increase in body mass index, muscle strength and energy. In addition, renal function normalized and clinical neurological status stabilized. We propose that CLKT be considered as a therapeutic option early in the course of cobalamin‐nonresponsive MMA. Progressive tubulointerstitial nephritis with disabling polyuria is a confounder in patient management even in the absence of end‐stage renal disease. Successful CLKT restores methylmalonyl‐CoA mutase enzyme levels in the liver and kidney, improves clearance of methylmalonic acid with resultant dietary protein liberalization, and offers excellent graft and patient outcomes with improvement in quality of life.
OPA3 mutation screening in patients with unexplained 3‐methylglutaconic aciduria
Authors: Neas K. , Bennetts B. , Carpenter K. , White R. , Kirk E. P. , Wilson M. , Kelley R. , Baric I. , Christodoulou J.
Published: May 2005

We have screened 13 patients with neurological abnormalities and 3‐methylglutaconic aciduria (3MGA) for mutations in the OPA3 gene, which are known to be the cause of Costeff syndrome (optic atrophy, chorea and spasticity; type III 3MGA). We aimed to explore whether mutations in the OPA3 gene are present in patients with 3MGA but without classic Costeff syndrome. OPA3 mutations (IVS1−1G>C) were identified in 2 patients with the classic phenotype of type III 3MGA, but not in the other 11 patients with differing non‐Costeff phenotypes associated with developmental delay and neurological signs and symptoms as described. We identified a previously described sequence variation in the OPA3 gene (c.231T>C) in 12/13 patients. The alteration was homozygous in 8/12 and heterozygous in 4/12. This alteration was also found in 60 of 98 normal control alleles. In a single patient, a novel sequence variation in the 5′ UTR was identified, (c.−38A>G). Our studies suggest that the c.231T>C sequence variation is of no clinical significance, whereas the significance of the 5′ UTR sequence variation remains open to speculation. Our study of the OPA3 gene in patients with 3MGA without Costeff syndrome suggests that mutations in OPA3 are not a common cause of 3MGA in the absence of signs of Costeff syndrome.