bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequential parametric optimization of lipase production by a mutant strain Rhizopus sp. BTNT‐2
Authors: Bapiraju K. V. V. S. N. , Sujatha P. , Ellaiah P. , Ramana T.
Published: July 2005

Lipase production by the mutant strain Rhizopus sp. BTNT‐2 was optimized in submerged fermentation. Different chemical and physical parameters such as carbon sources, nitrogen sources, oils, inoculum level, pH, incubation time, incubation temperature and aeration have been extensively studied to increase lipase productivity. Potato starch (1.25% w/v) as a carbon source, corn steep liquor (1.5% w/v) as a nitrogen source and olive oil (0.5% v/v) as lipid source were found to be optimal for lipase production. The optimal levels of other parameters are 4 ml of inoculum (2.6 × 108 spores/ml), initial pH of 5.5, incubation time of 48 hours, incubation temperature of 28 °C and aeration rate of 120 rpm. With the optimized parameters, the highest production of lipase was 59.2 U/ml while an yield of only 28.7 U/ml was obtained before optimization resulting in 206% increase in the productivity. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Pollen analyses from a 50 000‐yr rodent midden series in the southern Atacama Desert (25° 30′ S)
Authors: Maldonado Antonio , Betancourt Julio L. , Latorre Claudio , Villagran Carolina
Published: July 2005

Precipitation in northern Chile is controlled by two great wind belts—the southern westerlies over the southern Atacama and points south (> 24° S) and the tropical easterlies over the northern and central Atacama Desert (16–24° S). At the intersection of these summer and winter rainfall regimes, respectively, is a Mars‐like landscape consisting of expansive surfaces devoid of vegetation (i.e. absolute desert) except in canyons that originate high enough to experience runoff once every few years. Pollen assemblages from 39 fossil rodent middens in one of these canyons, Quebrada del Chaco (25° 30′ S), were used to infer the history of vegetation and precipitation at three elevations (2670–2800 m; 3100–3200 m; 3450–3500 m) over the past 50 000 years. When compared to modern conditions and fossil records to the north and south, the pollen evidence indicates more winter precipitation at > 52, 40–33, 24–17 k cal. yr BP, more precipitation in both seasons at 17–14 k cal. yr BP, and more summer precipitation from 14–11 k cal. yr BP. Younger middens are scarce at Quebrada del Chaco, and the few Holocene samples indicate hyperarid conditions comparable to today. The only exception is a pollen assemblage that indicates a brief but significant interlude of increased winter precipitation in the last millennium. Copyright © 2005 John Wiley & Sons, Ltd.
A 20‐ka climate record from Central Himalayan loess deposits
Authors: Pant R. K. , Basavaiah N. , Juyal N. , Saini N. K. , Yadava M. G. , Appel E. , Singhvi A. K.
Published: July 2005

The southwest monsoon that dominated Central Himalaya has preserved loessic silt deposits preserved in patches that are proximal to periglacial areas. The occurrence of such silts suggests contemporary prevalence of cold and dry northwesterly winds. Field stratigraphy, geochemistry, mineral magnetism, infrared stimulated luminescence (IRSL) and radiocarbon dating has enabled reconstruction of an event chronology during the past 20 ka. Three events of loess accretion could be identified. The first two events of loess deposition occurred betweem 20 and 9 ka and were separated by a phase of moderate weathering. Pedogenesis at the end of this event gave rise to a well‐developed soil that was bracketed around 9 to > 4 ka. This was followed by the third phase of loess accretion that occurred around 4 to > 1 ka. Episodes of loess deposition and soil formation are interpreted in terms of changes in the strength of the Indian southwest monsoon. Copyright © 2005 John Wiley & Sons, Ltd.
Development of high‐performance liquid chromatographic determination of salicylaldehyde isonicotinoyl hydrazone in rabbit plasma and application of this method to an in vivo study
Authors: Kovaříková Petra , Klimeš Jiří , Štěrba Martin , Popelová Olga , Mokrý Milan , Geršl Vladimír , Poňka Přemysl
Published: July 2005

An analytical methodology appropriate for the determination of the novel drug candidate salicylaldehyde isonicotinoyl hydrazone (SIH) in rabbit plasma has been developed and validated. Desirable chromatographic separation was achieved on a C18 column employing a mixture of phosphate buffer (0.01 M NaH2PO4·2 H2O with 2 mM EDTA, pH 6.0) and methanol (53:47; v/v) as the mobile phase. In order to develop a suitable sample preparation procedure, different methods have been tested (solid‐phase extraction, liquid‐liquid extraction, and protein precipitation). Protein precipitation using 0.1 M HClO4 and acetonitrile allowed the highest recoveries of the analyte to be reproducibly attained. The analytical methodology developed in this study was validated with respect to linearity (0.26–30.0 μg/mL), accuracy, precision, selectivity, recovery, and stability. A concentration of 0.26 μg/mL was determined as the LLOQ. The chromatographic method was applied to a preliminary plasma pharmacokinetic study. This study has provided the first information about the concentrations of SIH in plasma of a living subject. These results could have a significant impact on further progress in the development of this promising compound.
Purification of 3‐indolylacetic acid by solid phase extraction
Authors: Rolčík Jakub , Řečinská Jana , Barták Petr , Strnad Miroslav , Prinsen Els
Published: July 2005

This paper deals with the use of solid‐phase extraction (SPE) for the extraction and purification of 3‐indolylacetic acid (IAA), the main and most important representative of the plant growth regulators auxins. The procedure is based on the use of C18‐SPE columns in two steps. In the first one, raw extract in methanol:water (4:1) is applied on the column in order to remove neutral ballast. In the second step the eluate is diluted with water to a final methanol concentration of 20% (to decrease the elution strength of the solvent) and acidified with formic acid to a final concentration of 1% (to convert the IAA from the anionic to the neutral form). Neutral IAA is then retained on the second SPE column, eluted by (acidified) methanol, and subjected to final analysis. Scintillation counting of tritium labeled IAA standard was used for the investigation and optimization of the SPE procedure. Gas chromatography with mass spectrometric detection was suggested as a convenient method for routine determination of IAA after its methylation with diazomethane. Overall recovery of the procedure was estimated as 89–94% and a physiological level of IAA equal to 0.48 nmol/g (84 ng/g) fresh weight was found using an optimized SPE‐GC‐MS method.
Hydroquinone and Resorcinol‐Containing Copolyesters
Authors: Andrade Genara S. , Schiraldi David A. , Collard David M.
Published: July 2005

Summary: The successful incorporation of hydroquinone in thermal polyesterifications to prepare rigid linear copolyesters is hindered by the leaving group ability of phenols in nucleophilic acyl substitution reactions, the low nucleophilicity of phenols relative to aliphatic alcohols, and its volatility. To overcome these obstacles, with particular regard to improving the properties of poly(ethylene terephthalate), PET, we chose an approach whereby dyad‐based AB‐type mono(acetoxyphenyl) terephthalate monomers are transesterified into PET. In contrast to attempts to copolymerize terephthalic acid, ethylene glycol (EG) and hydroquinone, the transterification of small amounts (<10 mol‐%) of the preformed dyad in the absence of aliphatic diol, provides homogeneous random copolymers. Incorporation of larger amounts of aromatic diol gave only partly soluble materials. NMR analysis of the soluble fraction (in 20 vol.‐% TFA:CHCl3) indicated that the copolymers are substantially random. Transesterification of mono(4‐acetoxyphenyl) terephthalate (hydroquinone‐terephthalic acid, 1) and mono(3‐acetoxyphenyl) terephthalate (resorcinol‐terephthalic acid, 2) into PET allows us to further explore the effect of mesogen structure on the development of liquid crystalline copolyesters.

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Morphology and Dielectric Property of Homogenous BaTiO3/PVDF Nanocomposites Prepared via the Natural Adsorption Action of Nanosized BaTiO3
Authors: Dang Zhi‐Min , Wang Hai‐Yan , Zhang Yi‐He , Qi Jian‐Quan
Published: July 2005

Summary: The development of a novel technique for the preparation of homogeneous BaTiO3/polyvinylidene fluoride (BT/PVDF) nanocomposites without obvious agglomeration of BaTiO3 particles was reported in this communication. The morphology, structure, and frequency dependence of the dielectric properties of the nanocomposites were characterized. All results show that the dielectric properties of the nanocomposites in this study are desirable, and the process for preparing the nanocomposites has potential applications in the electronic industry.

TEM micrograph of dry BT/PVDF mixtures with nanosized BT particles.

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TEM micrograph of dry BT/PVDF mixtures with nanosized BT particles.
Fabrication of Au/Titania Composite Nanodot Arrays from Au‐Loaded Block Copolymer Micellar Films
Authors: Li Xue , Göring Petra , Pippel Eckhard , Steinhart Martin , Kim Dong Ha , Knoll Wolfgang
Published: July 2005

Summary: A simple route to an ordered array of metal/semiconductor oxide composite nanodots is presented. Micellar monolayer films of polystyrene‐block‐poly(2‐vinyl pyridine) (PS‐b‐P2VP) loaded with HAuCl4 in the P2VP nanodomains are used as templates. TiO2 is generated selectively within the polar P2VP domains of PS‐b‐P2VP/HAuCl4 films by chemical vapor deposition of TiCl4. Subsequent removal of the organic matrix by oxygen plasma or UV light leads to an array of Au/TiO2 composite nanoparticles on the substrate surface.

Schematic illustration of the process to fabricate an array of Au/titania composite nanodots.

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Schematic illustration of the process to fabricate an array of Au/titania composite nanodots.
Multi‐Objective Optimization of a Batch Copoly(ethylene‐polyoxyethylene terephthalate) Reactor Using Different Adaptations of Nondominated Sorting Genetic Algorithm
Authors: Kachhap Rakesh , Guria Chandan
Published: July 2005

Summary: A multi‐objective optimization is carried out for a copoly(ethylene‐polyoxyethylene terephthalate) (CEPT) batch reactor using different adaptations of the elitist nondominated sorting genetic algorithm (NSGA‐II). Several two objective function problems are formulated and solved. One objective is to minimize the total copolymerization time and other objective is to minimize the formation of total undesirable side products, namely, acid end group, vinyl ester end group, diethylene glycol ester end group of polyethylene terephthalate, and diethylene glycol. End‐point constraint is incorporated to obtain the specified number‐average degree of copolymerization. The operating temperature history of batch CEPT reactor is the only important decision variable for first optimization problem, whereas operating temperature history and molar ratio of feed to the reactor are taken as decision variables for the second optimization problem. Optimal Pareto frontiers are obtained for both the problems studied. In order to operate the polymerization reactor optimally, it is found that higher isothermal temperature history is needed for short copolymerization time, whereas lower nonisothermal temperature history is required for higher copolymerization time. The results of NSGA‐II technique are analyzed and compared with the jumping gene (JG) and adapted jumping gene (aJG) operator in NSGA‐II separately. It is found that NSGA‐II‐JG is superior to NSGA‐II and NSGA‐II‐aJG.

Optimization of a batch copoly(ethylene‐polyoxyethylene terephthalate) reactor.

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Optimization of a batch copoly(ethylene‐polyoxyethylene terephthalate) reactor.
Optimal Control of Batch MMA Polymerization with Specified Time, Monomer Conversion, and Average Polymer Molecular Weights
Authors: Sundaram Baranitharan S. , Upreti Simant R. , Lohi Ali
Published: July 2005

Summary: In this paper, the optimal control policies are determined for the free‐radical polymerization of methyl methacrylate (MMA) in a non‐isothermal batch reactor. The temperature of the fluid inside reactor‐jacket is used as the control function to realize four different optimal control objectives. Each objective is formulated to optimize a given variable simultaneously specifying another. The first two objectives target the maximization of monomer conversion in a specified operation time, and the minimization of operation time for a specified, final monomer conversion. The last two objectives target the maximization of monomer conversion for specified, final number‐ and weight‐average polymer molecular weights. The realization of these objectives is expected to be very useful for the batch production of polymers. To meet the specification of an optimization variable other than time, the differential model of batch process is expressed and utilized in the range of specified variable. Equations are provided for Jacobian evaluations to help in the accurate solution of process model. A genetic algorithms‐based optimal control method is applied to realize the four optimal control objectives. The results of this application show considerable improvements in the performance of batch MMA polymerization.

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Large time behaviour of solutions to Penrose–Fife phase change models
Authors: Feireisl Eduard , Schimperna Giulio
Published: July 2005

A non‐conserved phase transition model of Penrose–Fife type is considered where Dirichlet boundary conditions for the temperature are taken. A sketch of the proof of existence and uniqueness of the solution is given. Then, the large time behaviour of such a solution is studied. By using the Simon–Łojasiewicz inequality it is shown that the whole solution trajectory converges to a single stationary state. Due to the non‐coercive character of the energy functional, the main difficulty in the proof is to control the large values of the temperature. This is achieved by means of non‐standard a priori estimates. Copyright © 2005 John Wiley & Sons, Ltd.
Design and characterization of a multimeric DNA binding protein using Sac7d and GCN4 as templates
Authors: Wu Sz‐Wei , Ko Tzu‐Ping , Chou Chia‐Cheng , Wang Andrew H.‐J.
Published: July 2005

The protein Sac7d belongs to a class of small chromosomal proteins from the hyperthermophilic archaeon Sulfolobus acidocaldarius. Sac7d is extremely stable to heat, acid, and chemical agents. This protein is a monomer and it binds DNA without any particular sequence preference, while inducing a sharp kink in the DNA. By appending a leucine‐zipper‐like helical peptide derived from the yeast transcriptional activator GCN4 to the C‐terminal end of Sac7d, the modified monomers (denoted S7dLZ) are expected to interact with each other via hydrophobic force to form a parallel dimer. The recombinant S7dLZ was expressed in Escherichia coli and purified by heating and ion‐exchange chromatography. The formation of dimer was detected by gel‐filtration chromatography and chemical cross‐link. The results of surface plasmon resonance and circular dichroism experiments showed that the DNA‐binding capacity was retained. Furthermore, X‐ray diffraction analysis of single crystals of S7dLZ in complex with DNA decamer CCTATATAGG showed that the leucine‐zipper segments of S7dLZ were associated into an antiparallel four‐helix bundle. There are two DNA fragments bound to each S7dLZ tetramer in the crystal. This model works as a successful template that endows protein a new function without losing original properties. Proteins 2005. © 2005 Wiley‐Liss, Inc.
An Adaptive Sequential Procedure for Efficient Optimization of the Sheet Metal Spinning Process
Authors: Henkenjohann Nadine , Göbel Roland , Kleiner Matthias , Kunert Joachim
Published: July 2005

Due to technological advances in science, the complexity of processes under investigation increased continuously in recent years. For example, in mechanical engineering, there are often highly nonlinear input–output relationships combined with a large number of constraints. Sheet metal spinning is one example of such a production process. Many flexible and powerful methods to global optimization have been developed. In this paper, a sequential approach originally developed for computer experiments will be adopted and applied to optimize the spinning process based on physical experiments. This approach sequentially refines the model by adding new design points based on the expected improvement criterion. This criterion balances the need to observe at the predicted optimum with the need to investigate the design space in areas of high uncertainty. However to guarantee an efficient optimization of the spinning process, this approach has to be embedded in a more substantial procedure. One reason for this is the liability of workpiece failure for most of the operable design space. Since the shape of the failure region is unknown, many missing observations have to be expected when exploring the design space. The other reason is the need to incorporate available process knowledge of sheet metal spinning to improve the efficiency in optimization. The main problem in implementing this information is a changing process behavior for different geometries and materials used. Hence, if a component with a new geometry has to be optimized, it is difficult to include available process knowledge. In this paper, an adaptive sequential optimization procedure (ASOP) is presented to cope with these problems in order to guarantee an efficient optimization of such complex processes. The approach is exemplified by optimizing the spinning process for a fixed geometry. Copyright © 2005 John Wiley & Sons, Ltd.
Using Evolutionary Operation to Improve Yield in Biotechnological Processes
Authors: Kvist Trine , Thyregod Peter
Published: July 2005

In the biotechnological industry, production is often characterized by relatively few larger batches. In the design stages of a new process, the use of statistical methods for experimentation can provide invaluable information about the process. However, it is frequently found that optimum conditions in the laboratory or pilot plant give lower yields when transferred to full‐scale production. This fact is due to scale‐up effects and to the large inherent variations when dealing with biological material and processes such as fermentation. In full‐scale production there is not the same freedom to experimentation as at the laboratory scale. Simple one factor at a time trials are predominant when attempting to improve the yield at the production scale. In this way it is possible to control the outcome such that it still meets the requirements. However, this is a very inefficient way to perform experiments. The requirements for an alternative experimental procedure is that it should be robust to non‐controllable variations, it should contain automatic safeguards to ensure that unsatisfactory material is not manufactured and it should be possible to make decisions during the trial. Furthermore, it is important that the planning stage is short and the interpretation straightforward. The method of evolutionary operation (EVOP) suggested by George Box fulfilled these requirements. We present the implementation of EVOP in a major Danish biotechnological company. An example is presented where the method was used in the fermentation process of an industrial enzyme. In the particular example, process yield was improved by 45%. Copyright © 2005 John Wiley & Sons, Ltd.
Process Improvement in the Microelectronic Industry by State Space Modelling
Authors: Triantafyllopoulos K. , Godolphin J. D. , Godolphin E. J.
Published: July 2005

The exponentially weighted moving average (EWMA) model can be applied to a process controlling the thickness of nitride layers in the manufacture of microelectronic devices, involving the standard use of the notions of EWMA control chart, EWMA full adjustment and EWMA deadband adjustment charts for process monitoring and process improvement. We suggest that a dynamic step forward to process improvement is gained by considering basic state space models, which are known as local‐level models. The EWMA predictor is a limiting form of forecast for the local‐level model, so we propose replacing the EWMA by a local‐level model and thus develop feedback adjustment schemes. Under Gaussian assumptions, the entire forecast distribution is obtained routinely. A detailed development of the proposed state space adjustment scheme is given to the nitride layers process and a number of conclusions and recommendations are made. The proposed scheme is found to perform better than the EWMA if there is evidence of a shift in the level of the output process. Copyright © 2005 John Wiley & Sons, Ltd.
Statistical Modelling of MOS Transistor Mismatch for High‐voltage CMOS Processes
Authors: Posch Werner , Enichlmair Hubert , Schirgi Eduard , Rappitsch Gerhard
Published: July 2005

The random mismatch of semiconductor devices caused by local variations of the production process strongly influences critical performance parameters of analog circuits. In order to estimate the influence of the device mismatch on the circuit yield during the design phase, statistical mismatch models for the individual components must be provided for circuit simulation. Based on extensive statistical measurements of matched pairs using special test structures, an algorithm is presented to extract device mismatch parameters for high‐voltage transistors. Due to the special construction of high‐voltage transistors the mismatch parameters must be determined in two steps taking into account the effect of the drift region at high gate voltages. Therefore, the device mismatch for the threshold voltage, the gain factor and the mobility reduction are extracted from a sensitivity model in saturation, whereas the extraction of the drift‐resistance mismatch uses a modified MOS transistor model in the ohmic region. Based on the mismatch parameters for several device sizes a proper geometric model is extracted allowing the mismatch parameters to be scaled with the device dimensions. The mismatch parameters are implemented as part of circuit simulation model libraries to be used for Monte Carlo simulation. Production control parameters enable the monitoring of device mismatch for high‐voltage CMOS transistors. Copyright © 2005 John Wiley & Sons, Ltd.
Analysis of Split‐plot Designs with Mirror Image Pairs as Sub‐plots
Authors: Tyssedal John , Kulahci Murat
Published: July 2005

In this article we present a procedure to analyze split‐plot experiments with mirror image pairs as sub‐plots when third‐ and higher‐order interactions can be assumed negligible. Although performing a design in a split‐plot manner induces correlation among observations, we show that with such designs the essential search for potentially active factors can be done in two steps using ordinary least squares. The suggested procedure is tested out on a real example and on two simulated screening examples; one with a split‐plot design based on a geometric design and one with a split‐plot design based on a non‐geometric Plackett and Burman design. The examples also illustrate the advantage of using non‐geometric designs where the effects are partially aliased instead of being fully aliased as in highly fractionated fractional factorials. Copyright © 2005 John Wiley & Sons, Ltd.
Ab initio calculation of the interaction energy in the P2 binding pocket of HIV‐1 protease
Authors: Nivesanond Kanda , Peeters Anik , Lamoen Dirk , Van Alsenoy Christian
Published: July 2005

Interactions at the P2 binding pocket of human immunodeficiency virus type 1 (HIV‐1) protease have been studied using calculated interaction energies for model systems that mimic this binding pocket. Models were built for the P2 pocket of HIV‐1 protease in complex with TMC114, nelfinavir, and amprenavir. A two‐step procedure was applied. In the first step, the size of the model system was confined to ∼40 atoms, and the interaction energy was calculated at different computational levels. In the second step, the size of the system was increased to 138 atoms, and the calculations were only performed at the HF/6‐31G** level. The interaction energy of the HIV‐1 protease/TMC114 complex was found to be more favorable than the interaction energies of the other complexes because of the additional hydrogen bond interaction this inhibitor is able to make with the HIV‐1 protease backbone. The results of the calculations are supported by stockholder charges and electrostatic potential maps. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
The Sensitizers Nickel Sulfate and 2,4-dinitrofluorobenzene Increase CD40 and IL-12 Receptor Expression in a Fetal Skin Dendritic Cell Line
Authors: Vital Ana Luísa , Gonçalo Margarida , Cruz Maria Teresa , Figueiredo Américo , Duarte Carlos B. , Lopes Maria Celeste
Published: July 2005

Dendritic cells (DCs) are antigen-presenting cells (APCs) capable of capturing haptens and to process and present them to T lymphocytes. In order to sensitize T cells for contact hypersensitivity (CHS), skin DCs suffer a maturation process with modifications on their surface molecules. The aim of this work was to evaluate changes induced by two contact sensitizers, 2,4-dinitrofluorobenzene (DNFB) and nickel sulfate (NiSO4), and a non-sensitizer 2,4-dichloronitrobenzene (DCNB), on the protein levels of two activation markers, CD40 and IL-12 receptor (IL-12R), in a mouse skin dendritic cell line (FSDC). The expression of CD40 and IL-12R proteins was evaluated by western blot assay and direct immunofluorescence microscopy. The results showed that CD40 and IL-12R expression increased significantly after cell exposure to NiSO4 and DNFB, although DNFB exhibited a stronger activity. There was no effect with DCNB. The epidermal cytokine granulocyte–macrophage colony-stimulating factor (GM-CSF), also used in the experiments, slightly increased the expression of both CD40 and IL-12R and when tested together with the sensitizers the effect was partially additive. The results suggest that the sensitizers DNFB and NiSO4 are directly involved on the changes of the surface markers CD40 and IL-12R in skin DCs, during the sensitization phase of CHS, and this effect may be enhanced by GM-CSF. In contrast, no effect was observed with DCNB.
Height Changes Associated with Pigment Aggregation inXenopus laevisMelanophores
Authors: Immerstrand Charlotte , M. Nilsson Harriet , Lindroth Margaretha , Sundqvist Tommy , Magnusson Karl-Eric , Holmgren Peterson Kajsa
Published: July 2005

Melanophores are pigment cells found in the skin of lower vertebrates. The brownish-black pigment melanin is stored in organelles called melanosomes. In response to different stimuli, the cells can redistribute the melanosomes, and thereby change colour. During melanosome aggregation, a height increase has been observed in fish and frog melanophores across the cell centre. The mechanism by which the cell increases its height is unknown. Changes in cell shape can alter the electrical properties of the cell, and thereby be detected in impedance measurements. We have in earlier studies of Xenopus laevis melanophores shown that pigment aggregation can be revealed as impedance changes, and therefore we were interested in investigating the height changes associated with pigment aggregation further. Accordingly, we quantified the changes in cell height by performing vertical sectioning with confocal microscopy. In analogy with theories explaining the leading edge of migrating cells, we investigated the possibility that the elevation of plasma membrane is caused by local swelling due to influx of water through HgC12-sensitive aquaporins. We also measured the height of the microtubule structures to assess whether they are involved in the height increase. Our results show that pigment aggregation in X. laevis melanophores resulted in a significant height increase, which was substantially larger when aggregation was induced by latrunculin than with melatonin. Moreover, the elevation of the plasma membrane did not correlate with influx of water through aquaporins or formation of new microtubules, Rather, the accumulation of granules seemed to drive the change in cell height.
Corner defects in almost planar interface propagation
Authors: Haragus Mariana , Scheel Arnd
Published: July 2005

We study existence and stability of interfaces in reaction–diffusion systems which are asymptotically planar. The problem of existence of corners is reduced to an ordinary differential equation that can be viewed as the travelling-wave equation to a viscous conservation law or variants of the Kuramoto–Sivashinsky equation. The corner typically, but not always, points in the direction opposite to the direction of propagation. For the existence and stability problem, we rely on a spatial dynamics formulation with an appropriate equivariant parameterization for relative equilibria.

Nous étudions l'existence et la stabilité des interfaces asymptotiquement planes dans des systèmes de réaction–diffusion. Le problème de l'existence des défauts est réduit à l'étude d'une équation différentielle ordinaire qui est, selon le cas, approchée par l'équation stationnaire d'une loi de conservation scalaire ou d'une variante de l'équation de Kuramoto–Sivashinsky. Typiquement, les défauts pointent dans la direction opposée à la direction de propagation. Pour l'analyse des problèmes d'existence et de stabilité, nous utilisons une formulation de type dynamique spatiale combinée avec une paramétrisation adéquate d'équilibres relatifs.
Effect of new antioxidant cysteinyl‐flavanol conjugates on skin cancer cells
Authors: Lozano Carles , Torres Josep Lluís , Julià Lluís , Jimenez Aurora , Centelles Josep Joan , Cascante Marta
Published: July 2005

Novel catechin derivatives obtained from grape procyanidins and l‐cysteine scavenge free radicals by hydrogen atom donation, rather than electron transfer, and reduce cell viability in A375 and M21 melanoma cells. In particular, 4β‐(S‐cysteinyl)epicatechin 3‐O‐gallate has a free radical scavenging capacity as strong as that of tea (−)‐epigallocatechin gallate and causes a significant S‐phase cell‐cycle arrest in both cell lines at doses higher than 100 μM. The other cysteinyl compounds do not affect normal cell cycle distribution. The gallate derivative also induces apoptosis in melanoma cells more strongly than the other derivatives and the parent (−)‐epicatechin do. The gallate compound seems to trigger nuclear condensation and fragmentation, which is confirmed by DNA laddering. Interestingly, they do not induce apoptosis in keratinocytes (HaCaT).
The effects of the interactions between amino acids on pyruvate kinase activity from the brain cortex of young rats
Authors: Feksa Luciane Rosa , Cornelio Andrea , Dutra‐Filho Carlos Severo , de Souza Wyse Angela Terezinha , Wajner Moacir , Wannmacher Clovis Milton Duval
Published: July 2005

Considering that pyruvate kinase activity, a crucial enzyme for glucose metabolism and energy liberation in brain, may be regulated by some amino acids, it is possible that diminution of this enzyme activity may contribute to the brain damage caused by amino acids accumulated in metabolic diseases, such as phenylalanine, tryptophan and cystine. Therefore, the present study was undertaken to investigate the effect of these amino acids on pyruvate kinase activity in the brain cortex of rats. We also investigated the effect of serine and alanine on pyruvate kinase activity in the same tissue. The results suggested that phenylalanine, tryptophan, cystine, alanine, and serine act at the same site on the enzyme, phenylalanine, tryptophan, and cystine causing inhibition, and alanine and serine preventing this effect. Cystine also inhibited the enzyme activity through a different mechanism, possibly acting on the enzyme thiol groups. Considering that this enzyme is a target for amino acids accumulated in some metabolic diseases of amino acid metabolism, it is possible that its inhibition may contribute to the brain damage found in these diseases.
An exploratory study of ‘close’ supplier–manufacturer relationships
Authors: Goffin Keith , Lemke Fred , Szwejczewski Marek
Published: July 2005

Close relationships with selected suppliers can enable manufacturers to reduce costs, improve quality and enhance new product development. Although the advantages of close co‐operation are widely acknowledged in the literature, the specific attributes of such relationships are not well understood. To address this gap, 39 managers responsible for purchasing were interviewed using a technique from psychology, which is particularly effective at uncovering the characteristics of relationships. This approach is innovative in the context of supplier management research and gave insights into how manufacturers expect more from their suppliers than just reliable deliveries of high‐quality, well‐priced parts and components. The results of the empirical research enhance our knowledge of the attributes of manufacturer–supplier relationships and also indicate how manufacturers can establish close relationships with selected suppliers. Overall, the study has established the viability of a new approach for understanding the complex topic of manufacturer–supplier partnerships.
Management of the Vertebral Artery at the Craniocervical Junction
Authors: Çokkeser YasLar , Naguib Maged B. , Kizilay Ahmet
Published: July 2005

OBJECTIVES:

To study the surgical anatomy of the vertebral artery at the craniocervical junction and its related structures defining reliable landmarks for its safe exposure.

DESIGN:

Ten sides of 5 fresh cadavers were dissected using the lateral approach to the craniocervical junction.

RESULTS:

Experience gained in studying the anatomic details of the vertebral artery at the craniocervical junction in cadavers from its exit at the transverse foramen of the second cervical vertebra to the vertebrobasilar junction provided the initial background for us to use the lateral approaches to the skull base to safely manage 4 cases with pathology reaching the close vicinity of vertebral artery at the craniocervical junction.

CONCLUSION:

Thorough knowledge of the anatomy of the vertebral artery is mandatory before attempting surgery at the craniocervical junction. There are reliable landmarks that, when followed, could facilitate safe exposure and identification of the artery.
Radiofrequency Excision versus Monopolar Electrosurgical Excision for Tonsillectomy
Authors: Littlefield Philip D. , Hall Daniel J. , Holtel Michael R.
Published: July 2005

OBJECTIVE:

We previously compared radiofrequency (Evac) tonsillotomy with monopolar electrosurgical (Bovie) tonsillectomy and showed significantly less pain with the Evac. Tonsillotomy leaves a cuff of tonsil behind, the significance of which is unknown. We hypothesize that Evac tonsillectomy also is less painful than Bovie tonsillectomy.

STUDY DESIGN AND SETTING:

We compared Evac (ENTec Evac 70; ArthroCare, Sunnyvale, CA) and Bovie tonsillectomy in a prospective, blinded fashion. Each participant had 1 tonsil removed by each device. We recorded, by side, the surgical time, blood loss, operative difficulty, pain (postoperative days 1, 3, 5, 7, 10, and 14), and the side that each patient preferred.

RESULTS:

Data were analyzed for 17 patients. They reported significantly less pain with the Evac (P < 0.036, F = 5.87). The Evac was preferred by 12 of 14 patients.

CONCLUSION:

Evac tonsillectomy is significantly less painful than Bovie tonsillectomy. Patients blinded to treatment preferred the Evac technique.

SIGNIFICANCE:

The Evac device decreases postoperative pain.
Primary versus Secondary Tracheoesophageal Puncture for Speech Rehabilitation in Total Laryngectomy: Long‐Term Results with Indwelling Voice Prosthesis
Authors: Chone Carlos T. , Gripp Flávio M. , Spina Ana L. , Crespo Agricio N.
Published: July 2005

OBJECTIVE:

To evaluate the long‐term use of indwelling Blom‐Singer voice prosthesis (VP) for vocal rehabilitation of patients submitted to total laryngectomy (TL). The influence of the timing (primary or secondary) of tracheoesophageal puncture (TEP), use of radiotherapy (xRT), patient age, and length of follow‐up were studied to evaluate the success rate of VP use.

STUDY DESIGN AND SETTING:

Prospective clinical study in a tertiary referral center. Seventy‐one patients were submitted to TL and rehabilitated with indwelling VP. All patients were evaluated for vocal functional issues by an otolaryngologist and a speech pathologist at 1 month, then at every 3 months up to 1 year, and then at every 6 months after 1 year of follow‐up. The relative data on time of placement of VP, time of VP use, xRT, age, length of follow‐up, and life span of each VP were recorded during the follow‐up.

RESULTS:

Eighty‐seven percent of the patients underwent primary and 13%, secondary TEP. The follow‐up varied from 12 to 87 months, with an average of 38 months for primary and 51 months for secondary TEP. Fifty‐nine percent of the patients were submitted to xRT. The general rate of success was 94%, with 97% for primary and 78% (P = 0.07) for secondary TEP; after 2 years, the success rate was 96% for primary and 75% for secondary (P = 0.07) TEP. The use of xRT and patient age had no influence on the success of VP use for primary and secondary TEP, independently of the length of follow‐up.

CONCLUSIONS:

The success rate of voice rehabilitation with VP was 94%. In primary TEP, the success rate was 97%, whereas in secondary TEP it was 78%; 2 years later, it was 96% and 75%, respectively. A tendency for a higher success rate in voice rehabilitation after TL was observed in primary TEP. The use of xRT and age of patient had no influence on the success rate.
The Efficacy of Hypertonic Saline Nasal Irrigation for Chronic Sinonasal Symptoms
Authors: Rabago David , Pasic Thomas , Zgierska Aleksandra , Mundt Marlon , Barrett Bruce , Maberry Rob
Published: July 2005

OBJECTIVE:

To assess quality of life (QOL) in patients with sinonasal symptoms in response to hypertonic saline nasal irrigation (HSNI), and to assess HSNI use patterns.

STUDY DESIGN AND SETTING:

The study was an uncontrolled 12‐month follow‐up to a randomized controlled trial (RCT) and used HSNI in a community setting. We included 54 participants with recurrent or chronic sinonasal symptoms. Forty participants had been in the intervention group of a previous study; 14 had been control participants. Primary outcome measures were the Rhinosinusitis Disability Index (RSDI), a sinus‐symptom severity assessment (SIA), and the Sino‐Nasal Outcomes Test (SNOT‐20). Secondary outcome measures were frequency and pattern of HSNI use, side effects and satisfaction.

RESULTS:

Among participants using HSNI in the prior RCT, RSDI scores continued to improve, from 73.2 ± 2.6 points to 80.6 ± 2.4 points (P < 0.001). SIA and SNOT‐20 scores remained stable. Former control participants reported QOL improvement similar to that of HSNI users in the prior RCT. RSDI scores improved from 62.0 ± 3.9 points to 79.7 ± 3.7 points (P < 0.05), SNOT‐20 scores improved from 43.5 ± 5.7 points to 28.4 ± 4.8 points, and SIA scores improved from 4.2 ± 0.3 points to 2.6 ± 0.3 points (P < 0.01). Mean HSNI use for all participants was 2.4 irrigations per week; 33% of participants used HSNI regularly, 55% when symptomatic. Side effects were minor; satisfaction was high.

CONCLUSIONS:

Participants with chronic sinonasal symptoms reported improved QOL and frequent, satisfying use of HSNI.

SIGNIFICANCE:

HSNI is an effective adjunctive treatment of chronic sinonasal symptoms.
The Role of the Osteocutaneous Radial Forearm Free Flap in the Treatment of Mandibular Osteoradionecrosis
Authors: Militsakh Oleg N. , Wallace Derrick I. , Kriet J. David , Tsue Terance T. , Girod Douglas A.
Published: July 2005

OBJECTIVE:

To evaluate the role of the osteocutaneous radial forearm free flap (OCRFFF) in the treatment of mandibular osteoradionecrosis (ORN).

STUDY DESIGN AND SETTING:

Retrospective case review of patients who underwent OCRFFF oromandibular reconstruction after resection of nonviable tissue at an academic tertiary care center because of ORN. Patients with reconstructions other than OCRFFF were excluded from this study.

RESULTS:

Nine patients underwent a composite oromandibular resection for ORN with a reconstruction using an OCRFFF between April 1998 and February 2003. All patients had failed previous less aggressive surgical and medical management of the ORN. Mean follow‐up was 36 months (range, 14‐67 months). There were no flap failures or significant immediate postoperative or long‐term complications observed. All patients had successful restoration of mandibular integrity and continuity, with 100% success rate of stabilization of ORN. All patients were able to tolerate PO diet, with only one third having to supplement their diet with gastrostomy feedings, compared with 89% gastrostomy dependence preoperatively.

CONCLUSIONS:

Primary or adjuvant radiotherapy for head and neck malignancies can result in ORN of the mandible. This difficult problem often requires surgical intervention. In our experience, the OCRFFF can be successfully used for oromandibular reconstruction, even in the setting of the heavily radiated tissue with excellent postoperative outcomes.

SIGNIFICANCE:

This is the first study that demonstrates the efficacy of the OCRFFF as a treatment of mandibular ORN.
Complications of Acute Sinusitis in Children
Authors: Oxford Lance E. , McClay John
Published: July 2005

OBJECTIVE:

To review the demographic, microbiologic, and outcome data for children with complications of acute sinusitis.

STUDY DESIGN AND SETTING:

Retrospective review of children admitted with complications of acute sinusitis from January 1995 to July 2002 to a tertiary care children's hospital.

RESULTS:

One hundred four patients were reviewed with the following complications: orbital cellullitis (51), orbital abscesses (44), epidural empyemas (7), subdural empyemas (6), intracerebral abscesses (2), meningitis (2), cavernous sinus thrombosis (1), and Pott's puffy tumors (3). Sixty‐six percent were males (P < 0.001), and 64.4% presented from November to March (P < 0.001). Patients with isolated orbital complications were younger than patients with intracranial complications (mean, 6.5 versus 12.3 years), had a shorter stay (mean, 4.2 versus 16.6 days), and had shorter duration of symptoms (mean, 5.4 versus 14.3 days; all P < 0.0001). Complete resolution was documented for 54/55 patients with restricted ocular motility, 7/8 with visual loss, 3/3 patients with a nonreactive pupil, 7/7 with neurological deficits, and 2/4 with seizures. The most common organism isolated was Streptococcus milleri (11/36 patients with surgical cultures). No mortalities occurred, and persistent morbidity occurred in 4 patients (3.8%).

CONCLUSIONS:

Despite significant deficits on presentation, permanent morbidity was low. Streptococcus milleri is a common pathogen with complications of sinusitis in children.
Differentiation between Cerebrospinal Fluid and Serum with Electronic Nose
Authors: Aronzon Anna , Hanson C. William , Thaler Erica R.
Published: July 2005

OBJECTIVE:

The study investigates the ability of the electronic nose to differentiate between cerebrospinal fluid (CSF) and serum and to identify an unknown specimen as CSF or serum.

STUDY DESIGN AND SETTING:

CSF and serum specimens were heated and tested with an organic semiconductor‐based Cyranose 320 electronic nose (Cyrons Sciences, Pasadena, CA). Data from the 32‐element sensor array were subjected to principal component analysis to depict differences in odorant patterns.

RESULTS:

The electronic nose was able to distinguish between CSF and serum isolates with Mahalanobis distance >5. Furthermore, the electronic nose was able to place unknown specimens in the appropriate class of CSF or serum.

CONCLUSIONS:

The electronic nose is a novel method that may allow rapid, low cost, and reliable distinction between CSF and serum in a clinical setting.

SIGNIFICANCE:

Because the results are available almost immediately, the electronic nose is a powerful tool that in the future may allow for rapid diagnosis of CSF leaks in the office setting.
Rhabdomyosarcomas of the Nose and Paranasal Sinuses: Treatment Results in 15 Cases
Authors: Wurm Jochen , Constantinidis Jannis , Grabenbauer Gerhard G. , Iro Heinrich
Published: July 2005

OBJECTIVE:

Primary rhabdomyosarcomas (RMS) of the nose and the paranasal sinuses occur very rarely. Treatment of these tumors usually is conducted according to standardized therapy protocols like the German Cooperative Soft Tissue Sarcoma Study (CWS) or the Intergroup Rhabdomyosarcoma Study (IRS). The role of surgery still remains controversial.

STUDY DESIGN AND SETTING:

A retrospective analysis of 15 patients with an RMS of the nose or paranasal sinuses treated between 1979 and 2000 is presented. Patients' age ranged from 2 to 60 years, with an average of 22 years. Histologic subtypes encompassed 9 embryonal (e) and 6 alveolar (a) RMS. Resection of the tumor with subsequent radiochemotherapy (RCT) was performed in 6 cases, and primary RCT, in 9 cases. The average duration of follow‐up was 4 years and 10 months.

RESULTS:

Overall 5‐year survival was 40%. In the patient group subjected to tumor resection with subsequent RCT, 5‐year survival was 66%, compared with 33% after exclusive primary RCT. With respect to histologic subtype, 5‐year survival was 55% for eRMS, as compared with 33% for aRMS. Moreover, infiltration of the skull base and the presence of a residual tumor after primary therapy constituted factors associated with an unfavorable clinical course.

CONCLUSIONS:

Surgical removal of tumor with subsequent radiochemotherapy can be recommended if a complete resection and functionally and cosmetically satisfactory results appear possible. Patients with eRMS showed an overall more favorable clinical course than patients with aRMS.
Effect of Treatment by Laser‐Assisted Uvulopalatoplasty on Cardiopulmonary Exercise Test in Obstructive Sleep Apnea Syndrome
Authors: Lin Ching‐Chi , Chang Ke‐Chang , Lee Kuo‐Sheng , Wu Kun‐Ming , Chou Chon‐Shin , Lin Ching‐Kai
Published: July 2005

OBJECTIVES:

To evaluate the effects of successful laser‐assisted uvulopalatoplasty (LAUP) on cardiopulmonary exercise testing (CPET) in patients with obstructive sleep apnea syndrome (OSAS).

STUDY DESIGN AND SETTING:

Twenty‐five subjects with moderately severe or severe OSAS who desired LAUP were enrolled. All patients had an overnight sleep study and CPET before and 3 months after LAUP. Patients were divided into 2 groups based on the success (group I) or failure (group II) of LAUP to improve their sleep apnea.

RESULTS:

Successful LAUP in group I was followed by improvement in right ventricular ejection fraction, maximal work rate (WRmax), VO2max/kg, anaerobic threshold, oxygen pulse, and a lower breathing reserve. CPET results were unchanged after LAUP in group II subjects.

CONCLUSION:

Patients with OSAS before LAUP had abnormal CPET as reflected by low VO2peak/kg, WRmax, anaerobic threshold, and oxygen pulse. All of these variables improved after LAUP that successfully ameliorated OSAS.