bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclodextrin‐modified micellar electrokinetic chromatography for the analysis of Esterom®, a topical product consisting of hydrolyzed benzoylecgonine in propylene glycol
Authors: Razak Jennifer L. , Doyen Heidi J. , Lunte Craig E. 
Published: May 2003

AbstractEsterom®, a new drug currently in human clinical trials, is a mixture of compounds in a propylene glycol vehicle. It is being evaluated as a topical treatment to aid in the relief of muscle pain and to increase range of motion. Benzoylecgonine is the major component of Esterom and there are at least nine other minor constituents, including four hydroxypropyl esters that have multiple diasteriomers. The aim of the study was to develop a capillary electrophoresis method for the simultaneous separation of the main components in Esterom, including the multiple proposed diastereomers of the esters. Due to the complex sample composition, the use of micelles and cyclodextrins as buffer modifiers was evaluated. A cyclodextrin‐modified micellar electrokinetic chromatography method was able to determine 7 of the 8 UV‐active Esterom components, with baseline separation of 7 of the 10 diastereomers of the hydroxypropyl esters.
Size‐exclusion capillary electrochromatographic separation of polysaccharides using polymeric stationary phases
Authors: Mistry Kavita , Krull Ira , Grinberg Nelu 
Published: May 2003

AbstractWe report the successful size‐based separations of large, neutral polysaccharides using capillary electrochromatography (CEC). As the polysaccharides possessed little chromophore for photometric detection, two separate approaches were taken. In the first approach, indirect detection was combined with size‐exclusion chromatography using a sulfonated polystyrene/divinylbenzene stationary phase. The separations were performed using a 300 Å pore size stationary phase under aqueous conditions. Non‐size based interactions were minimal using this material, resulting in an effective calibration range of molecular masses 180 to 112 000 g·mol−1 for pullulans. In the second approach, the polysaccharides were derivatized with phenylisocyanate and were subsequently separated on columns made using a combination of high capacity ion‐exchanger and a neutral polystyrene/divinylbenzene material of various pore sizes. The sulfonated ion‐exchange phase provided the electroosmotic flow, while the mixed pore size material provided the extended calibration range. The linear range for this primarily nonaqueous system using tetrahydrofuran was determined to be from molecular masses 738 to 404 000 g·mol−1 of the original, untagged pullulan. This approach overcame the limited solubility issue associated with analysis of some polysaccharides. Analysis of pullulan and amylose samples by CEC correlated well with results obtained by conventional high‐performance liquid chromatography (HPLC). The size‐exclusion electrochromatographic separations provide an alternative mode for determining the relative molecular weights of polysaccharides with reduced sample and solvent consumption, as well as analysis times.
An optimized method for the isolation and identification of membrane proteins
Authors: Lehner Ines , Niehof Monika , Borlak Jürgen 
Published: May 2003

AbstractThe purpose of this study was to develop a protocol suitable for membrane protein extraction from limited starting material and to identify appropriate conditions for two‐dimensional (2‐D) gel electrophoresis. We used A549 cells, a human alveolar type II cell line, and evaluated three protein extraction methods based on different separation principles, namely protein solubility, detergent‐based and density‐based organelle separation. Detergent‐based extraction achieved the highest yield with 14.64% ± 2.35 membrane proteins but sequential extraction with 7.35% ± 0.78 yield and centrifugal extraction with 4.1% ± 0.54 yield produced the purest fractionation of membrane proteins. Only the sequential and the detergent‐based extraction proved suitable for small volumes of starting material. We identified annexin I + II, electron transfer flavoprotein β‐chain, H+‐transporting ATP synthase, mitofilin and protein disulfide isomerase A3 as membrane and cytokeratin 8 + 18, actin and others as soluble proteins using matrix assisted laser desorption/ionization‐time of flight (MALDI‐TOF) analysis and started to map the A549 cell proteome. Our data suggest that membrane proteins can be extracted efficiently from small samples using a simple sequential protein extraction method. They can be separated and identified successfully using optimized conditions in 2‐D gel electrophoresis. The presented methods will be useful for further investigations of membrane proteins of alveolar and bronchial carcinomas.
Improved resolution with microchip‐based enhanced field inversion electrophoresis
Authors: Backhouse Christopher J. , Gajdal Ania , Pilarski Linda M. , Crabtree H. John 
Published: May 2003

AbstractWe present an improvement of the field inversion electrophoresis (FIE) method in which the passage of sample such as DNA back and forth within a short length of a microchannel can provide a similar resolution to that of a significantly longer microchannel. In constant field FIE the application of an alternating potential (e.g., +/− V) over short periods of time (e.g., several Hz) can provide enhanced separations of DNA fragments. In contrast, the present method consists of a series of separations, each of much longer duration, under high and low fields in such a way that the resolution is enhanced. This method is readily modeled and allows improved resolution to be obtained from extremely short microchannels (e.g., 8 mm) while requiring relatively low applied voltages (e.g., less than 600 V). An additional advantage is that this method can allow for the same equipment to be used in a rapid, low‐resolution mode or in a slower, high‐resolution mode through what might be referred to as an automated “zoom” capability. We believe that this method may facilitate the integration of microfluidic devices and microelectronic devices by allowing these devices to be of a similar small scale (< 1 cm).
A versatile electrophoresis system for the analysis of high‐ and low‐molecular‐weight proteins
Authors: Tastet Christophe , Lescuyer Pierre , Diemer Hélène , Luche Sylvie , van Dorsselaer Alain , Rabilloud Thierry 
Published: May 2003

AbstractA new, versatile, multiphasic buffer system for high‐resolution sodium dodecyl sulfate‐polyacrylamide gel electrophoresis of proteins in the relative molecular weight range of 300 000–3000 Da is described. The system, based on the theory of multiphasic zone electrophoresis, allows complete stacking and destacking of proteins in the above Mr range. The buffer system uses taurine and chloride as trailing and leading ion, respectively, and Tris, at a pH close to its pKa, as the buffering counterion. Coupled with limited variation in the acrylamide concentration, this electrophoresis system allows to tailor the resolution in the 6–200 kDa Mr range, with minimal difficulties in the post electrophoretic identification processes.
A rat brain protein expression map including cytosolic and enriched mitochondrial and microsomal fractions
Authors: Krapfenbauer Kurt , Fountoulakis Michael , Lubec Gert 
Published: May 2003

AbstractProteomics is a powerful tool to screen brain protein expression but the methodology is hampered by low abundance of proteins or compartmentalization or overload of high‐abundance proteins. It was therefore the aim of the study to determine the expression of brain proteins by using enriched cellular subfractions and pre‐electrophoretic chromatographical separation of brain homogenates. We used two‐dimensional electrophoresis with subsequent matrix‐assisted laser desorption/ionization (MALDI) detection and characterization of brain proteins. Subfractionation into cytosolic, mitochondrial and microsomal compartments was performed by ultracentrifugation. Pre‐electrophoretic fractionation of the cytosolic fractions was carried out by ion exchange column chromatography. We detected and identified a large series of 437 proteins in rat brain and have shown proteins specific for the individual subcellular compartments. These proteins included housekeeping, signaling, cytoskeletal, intermediary metabolism, antioxidant proteins on the one and neuron and synaptosomal specific proteins on the other hand. Using fractionations of brain homogenates we were able to improve the power of the method on forming the basis for brain protein expressional studies and providing a reference map as a powerful tool for the neuroscientist.
Electrophoretic separation and confocal laser‐induced fluorescence detection at ultralow concentrations in constricted fused‐silica capillaries
Authors: Lundqvist Anders , Chiu Daniel T. , Orwar Owe 
Published: May 2003

AbstractLaser‐induced fluorescence detection of labeled amino acids in a flowing stream at femtomolar (10−15M) concentrations was achieved by using a fused‐silica capillary flow‐cell comprising a constricted thin‐walled detection region with inner diameters (IDs) ranging from 2 to 8 μm. The diameter of the constricted region was made to match a diffraction‐limited focus of a uniphase transverse electromagnetic mode (TEM00) laser beam. Optimization of capillary dimensions and geometries (i.e., curvature, wall thickness, and outer‐inner diameter ratio were performed in order to minimize cylindrical lensing of the focused laser beam. The fluorescence was collected in a confocal optical setup using a 1.3 numerical aperture (NA), 100× oil‐immersion objective and a single‐photon‐counting avalanche diode (SPAD). Under conditions of fluid flow, the constriction in the capillary forces all analytes to traverse across the laser probe volume, resulting in a high sampling efficiency. Fluorescein isothiocyanate‐labeled glutamate (FITC‐Glu) was electrophoretically separated and detected in capillaries having an ID of 2 μm at the constricted region with detection limits of 250 fM (signal‐to‐noise ratio (S/N) = 3) in the injected solution.
Method for clone checking
Authors: Nourizad Nader , Gharizadeh Baback , Nyrén Pål 
Published: May 2003

AbstractA new method for simple and fast clone checking is described. We combined the Pyrosequencing™ technology with a preprogrammed nucleotide dispensation strategy for fast analysis of DNA constructs. To test this method, the N‐terminus region of plasmids constructed for the production of recombinant apyrase was analyzed. Of the ten plasmids tested, seven constructs were correct, two constructs showed one base deletion, and one construct showed deletion of a 195 bp fragment. The preprogrammed nucleotide dispensation strategy allowed the identification of the sequence downstream of the deletions. Thus, this method determines both the location and nature of possible artifacts.
On the convergence of the finite integration technique for the anisotropic boundary value problem of magnetic tomography
Authors: Potthast Roland , Kühn Lars 
Published: May 2003

AbstractThe reconstruction of a current distribution from measurements of the magnetic field is an important problem of current research in inverse problems. Here, we study an appropriate solution to the forward problem, i.e. the calculation of a current distribution given some resistance or conductivity distribution, respectively, and prescribed boundary currents. We briefly describe the well‐known solution of the continuous problem, then employ the finite integration technique as developed by Weiland et al. since 1977 for the solution of the problem. Since this method can be physically realized it offers the possibility to develop special tests in the area of inverse problems. Our main point is to provide a new and rigorous study of convergence for the boundary value problem under consideration. In particular, we will show how the arguments which are used in the proof of the continuous case can be carried over to study the finite‐dimensional numerical scheme. Finally, we will describe a program package which has been developed for the numerical implementation of the scheme using Matlab. Copyright © 2003 John Wiley & Sons, Ltd.
Loss of regularity for the solutions to hyperbolic equations with non‐regular coefficients—an application to Kirchhoff equation
Authors: Hirosawa Fumihiko 
Published: May 2003

AbstractWe consider the Cauchy problem for second‐order strictly hyperbolic equations with time‐depending non‐regular coefficients. There is a possibility that singular coefficients make a regularity loss for the solution. The main purpose of this paper is to derive an optimal singularity for the coefficient that the Cauchy problem is C∞ well‐posed. Moreover, we will apply such a result to the estimate of the existence time of the solution for Kirchhoff equation. Copyright © 2003 John Wiley & Sons, Ltd.
3D FE implementation of an incompressible quadriphasic mixture model
Authors: van Loon R. , Huyghe J. M. , Wijlaars M. W. , Baaijens F. P. T. 
Published: May 2003

AbstractA quadriphasic mixture model, intended to apply to biological tissues, consists of a deforming solid saturated with a fluid, cations and anions. Governing equations of the model are briefly given. The coupled set of differential equations are solved in a finite element method using a weighted residual approach (updated Lagrange). A Newton–Raphson iteration scheme is applied for linearization of the non‐linear set of equations. Interpolation functions are chosen equal to the weighting functions (Galerkin) in discretization. The FE model is then validated for small deformations using the analytical solutions for 1D confined consolidation and swelling. The 3D effects are shown in a swelling cylindrical hydrogel sample. Copyright © 2003 John Wiley & Sons, Ltd.
Elastoplastic stability analysis of shells using the physically stabilized finite element SHB8PS
Authors: Legay Antoine , Combescure Alain 
Published: May 2003

AbstractIn this paper, we present the formulation of the SHB8PS element, its implementation into the incremental, non‐linear and implicit calculation code Stanlax‐INCA and examples of applications which demonstrate its efficiency. This element is an 8‐node, three‐dimensional cube with a preferential direction called the thickness. Therefore, it can be used to represent thin structures while, at the same time, correctly taking into account phenomena throughout the thickness thanks to the use of a numerical integration with five Gauss points in that direction. This element is subintegrated and thus requires a stabilization mechanism in order to control the hourglass modes. The stabilization technique used is based on the works by Belytschko and Bindeman, which apply an ‘assumed strain method’. The main advantage of this element is the adaptivity of its stabilization term, which is made variable with the elastoplastic evolution throughout the thickness. Copyright © 2003 John Wiley & Sons, Ltd.
Implicit time integration for the material point method: Quantitative and algorithmic comparisons with the finite element method
Authors: Guilkey J. E. , Weiss J. A. 
Published: May 2003

AbstractAn implicit integration strategy was developed and implemented for use with the material point method (MPM). An incremental‐iterative solution strategy was developed around Newton's method to solve the equations of motion with Newmark integration to update the kinematic variables. Test problems directly compared the implicit MPM solutions with those obtained using an explicit MPM code and implicit finite element (FE) code. Results demonstrated very good agreement with FE predictions and also illustrated several advantages in comparison to calculations using the explicit MPM code. In particular, the accuracy of the implicit solution was superior to the explicit MPM when compared to validated FE solutions, and by definition the implicit time integration is unconditionally stable. Similarities between the assembly of the implicit MPM equations and those of the FE method were identified and should allow further algorithmic improvement. Copyright © 2003 John Wiley & Sons, Ltd.
Elimination of light‐induced degradation with gallium‐doped multicrystalline silicon wafers
Authors: Dhamrin M. , Hashigami H. , Saitoh T. 
Published: May 2003

AbstractLifetime stability of gallium‐doped multicrystalline silicon wafers has been evaluated under illumination. Quality and stability of the Ga‐doped multicrystalline silicon wafers were intensively studied by means of quasi‐steady‐state photocondcutance lifetime measurement. Results show that as‐grown Ga‐doped multicrystalline silicon wafers have high lifetimes, and no significant degradation was observed under illumination. The Ga‐doped multicrystalline silicon wafers are a promising material for future photovoltaics. Copyright © 2003 John Wiley & Sons, Ltd.
The current–voltage characteristic of the ideal two‐terminal tandem solar cell
Authors: De Vos Alexis 
Published: May 2003

AbstractAn ideal tandem solar cell, with an infinite number of diodes, has the same limit efficiency whether or not the diodes are connected electrically in series. In case of a series connection, the device has a single current–voltage characteristic. The latter can easily be deduced, and its efficiency therefore can easily be calculated. Copyright © 2003 John Wiley & Sons, Ltd.
Self‐efficacy, goal orientation, and fear of failure as predictors of school engagement in high school students
Authors: Caraway Kirsten , Tucker Carolyn M. , Reinke Wendy M. , Hall Charles 
Published: May 2003

AbstractLack of school engagement among adolescents in this country remains a problem that can have very serious consequences including increased risk for school dropout, substance use, teenage pregnancy, and criminal activity. Clearly, identification of psychological variables (self‐variables) of individuals that facilitate or hinder adolescents' levels of school engagement would contribute greatly to the understanding of how to increase adolescents' psychological well‐being and their achievement motivation and associated school engagement. The present study examined the degree of association of three specific self‐variables (self‐efficacy, goal orientation, and fear of failure) with school engagement for high school students. The results and implications for intervention and future research are addressed. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 417–427, 2003.
Differences between WISC‐R and WISC‐III performance scale among children with ADHD
Authors: Mahone E. Mark , Miller Teresa L. , Koth Christine W. , Mostofsky Stewart H. , Goldberg Melissa C. , Denckla Martha B. 
Published: May 2003

AbstractReviews involving the Wechsler Scales for children suggest that Full Scale IQ scores on the Wechsler Intelligence Scale for Children, Third Edition, average 5 to 6 points lower than scores on the second edition of the scale [WISC‐R, Wechsler, D. (1974). Zimmerman & Woo‐Sam, 1997], with the differences distributed disproportionately over subtests, i.e., with larger discrepancies found within the Performance Scale (Wechsler, 1991). Changes on the revised subtests of the WISC‐III Performance Scale may place children with ADHD at a disadvantage compared to their performance on analogous WISC‐R subtests. We examined IQ test performance in 122 unmedicated children with ADHD (61 given the WISC‐R, 61 given the WISC‐III), and 46 children from a healthy, comparison group (23 given the WISC‐R, 23 given the WISC‐III). The ADHD and comparison group samples were matched for sex and for Verbal IQ between WISC‐R and WISC‐III. Children with ADHD had significantly lower Performance IQ on WISC‐III compared to the WISC‐R, with the Picture Arrangement subtest showing the most significant difference. In contrast, there were no significant differences between the WISC‐R and WISC‐III cohorts on Performance IQ or any Performance subtests among the comparison group. These findings highlight the importance of examining the comparability of ability test revisions among clinical and non‐clinical populations, and will be especially salient when the WISC‐III is revised. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 331–340, 2003.
The perceptions, policy, and practice of educating twins: A review
Authors: Beauchamp Heather M. , Brooks Lawrence J. 
Published: May 2003

AbstractTwin births are increasing at a rapid rate, yet many educational personnel throughout the world are unaware of the needs of twins in school. Stereotypical views of twins as pathologically close or excessively dependent pervade educational policies and practices, despite the fact that twins do not differ from singletons on rates of psychological disturbance. Research shows that many schools implement strict policies for classroom placement of twins, yet the effects of such policies on twins' development and educational attainment are currently unknown. Recommendations for school personnel and future directions for this formative area are discussed. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 429–438, 2003.
Particle Imaging Using a Transmission Wide‐Field Phase Confocal Microscope
Authors: Astrakharchik‐Farrimond Eugene , Shekunov Boris Y. , Sawyer Nicolas B. E. , Morgan Stephen P. , Somekh Michael G. , See Chung W. 
Published: May 2003

AbstractA phase‐sensitive wide field transmission microscope, combining the advantages of both interferometric and confocal techniques, has been developed and applied to analysis of particulates, both in dry powder form and in suspensions. The microscope has also been used in detecting defects in crystals. Confocal operation is achieved by superimposing speckle illumination of a reference beam in a Mach‐Zehnder interferometer with a matched speckle pattern of the object beam. It is shown that the phase measurement enables particle size to be determined even when the particle is smaller than the focal spot size. The data acquisition time is below 1ms, making the system suitable for dynamic process measurement. The experimental results are in good agreement with modelled results giving rise to the possibility of simultaneous determination of both the size and refractive index of small particles.
Determination of Soot Particle Size in a Premixed Flame: a Static and Dynamic Light Scattering Study
Authors: Kroner Gert , Fuchs Heribert , Tatschl Reinhard , Glatter Otto 
Published: May 2003

AbstractIn this contribution we report upon our static and dynamic light scattering experiments to characterize soot particles in flames. We studied sooting laminar premixed flame with acetylene as fuel mixed with air as oxidizer. The air equivalence ratio of the combustion was larger than one. We used a Kaskan type burner with circular geometry and a stabilizing flow of nitrogen around the flame. We focused on the determination of the size of the soot particles in the center of the flame as a function of height above burner. In addition we investigated the influence of the mixing ratio of the gases on the size of the particles. Our results show that static light scattering is better suited than dynamic light scattering for a fast and reliable characterization of soot particles in flames. The latter needs detailed a priori information about the flame to allow the unique determination of sizes from the diffusion measurements. The soot particles grow monotonously with height above burner and with decreasing air equivalence ratio. The aggregates have a fractal dimension lower than two.