bluuebunny/crossref_metadata_2025 huggingface dataset:
An improved experimental and regression methodology for sorption isotherms
Authors: Quirijns Elisabeth J , van Boxtel Anton JB , van Loon Wilko KP , van Straten Gerrit
Published: October 2004

Sorption isotherms of corn and starch cylinders with immobilised catalase are experimentally determined at different temperatures for use in drying models in optimal control studies. This application of the sorption isotherm requires an accurate prediction of the sorption data at different temperatures for the low water activity range. The GAB equation is used for the prediction of the sorption isotherms. Two major problems are encountered by employing standard procedures, ie prediction of sorption at aw < 0.11 and sensitivity of the GAB parameters to the applied data range. An improved methodology is developed, consisting of extending the standard experimental procedure with additional data points in the low water activity range and changing the criterion in the regression procedure in the sum of squares, which is weighed by the variance of the experimental data. The new methodology leads to accurate, consistent and physically relevant parameters of the GAB equation, which are independent of the applied data range in the regression analysis and which result in accurate predictions of the sorption behaviour at low water activity. The sorption data at different temperatures at low water activity can be predicted in the best way with parameters obtained after direct regression based on weighed SSQ. Copyright © 2004 Society of Chemical Industry
Accelerated storage and isothermal microcalorimetry as methods of predicting carrot juice shelf‐life
Authors: Alklint Charlotte , Wadsö Lars , Sjöholm Ingegerd
Published: October 2004

The possibility of predicting the shelf‐life of pasteurized carrot juice by isothermal microcalorimetry or change in pH was investigated and compared with traditional plate count results. A small increase in thermal power (2 µW), maximal increase of and acceleration of thermal power all gave rapid, well‐correlated results for the shelf‐life, as did pH, during accelerated storage. The effect of accelerated storage (17 °C) on the microbial flora of pasteurized carrot juice was also compared with the flora from storage at 8 °C, and it was found that accelerated storage is feasible for the rapid evaluation of shelf‐life, but that the microbial flora in the spoilt juice will be different. Copyright © 2004 Society of Chemical Industry
Free‐radical scavenging activity of wormwood (Artemisia absinthium L) extracts
Authors: Canadanovic‐Brunet Jasna M , Djilas Sonja M , Cetkovic Gordana S , Tumbas Vesna T
Published: October 2004

In an effort to discover new antioxidant natural compounds, wormwood (Artemisia absinthium L) an aromatic‐bitter herb, was screened. The sequential extraction was realized with five solvents of different polarities (70% methanol, petroleum ether, chloroform, ethyl acetate, n‐butanol). The antioxidative activity was tested by measuring their ability to scavenge stable 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical and reactive hydroxyl radical during the Fenton reaction trapped by 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO), using electron spin resonance (ESR) spectroscopy. Results demonstrated that the antiradical and antioxidative activity depend on the type and concentration of applied extracts and increased in the order ethyl acetate > methanol > n‐butanol > chloroform > petroleum ether > remaining water extracts. The investigation showed that the antiradical activity increased with increasing concentration of all extracts. The high contents of total phenolic compounds (25.6 mg g−1) and total flavonoids (13.06 mg g−1) indicated that these compounds contribute to the antiradical and antioxidative activity. In a model system, the formation of o‐semiquinone radicals from quercetin and chlorogenic acid was obtained to prove the mechanism (hydrogen donating and/or one‐electron reduction) of free‐radical scavenging activity. Copyright © 2004 Society of Chemical Industry
Effect of the fungal protease EPg222 on proteolysis and texture in the dry fermented sausage ‘salchichón’
Authors: Benito María J , Rodríguez Mar , Córdoba María G , Andrade María J , Córdoba Juan J
Published: October 2004

Proteolytic activity of the fungal protease EPg222 and its effect on the texture of the dry fermented sausage ‘salchichón’, which has a long ripening process, was assayed. Samples with enzyme added showed a significant reduction of myofibrillar protein concentration during the ripening period, compared with a control, and proteolytic activity of the enzyme led to a higher accumulation of non‐protein and ‐amino acid nitrogen. Analysis of volatile compounds in ripened dry fermented sausages revealed that only in EPg222 batches were branched compounds derived from amino acids catabolism detected that are associated with the flavour of dry cured meat products. The texture profile analysis showed reduction in hardness, gumminess and chewiness values in treated compared with control sausages. The effect of this enzyme could be of great interest in stimulating proteolysis, in flavour development and in reducing the hardness of dry fermented sausages produced by a long ripening process. Copyright © 2004 Society of Chemical Industry
Variation in 1‐fructo‐exohydrolase (1‐FEH) and 1‐kestose‐hydrolysing (1‐KH) activities and fructo‐oligosaccharide (FOS) status in onion bulbs. Influence of temperature and storage time
Authors: Benkeblia Noureddine , Onodera Shuichi , Shiomi Norio
Published: October 2004

Effects of storage temperature and duration on 1‐fructo‐exohydrolase (1‐FEH) and 1‐kestose‐hydrolysing (1‐KH) activities and trisaccharide (Tri) and fructo‐oligosaccharide (FOS) status in onion bulbs var Tenshin kept for 24 weeks at 10 and 20 °C were investigated. 1‐FEH activity peaked sharply after 10 weeks and seemed to be triggered by a decrease in sucrose content. 1‐KH activity increased during the first 8 weeks and remained stable during the last 8 weeks. Contents of Tri, FOS and total FOS decreased abruptly during the first 8 weeks; however, at 10 °C, contents of Tri, FOS (DP 3–12) and total FOS were lower than those at 20 °C. The consumption rate of fructo‐oligosaccharides also appeared to be higher at 20 °C than at 10 °C, despite the slight degradation in activities observed at this low temperature. 1‐FEH seems to be under the control of a triggering signal which induces its activity, and sucrose seems to be this biochemical signal which initiates dormancy release and the onset of sprouting, as found previously. Thus changes in carbohydrates seem to be a strong indicator of the end of the dormant state of the bulb and the beginning of the sprouting period. Copyright © 2004 Society of Chemical Industry
ANT2 expression under hypoxic conditions produces opposite cell‐cycle behavior in 143B and HepG2 cancer cells
Authors: Chevrollier Arnaud , Loiseau Dominique , Gautier Fabien , Malthièry Yves , Stepien Georges
Published: October 2004

Under hypoxic conditions, mitochondrial ATP production ceases, leaving cells entirely dependent on their glycolytic metabolism. The cytoplasmic and intramitochondrial ATP/ADP ratios, partly controlled by the adenine nucleotide translocator (ANT), are drastically modified. In dividing and growing cells that have a predominantly glycolytic metabolism, the ANT isoform 2, which has kinetic properties allowing ATP import into mitochondria, is over‐expressed in comparison to control cells. We studied the cellular metabolic and proliferative response to hypoxia in two transformed human cell lines with different metabolic backgrounds: HepG2 and 143B, and in their ρ° derivatives, i.e., cells with no mitochondrial DNA. Transformed 143B and ρ° cells continued their proliferation whereas HepG2 cells, with a more differentiated phenotype, arrested their cell‐cycle at the G1/S checkpoint. Hypoxia induced an increase in glycolytic activity, correlated to an induction of VEGF and hexokinase II (HK II) expression. Thus, according to their tumorigenicity, transformed cells may adopt one of two distinct behaviors to support hypoxic stress, i.e., proliferation or quiescence. Our study links the constitutive glycolytic activity and ANT2 expression levels of transformed cells with the loss of cell‐cycle control after oxygen deprivation. ATP import by ANT2 allows cells to maintain their mitochondrial integrity while acquiring insensitivity to any alterations in the proteins involved in oxidative phosphorylation. This loss of cell dependence on oxidative metabolism is an important factor in the development of tumors. © 2004 Wiley‐Liss, Inc.
Motor training as treatment in focal hand dystonia
Authors: Zeuner Kirsten E. , Shill Holly A. , Sohn Young H. , Molloy Fiona M. , Thornton Bonnie C. , Dambrosia James M. , Hallett Mark
Published: October 2004

Focal hand dystonia may arise as a result of aberrant plasticity from excessive repetitive use. Improvement might be possible with appropriate motor training. Focusing on trying to decrease abnormal overflow of movement to fingers not involved in a task, we developed a motor training program for individualized finger movements. Ten patients with writer's cramp participated in the motor training program. Evaluation was done with the Fahn dystonia scale, kinematic analysis of handwriting, transcranial magnetic stimulation (TMS), and electroencephalography (EEG). Clinical improvement of dystonia was significant using the Fahn dystonia scale, and 6 patients reported an improvement in writing. The handwriting analysis showed a trend for improvement after training in simple exercises. There were no changes in cortical excitability measured by TMS and EEG. Whereas this method of motor training for 4 weeks led to mild subjective improvement and some improvement in handwriting, it is not sufficient to reverse motor cortex abnormalities measured by TMS and EEG. Published 2004 John Wiley & Sons
Acute neuropathy mimicking porphyria induced by aminolevulinic acid during photodynamic therapy
Authors: Sylantiev Constantin , Schoenfeld Nili , Mamet Rivka , Groozman Galina B. , Drory Vivian E.
Published: October 2004

An 82‐year‐old man developed severe, acute, predominantly motor polyneuropathy, signs of autonomic involvement, and skin changes following aminolevulinic acid (ALA) administration. The compound was used as a prodrug for photodynamic therapy of Barrett's esophagitis. Changes were observed in various parameters of the heme pathway. The case reported represents a rare response to ALA treatment, resembling an acute attack of hepatic porphyria with neurological features. Muscle Nerve, 2005
Effects of alcohol on skeletal and cardiac muscle
Authors: Urbano‐Márquez Alvaro , Fernández‐Solà Joaquim
Published: October 2004

The acute and chronic toxic effects of alcohol on skeletal and cardiac muscle are clinically important. Muscle weakness and atrophy are the main manifestations of skeletal myopathy, and arrhythmias and progressive left‐ventricular dysfunction are those of cardiomyopathy. Most patients remain asymptomatic from these effects for a long time. Myocyte atrophy and death are the main pathological findings. A clear dose‐related effect has been established with ethanol consumption, with gender and some specific gene polymorphisms being factors of increased susceptibility to alcohol‐induced muscle damage. Pathogenic mechanisms are pleiotropic, the most relevant being disturbances in carbohydrate, protein, and energy cell turnover, signal transduction, and induction of apoptosis and gene dysregulation. Ethanol abstinence is the only effective treatment, although controlled drinking is useful in patients who do not achieve abstinence. Persistent high‐dose consumption results in deterioration of muscle and heart function, with a high mortality due to arrhythmias and progression of heart failure. Muscle Nerve, 2004
First report of overactive detrusor in association with hypospadias detected by urodynamic screening
Authors: Ozkurkcugil Cuneyd , Guvenc B. Haluk , Dillioglugil Ozdal
Published: October 2004

Aims

The purpose of this study was to determine urodynamic features in hypospadic patients.

Methods

Thirty‐seven patients with hypospadias (distal: 31, proximal: 6) underwent preoperative urodynamic study according to International Continence Society (ICS) recommendations. Statistical analysis were done for comparison between urethral obstruction and non‐obstruction in patients with detrusor overactivity (DO) plus the relationship of DO with localization of hipospadias.

Results

Nearly 45.9% of the patients showed overactive detrusor. Urethral obstruction was found in 60.8% of the patients. The rate of DO was higher in proximal hipospadias, and urethral obstruction than distal type, and non‐obstructed patients (P > 0.005). The means overall cystometric capacity, maximum voiding detrusor pressure and maximal urinary flow measured were 132.6 ± 111.14 ml (range 21–610), 72 ± 53 cmH2O (range 12–181), and 7.9 ± 7.1 ml/sec (range 2–30 ml/sec), respectively.

Conclusions

To the best of our knowledge, this is the first study ever to show that overactive detrusor is an accompanying entity in the hypospadic patients. © 2004 Wiley‐Liss, Inc.
The Hungarian method for the assignment problem
Authors: Kuhn H. W.
Published: October 2004

This paper has been presented with the Best Paper Award. It will appear in
print in Volume 52, No. 1, February 2005.
A network flow approach to cost allocation for rooted trees
Authors: Iwata Satoru , Zuiki Nozomu
Published: October 2004

In the game theory approach to cost allocation, the main computational issue is an algorithm for finding solutions such as the Shapley value and the nucleolus. In this article, we consider the problem of allocating the maintenance cost of a tree network that connects the supply source at the root to the users at the leaves. We show that the core of the game can be expressed in terms of network flows. Based on this observation, we present O(n log n) algorithms for computing the nucleolus and the egalitarian allocation. © 2004 Wiley Periodicals, Inc. NETWORKS, Vol. 44(4), 297–301 2004
Population density regulates Drosophila synaptic morphology in a Fasciclin‐II‐dependent manner
Authors: Stewart Bryan A. , McLean Jesse R.
Published: October 2004

Genetic analysis of the Drosophila larval neuromuscular junction has identified some of the key molecules that regulate synaptic plasticity. Among these molecules, the expression level of Fasciclin II (FasII), a homophilic cell adhesion molecule, is critically important for determining the final form of the neuromuscular junction. Genetic reduction of FasII expression by 50% yields more elaborate nerve terminals, while a greater reduction in expression, to 10% of wild‐type, yields a substantial reduction in the nerve terminal morphology. Importantly, regulation of FasII expression seems to be the final output for several genetic manipulations that transform NMJ morphology. In an effort to understand the importance of this regulatory pathway in the normal animal, we have undertaken studies to identify environmental cues that might be important for initiating FasII‐dependent changes in synaptic plasticity. Here we report on the relationship between larval population density and synaptic morphology, synaptic strength, and FasII levels. We raised Drosophila larvae under conditions of increasing population density and found an inverse exponential relationship between population density and the number of synaptic boutons, the number of branches, and the length of branches. We also observed population‐dependent alteration in FasII levels, with lower densities having less FasII at the synapse. The correlation between density and morphological change was abrogated in larvae constitutively expressing FasII, and in wild‐type larvae grown on soft culture medium. Together these data show that environmental cues can induce regulation of FasII. Interestingly, however, the quantal content of synaptic transmission was not different among the different population densities, suggesting that other factors contribute to maintaining synaptic strength at a defined level. © 2004 Wiley Periodicals, Inc. J Neurobiol, 2004
A FETI‐based multi‐time‐step coupling method for Newmark schemes in structural dynamics
Authors: Prakash A. , Hjelmstad K. D.
Published: October 2004

We present an efficient and accurate multi‐time‐step coupling method using FETI domain decomposition for structural dynamics. Using this method one can divide a large structural mesh into a number of smaller subdomains, solve the individual subdomains separately and couple the solutions together to obtain the solution to the original problem. The various subdomains can be integrated in time using different time steps and/or different Newmark schemes. This approach will be most effective for very large‐scale simulations on complex geometries.

Our coupling method builds upon a method previously proposed by Gravouil and Combescure (GC method). We show that for the simplest case when the same time step is used in all subdomains of the mesh our method reduces to the GC method and is unconditionally stable and energy preserving. In addition, we show that our method possesses these desirable properties for general multi‐time‐step cases too unlike the GC method which is dissipative. Greater computational efficiency is also achieved through our method by limiting the computation of interface forces to the largest time step as opposed to the smallest time step in the GC method. Copyright © 2004 John Wiley & Sons, Ltd.
Higher‐order extensions of a discontinuous Galerkin method for mid‐frequency Helmholtz problems
Authors: Farhat Charbel , Tezaur Radek , Weidemann‐Goiran Paul
Published: October 2004

Recently, a discontinuous Galerkin method with plane wave basis functions and Lagrange multiplier degrees of freedom was proposed for the efficient solution of Helmholtz problems in the mid‐frequency regime. In this paper, this method is extended to higher‐order elements. Performance results obtained for various two‐dimensional problems highlight the advantages of these elements over classical higher‐order Galerkin elements such as Q2 and Q4 for the discretization of interior and exterior Helmholtz problems. Copyright © 2004 John Wiley & Sons, Ltd.
A stabilized one‐point integrated quadrilateral Reissner–Mindlin plate element
Authors: Gruttmann F. , Wagner W.
Published: October 2004

A new quadrilateral Reissner–Mindlin plate element with 12 element degrees of freedom is presented. For linear isotropic elasticity a Hellinger–Reissner functional with independent displacements, rotations and stress resultants is used. Within the mixed formulation the stress resultants are interpolated using five parameters for the bending moments and four parameters for the shear forces. The hybrid element stiffness matrix resulting from the stationary condition can be integrated analytically. This leads to a part obtained by one‐point integration and a stabilization matrix. The element possesses a correct rank, does not show shear locking and is applicable for the evaluation of displacements and stress resultants within the whole range of thin and thick plates. The bending patch test is fulfilled and the computed numerical examples show that the convergence behaviour is better than comparable quadrilateral assumed strain elements. Copyright © 2004 John Wiley & Sons, Ltd.
Optimal design and optimal control of structures undergoing finite rotations and elastic deformations
Authors: Ibrahimbegovic A. , Knopf‐Lenoir C. , Kučerová A. , Villon P.
Published: October 2004

In this work, we deal with the optimal design and optimal control of structures undergoing large rotations and large elastic deformations. In other words, we show how to find the corresponding initial configuration through optimal design or the corresponding set of multiple load parameters through optimal control, in order to recover a desired deformed configuration or some desirable features of the deformed configuration as specified more precisely by the objective or cost function. The model problem chosen to illustrate the proposed optimal design and optimal control methodologies is the one of geometrically exact beam. First, we present a non‐standard formulation of the optimal design and optimal control problems, relying on the method of Lagrange multipliers in order to make the mechanics state variables independent from either design or control variables and thus provide the most general basis for developing the best possible solution procedure. Two different solution procedures are then explored, one based on the diffuse approximation of response function and gradient method and the other one based on genetic algorithm. A number of numerical examples are given in order to illustrate both the advantages and potential drawbacks of each of the presented procedures. Copyright © 2004 John Wiley & Sons, Ltd.
Sounding of finite solid bodies by way of topological derivative
Authors: Bonnet Marc , Guzina Bojan B.
Published: October 2004

This paper is concerned with an application of the concept of topological derivative to elastic‐wave imaging of finite solid bodies containing cavities. Building on the approach originally proposed in the (elastostatic) theory of shape optimization, the topological derivative, which quantifies the sensitivity of a featured cost functional due to the creation of an infinitesimal hole in the cavity‐free (reference) body, is used as a void indicator through an assembly of sampling points where it attains negative values. The computation of topological derivative is shown to involve an elastodynamic solution to a set of supplementary boundary‐value problems for the reference body, which are here formulated as boundary integral equations. For a comprehensive treatment of the subject, formulas for topological sensitivity are obtained using three alternative methodologies, namely (i) direct differentiation approach, (ii) adjoint field method, and (iii) limiting form of the shape sensitivity analysis. The competing techniques are further shown to lead to distinct computational procedures. Methodologies (i) and (ii) are implemented within a BEM‐based platform and validated against an analytical solution. A set of numerical results is included to illustrate the utility of topological derivative for 3D elastic‐wave sounding of solid bodies; an approach that may perform best when used as a pre‐conditioning tool for more accurate, gradient‐based imaging algorithms. Despite the fact that the formulation and results presented in this investigation are established on the basis of a boundary integral solution, the proposed methodology is readily applicable to other computational platforms such as the finite element and finite difference techniques. Copyright © 2004 John Wiley & Sons, Ltd.
Tumor response and toxicity with multiple infusions of high dose 131I‐MIBG for refractory neuroblastoma
Authors: Howard James P. , Maris John M. , Kersun Leslie S. , Huberty John P. , Cheng Su‐Chun , Hawkins Randall A. , Matthay Katherine K.
Published: October 2004

Background

131I Metaiodobenzylguanidine (131I‐MIBG) is an effective targeted radiotherapeutic for neuroblastoma with response rates greater than 30% in refractory disease. Toxicity is mainly limited to myelosuppression. The aim of this study was to determine the response rate and hematologic toxicity of multiple infusions of 131I‐MIBG.

Procedure

Patients received two to four infusions of 131I‐MIBG at activity levels of 3–19 mCi/kg per infusion. Criteria for subsequent infusions were neutrophil recovery without stem cell support and lack of disease progression after the first infusion.

Results

Sixty‐two infusions were administered to 28 patients, with 24 patients receiving two infusions, two patients receiving three infusions, and two patients receiving four infusions. All patients were heavily pre‐treated, including 16 with prior myeloablative therapy. Eleven patients (39%) had overall disease response to multiple therapies, including eight patients with measurable responses to each of two or three infusions, and three with a partial response (PR) after the first infusion and stable disease after the second. The main toxicity was myelosuppression, with 78% and 82% of patients requiring platelet transfusion support after the first and second infusion, respectively, while only 50% had grade 4 neutropenia, usually transient. Thirteen patients did not recover platelet transfusion independence after their final MIBG infusion; stem cell support was given in ten patients.

Conclusions

Multiple therapies with 131I‐MIBG achieved increasing responses, but hematologic toxicity, especially to platelets, was dose limiting. More effective therapy might be given using consecutive doses in rapid succession with early stem cell support. © 2004 Wiley‐Liss, Inc.
A young girl with hemolytic anemia and elevated hemoglobin F
Authors: Parikh Nehal S. , Hoyer James D. , Cripe Timothy P.
Published: October 2004

The non‐immune, non‐spherocytic anemias result from multiple potential etiologies. We report a 16‐year‐old girl, who was presented with a long‐standing anemia and normal blood screening tests except an elevated hemoglobin F. Her diagnosis of unstable hemoglobinopathy was made only after gene sequencing of the β‐globin chain. © 2004 Wiley‐Liss, Inc.
Benzylpenicillin cleavage with polyelectrolytes
Authors: Arcelli Antonio , Cecchi Romina , Porzi Gianni , Sandri Monica
Published: October 2004

Kinetic studies of the aminolysis of benzylpenicillin (BP) in poly(ethylenimine) (PEI) showed a complicated rate behaviour owing to the strong substrate–polyelectrolyte interaction. The results were interpreted by the formation of an unreactive and reactive complex which is converted into the poly(ethylenimine)penicilloylamide. In the presence of KCl the PEI behaves as a simple amine and the second‐order rate constants (kN) of the nucleophilic attack on β‐lactam were calculated at various pH values. The Brønsted β value is consistent with a stepwise mechanism in which the rate‐determining step is the T± intermediate decomposition in absence of general acid–base catalysis. The PEI reveals its catalytic ability not only by binding the substrate to the polymer, but also by increasing the reactivity of the reactive complex. A negligible effect on the alkaline hydrolysis of BP was found in the presence of poly(diallyldimethylammonium) chloride (PDDA). A parallel between PEI and human serum albumin (HSA) in the BP aminolysis is proposed. Copyright © 2004 John Wiley & Sons, Ltd.
γ‐Irradiation of ultrahigh‐molecular‐weight polyethylene: Electron paramagnetic resonance and nuclear magnetic resonance spectroscopy and imaging studies of the mechanism of subsurface oxidation
Authors: Alam Todd M. , Celina Mathew , Collier John P. , Currier Barbara H. , Currier John H. , Jackson Simon K. , Kuethe Dean O. , Timmins Graham S.
Published: October 2004

The shelf aging of irradiated ultrahigh‐molecular‐weight polyethylene (UHMWPE) causes subsurface oxidation, which leads to failure in UHMWPE orthopedic components, yet the mechanisms causing subsurface oxidation remain unclear. The shelf aging of γ‐irradiated UHMWPE bars has been studied with electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) imaging and with microtoming and Fourier transform infrared microscopy. The bars initially contained only allyl radicals, and upon air exposure, a surface layer of peroxyl radicals formed through the reaction of allyl radicals with oxygen. Importantly, a band of low radical intensity just beneath the peroxyl layer became apparent. NMR imaging showed a zone of altered proton relaxation in this zone. With increasing time, surface peroxyl radicals persisted in comparison with the interior allyl radicals, although oxygen did not appear to penetrate any more deeply into the bar. The area of maximal oxidation and mechanical disruption, measured after 3 years, was at the interface between the zone of exterior peroxyl radicals and the zone of low radical intensity. We present a mechanism involving the intermediacy of sterically strained reactive dialkyl peroxides at this interface to explain subsurface oxidation. We also demonstrate that EPR and NMR imaging provides information that could potentially be used to identify subsurface oxidized UHMWPE components before failure. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5929–5941, 2004
Preparation and properties of novel benzoxazine and polybenzoxazine with maleimide groups
Authors: Liu Ying‐Ling , Yu Juin‐Meng , Chou Ching‐I
Published: October 2004

A benzoxazine compound with a maleimide group, 3‐phenyl‐3,4‐dihydro‐2H‐6‐(N‐maleimido)‐1,3‐benzoxazine (HPM‐Ba), was prepared from N‐(4‐hydroxyphenyl)maleimide, formaldehyde, and aniline. The chemical structure of HBM‐Ba was identified by FT‐IR, 1H‐NMR, and elemental analysis. HPM‐Ba showed a melting point of 52–55 °C and good solubility in common organic solvents. HPM‐Ba showed a two‐stage process of thermal polymerization. The first stage arose from the polymerization of maleimide groups, and the second one was the ring‐opening reaction of benzoxazine groups. Fusible polymaleimides with a Tg of around 100 °C could be obtained by thermally polymerizing HPM‐Ba at 130 °C. Further polymerizing the polymaleimides at 240 °C resulted in a completely cured resin showing a Tg at 204 °C. Good thermal stability and self‐extinguishing behavior was observed with the cured polybenzoxazine resins. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5954–5963, 2004
Synthesis and characterization of cellulose derivatives prepared in NaOH/urea aqueous solutions
Authors: Zhou Jinping , Zhang Lina , Deng Qinghai , Wu Xiaojun
Published: October 2004

We successfully synthesized hydroxypropylcellulose (HPC) and methylcellulose (MC) in high yields from cellulose in 6 wt % NaOH/4 wt % urea aqueous solutions at 25 °C. The cellulose derivatives were characterized with NMR, size exclusion chromatography/laser light scattering, gas chromatography (GC), ultraviolet, and solubility measurements in different solvents. According to the results of solution13C NMR and GC, the individual degree of substitution (DS; i.e., the average number of substituted hydroxyl groups in the monomer unit) at C‐2 hydroxyl groups was slightly higher than the DS values at C‐3 and C‐6 hydroxyl groups for HPC and MC. In comparison with traditional systems, NaOH/urea aqueous solutions were proved to be a stable and more homogeneous reaction medium for preparing cellulose ether with a more uniform microstructure. The low limits for the average number of moles of the substituent groups per monomer unit and the DS value of water‐soluble HPC were 1.03 and 0.85, respectively. MC (DS = 1.48) had good solubility in both water and organic solvents, and the precipitation point occurred at about 67 °C for a 2% (w/v) aqueous solution. In this way, we could provide a simple, pollution‐free, and homogeneous aqueous solution system for synthesizing cellulose ethers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5911–5920, 2004
Polymers based on benzyl methacrylate: Synthesis via atom transfer radical polymerization, characterization, and thermal stabilities
Authors: Demirelli Kadir , Coskun Mehmet , Kaya Esin
Published: October 2004

Copolymerization and homopolymerization of benzyl methacrylate (BMA) and ethyl methacrylate (EMA) by the atom transfer radical polymerization method (ATRP) were performed at 90 °C. ATRP of BMA was also carried out at 80, 100, and 110 °C. The number‐average molecular weight (Mn) and polydispersities decreased with temperature. When BMA units increased in the copolymer system, the Mn values and polydispersities decreased (1.63 < Mw/Mn < 1.13). The homopolymers and poly(BMA‐co‐EMA) were characterized by Fourier transform infrared (FTIR), 1H and 13C NMR, and gel permeation chromatography (GPC) techniques. The compositions of the copolymers were calculated from 1H NMR spectra. For the atom transfer radical copolymerization system, their monomer reactivity ratios were obtained by using the Kelen–Tüdös equation, as r1 = 0.812, r2 = 1.162 (r1 is the monomer reactivity ratio of BMA). The initial decomposition temperatures of the resultant copolymers decrease with an increasing mol fraction of BMA, which indicates that the heat resistance of the copolymer has been improved by decreasing the BMA units. Blends of poly(BMA) and poly(EMA) obtained via the ATRP method have been prepared by casting films from a dichlorormethane solution. The blends have been characterized by differential scanning calorimetry and thermogravimetry. The measurements were comparable with those of copolymers synthesized. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5964–5973, 2004
Crystallization behavior and morphology of poly(ethylene‐co‐trimethylene terephthalate)s
Authors: Wu Tzong‐Ming , Lin Yen‐Wen
Published: October 2004

The melt crystallization behaviors and crystalline structures of poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate), and poly(ethylene‐co‐trimethylene terephthalate) (PETT) were investigated with differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X‐ray diffraction at various crystallization temperatures (Tcs). The PETT copolymers were synthesized via the polycondensation of terephthalate with ethylene glycol and trimethylene glycol (TG) in various compositions. The copolymers with 69.0 mol % or more TG or 31.0 mol % or less TG were crystallizable, but the other copolymers containing 34–56 mol % TG were amorphous. The DSC isothermal results revealed that the addition of a small amount of flexible TG (up to 21 mol %) to the PET structure slightly reduced the formation of three‐dimensional spherulites. A greater TG concentration (91–100%) in the copolyesters changed the crystal growth from two‐dimensional to three‐dimensional. The DSC heating scans after the completion of isothermal crystallization at various Tcs showed three melting endotherms for PET, PETT‐88, PETT‐84, and PETT‐79 and four melting endotherms for PETT‐9 and PETT. The presence of an additional melting endotherm could be attributed to the melting of thinner and imperfect copolyester crystallites. Analyses of the Lauritzen–Hoffman equation demonstrated that PETT‐88 had the highest values of the product of the lateral and folding surface free energies, and this suggested that the addition of small amounts of flexible trimethylene terephthalate segments to PET disturbed chain regularity, thus increasing molecular chain mobility. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4255–4271, 2004
A density functional method for the calculation of the zero‐voltage conductance of molecular electronic devices
Authors: Ernzerhof Matthias , Zhuang Min
Published: October 2004

Molecular electronics poses a new challenge to density functional theory. The key property of molecular electronic devices is their conductance g. Here we propose a new strategy for the calculation of g employing Kohn–Sham density functional theory. We illustrate our approach by studying the conductance of short gold wires that are one atom in diameter. In agreement with recent experiments, we obtain conductance variations with the number of atoms in the wire. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Rider's net moment estimation using control force of motion system for bicycle simulator
Authors: Shin Jae‐Cheol , Lee Chong‐Won
Published: October 2004

One of the challenging problems with bicycle simulators is to deal with the virtual bicycle dynamics that is coupled with rider's motion. For the virtual bicycle dynamics calculation and the real time simulation, it is necessary to identify the control inputs from the rider as well as the virtual environments. The steering, pedaling, and braking torques can be easily measured by using torque sensors and the virtual environments can be generated and provided by a visual system. However, direct measurement of the rider's net moment that significantly affects the bicycle motion is not practical. In this work, it is shown that six control forces of the Stewart platform‐based motion system can be used for effective estimation of the rider's net moment, incorporated with the sliding mode controller with perturbation estimation. © 2004 Wiley Periodicals, Inc.
CAD‐based automated robot programming in adhesive spray systems for shoe outsoles and uppers
Authors: Kim J. Y.
Published: October 2004

Most shoe manufacturing processes are not yet automated; it puts restrictions on increasing productivity. Among them, adhesive application processes particularly are holding the most workers and working hours. In addition, the working environment is very poor due to the toxicity of adhesive agents. In the case of automating an adhesive application process by using a robot, robot teaching by playback is difficult to produce high productivity because the kinds of shoes to be taught mount up to several thousands. To cope with it, it is necessary to generate robot working paths automatically according to the kind, the size, or the right and the left of shoes, and also to teach the generated paths to a robot automatically. This paper presents a method to generate three‐dimensional robot working paths off‐line based on CAD data in an automatic adhesive spray system for shoe outsoles and uppers. First, this paper describes how to extract the three‐dimensional data of an outsole outline from a two‐dimensional CAD drawing file. Second, it describes how to extract the three‐dimensional data of an upper profiling line from the three‐dimensional scanning data that is opened in a three‐dimensional CAD program. Third, it describes how to generate robot working paths based on the extracted data and the nozzle setting parameters for adhesive spray. Also, a series of experiments for adhesive spray is performed to verify the effectiveness of the presented methods. This study will do much for increasing productivity in shoe manufacturing as a core work of a robotic adhesive spray system. © 2004 Wiley Periodicals, Inc.
Human capital and learning as a source of sustainable competitive advantage
Authors: Hatch Nile W. , Dyer Jeffrey H.
Published: October 2004

This paper seeks to identify the sources of wide and persistent variations in learning performance in the semiconductor manufacturing industry. In the resource‐based view of the firm, human capital is frequently assumed to contribute to competitive advantage due to its inimitability based on its intangible, firm‐specific, and socially complex nature. Consistent with this view, we find that investments in firm‐specific human capital have a significant impact on learning and firm performance. More specifically, human capital selection (education requirements and screening), development through training, and deployment significantly improve learning by doing, which in turn improves performance. However, we find that acquiring human capital with prior industry experience from external sources significantly reduces learning performance. We also find that firms with high turnover significantly underperform their rivals, revealing the time‐compression diseconomies that protect firm‐specific human capital from imitation. These results provide new empirical evidence of the inimitability of human capital. Copyright © 2004 John Wiley & Sons, Ltd.
Ownership structure and firm value: new evidence from Spain
Authors: de Miguel Alberto , Pindado Julio , de la Torre Chabela
Published: October 2004

This paper provides new evidence on the way in which ownership influences firm value. Unlike previous studies, the empirical evidence obtained from our ownership concentration model supports not only the monitoring but also the expropriation effects. Additionally, the insider ownership model provides results that confirm the convergence‐of‐interest and the entrenchment effects, even though Spanish insiders get entrenched at higher ownership levels than their U.S. and U.K. counterparts. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of market cycle on the performance of Singapore acquirers
Authors: Pangarkar Nitin , Lie Junius R.
Published: October 2004

In this paper, we hypothesize that acquisitions undertaken during low market cycles will exhibit better performance than other acquisitions for two key reasons: lower likelihood of overpayment due to hubris and ease in implementing restructuring initiatives such as retrenchment. We define performance as the cumulative abnormal returns surrounding the acquisition event and deploy a trend‐based measure for market cycle. Based on an analysis of 115 acquisitions by Singapore firms between 1990 and 1999, we find strong support for the hypothesized relationship. Copyright © 2004 John Wiley & Sons, Ltd.
Optical Properties of Nanoparticle‐Based Metallodielectric Inverse Opals
Authors: Wang Dayang , Li Jensen , Chan C. T. , Salgueiriño‐Maceira Verónica , Liz‐Marzán Luis M. , Romanov Sergei , Caruso Frank
Published: October 2004

Metallodielectric inverse opals were prepared by co‐crystallizing silica‐coated gold nanoparticles and polymer spheres, followed by removal of the crystal template. The inverse opals exhibit a distinct reflectance peak, which results from Bragg diffraction due to the highly ordered 3D macroporous structure. Photonic band‐structure calculations indicate that the characteristic reflectance peaks observed are signatures of the directional gap at the L point. It is demonstrated that the optical properties (the position and magnitude of the electromagnetic bandgaps) of the gold–silica nanocomposite inverse opals can be engineered by varying the nanoparticle morphology (core size and shell thickness) and/or the nanoparticle volume‐filling ratio of the composite. The use of metallodielectric nanoparticles to form inverse opals offers a versatile approach to prepare photonic materials that may exhibit absolute bandgaps.
Optimizing the Treatment of AMES High‐risk Papillary Thyroid Carcinoma
Authors: Lo Chung‐Yau , Chan Wai‐Fan , Lam King‐Yin , Wan Koon‐Yat
Published: October 2004

A minority of patients with papillary thyroid carcinoma (PTC) is at high‐risk of developing recurrent disease and death. Risk group stratification as defined by age, metastases to distant site, extrathyroidal invasion, and tumor size (AMES) criteria is frequently employed to identify high‐risk patients for aggressive surgical and adjuvant treatments. The present study aimed at evaluating risk factors and the impact of treatment on cause‐specific mortality (CSM) in this group of high‐risk patients. From 1961 to 2000, 150 of 499 patients surgically treated for PTC were considered as high‐risk by AMES criteria. At 10‐years CSM was significantly higher in high‐risk patients (28%) than in low‐risk patients (2%) (p< 0.0001). The clinicopathologic features, treatment, and outcome of AMES high‐risk patients were retrospectively studied and risk factors for CSM were analyzed. There were 58 men and 92 women with a median age of 62 years (range: 18–87 years). Bilateral thyroidectomy was performed for 143 (95%) patients and concomitant neck dissection was performed for 82 patients (55%). Thirty‐six patients (24%) underwent incomplete tumor excision with residual disease. Radioactive iodine (I131) ablation and external‐beam irradiation were administered to 102 (68%) and 46 patients (31%), respectively. Over a median follow‐up of 7.6 years, the overall mortality was 23% and 44%, whereas the CSM was 14% and 28% at 5 and 10 years, respectively. Using the Cox proportional hazard model, distant metastasis at presentation, incomplete tumor excision, and no postoperative I131treatment were independent prognostic factors of poor survival. Patients who underwent an incomplete excision showed improved survival after I131ablation (p= 0.0008), external‐beam irradiation (p= 0.02), or both forms of treatment (p= 0.04). Within this high‐risk AMES group, International Union Against Cancer (UICC) pTNM staging and MACIS (Metastasis, Age, Completeness, Invasion, Size) scoring correlated significantly with CSM. AMES high‐risk PTC patients should undergo total thyroidectomy aiming at complete tumor resection followed by I131ablation. External‐beam irradiation should be added for patients with residual disease after an incomplete excision.
Long‐term Survival of Patients with Small Intestinal Carcinoid Tumors
Authors: Zar Niklas , Garmo Hans , Holmberg Lars , Rastad Jonas , Hellman Per
Published: October 2004

Midgut carcinoid tumors are rare and have a markedly better prognosis than adenocarcinoma in the small intestine. New diagnostic methods and medical as well as surgical therapies have evolved during the last decades, leading to more active care of these patients. Patients with small intestinal carcinoids diagnosed from 1960 to 2000 in the duodenum (n= 89) and jejunum/ileum (n= 2437) were identified in the Swedish Cancer Registry. Cases without histologic verification and autopsy cases were excluded. Overall, cause‐specific and relative survival were calculated. The overall 5‐, 10‐, and 15 year survivals were, respectively, 60%, 46%, and 28% for duodenal tumors and 56%, 36%, and 23% for jejunal/ileal tumors. Cause‐specific 5‐, 10‐, and 15‐year survival was 94% for all three follow‐up periods for duodenal tumors and 87%, 80%, and 77% for those in the jejunum/ileum. The corresponding relative survivals were, respectively, 72%, 67%, and 51% for duodenal tumors and 67%, 54%, and 44% for those in the jejunum/ileum. Sex did not influence overall or cause‐specific survival. The age at diagnosis correlated inversely with overall and cause‐specific survival for tumors in the jejunum/ileum. For tumors in the jejunum/ileum, the overall and cause‐specific survival correlated with the time period of diagnosis, with a more favorable prognosis for those diagnosed in recent years. A multivariate Cox proportional hazards model showed similar results. We concluded that young age and diagnosis in recent years are positive predictors of survival for patients with midgut carcinoids. The divergence between cause‐specific and relative survival implies the need for a more detailed analysis of the causes of death of these patients.