bluuebunny/crossref_metadata_2025 huggingface dataset:
Stability and accuracy of a semi‐implicit Godunov scheme for mass transport
Authors: Bradford Scott F.
Published: April 2004

Semi‐implicit, Godunov‐type models are adapted for solving the two‐dimensional, time‐dependent, mass transport equation on a geophysical scale. The method uses Van Leer's MUSCL reconstruction in conjunction with an explicit, predictor–corrector method to discretize and integrate the advection and lateral diffusion portions of the governing equation to second‐order spatial and temporal accuracy. Three classical schemes are investigated for computing advection: Lax‐Wendroff, Warming‐Beam, and Fromm. The proposed method uses second order, centred finite differences to spatially discretize the diffusion terms. In order to improve model stability and efficiency, vertical diffusion is implicitly integrated with the Crank–Nicolson method and implicit treatment of vertical diffusion in the predictor is also examined. Semi‐discrete and Von Neumann analyses are utilized to compare the stability as well as the amplitude and phase accuracy of the proposed method with other explicit and semi‐implicit schemes. Some linear, two‐dimensional examples are solved and predictions are compared with the analytical solutions. Computational effort is also examined to illustrate the improved efficiency of the proposed model. Copyright © 2004 John Wiley & Sons, Ltd.
Influence of inertia, topography and gravity on transient axisymmetric thin‐film flow
Authors: Khayat Roger E. , Kim Kyu‐Tae , Delosquer Steven
Published: April 2004

This study examines theoretically the development of early transients for axisymmetric flow of a thin film over a stationary cylindrical substrate of arbitrary shape. The fluid is assumed to emerge from an annular tube as it is driven by a pressure gradient maintained inside the annulus, and/or by gravity in the axial direction. The interplay between inertia, annulus aspect ratio, substrate topography and gravity is particularly emphasized. Initial conditions are found to have a drastic effect on the ensuing flow. The flow is governed by the thin‐film equations of the ‘boundary‐layer’ type, which are solved by expanding the flow field in terms of orthonormal modes in the radial direction. The formulation is validated upon comparison with the similarity solution of Watson (J. Fluid Mech 1964; 20:481) leading to an excellent agreement when only 2–3 modes are included. The wave and flow structure are examined for high and low inertia. It is found that low‐inertia fluids tend to accumulate near the annulus exit, exhibiting a standing wave that grows with time. This behaviour clearly illustrates the difficulty faced with coating high‐viscosity fluids. The annulus aspect is found to be influential only when inertia is significant; there is less flow resistance for a film over a cylinder of smaller diameter. For high inertia, the free surface evolves similarly to two‐dimensional flow. The substrate topography is found to have a significant effect on transient behaviour, but this effect depends strongly on inertia. It is observed that the flow of a high‐inertia fluid over a step‐down exhibits the formation of a secondary wave that moves upstream of the primary wave. Gravity is found to help the film (coating) flow by halting or prohibiting the wave growth. The initial film profile and velocity distribution dictate whether the fluid will flow downstream or accumulate near the annulus exit. Copyright © 2004 John Wiley & Sons, Ltd.
A triangular spectral/hp discontinuous Galerkin method for modelling 2D shallow water equations
Authors: Eskilsson C. , Sherwin S. J.
Published: April 2004

We present a spectral/hp element discontinuous Galerkin model for simulating shallow water flows on unstructured triangular meshes. The model uses an orthogonal modal expansion basis of arbitrary order for the spatial discretization and a third‐order Runge–Kutta scheme to advance in time. The local elements are coupled together by numerical fluxes, evaluated using the HLLC Riemann solver. We apply the model to test cases involving smooth flows and demonstrate the exponentially fast convergence with regard to polynomial order. We also illustrate that even for results of ‘engineering accuracy’ the computational efficiency increases with increasing order of the model and time of integration. The model is found to be robust in the presence of shocks where Gibbs oscillations can be suppressed by slope limiting. Copyright 2004 John Wiley & Sons, Ltd.
A compact numerical algorithm for solving the time‐dependent mild slope equation
Authors: Lin Pengzhi
Published: April 2004

The mild slope equation has been widely used to describe combined wave refraction and diffraction. In this study, a new numerical algorithm is developed to solve the time‐dependent mild slope equation in a second‐order hyperbolic form. The numerical algorithm is based on a compact and explicit finite difference method that is second‐order accurate in both time and space. The algorithm has the similar structure to the leap‐frog method but is constructed on three time levels for the second‐order time derivative term. The numerical model has the capability of simulating transient wave motion by correctly predicting the speed of wave energy propagation, which is important for the real‐time forecast of the arrival time of storm waves generated in the far field. The model is validated against analytical solution for wave shoaling and experimental data for combined wave refraction and diffraction over a submerged elliptic shoal on a slope (Coastal Eng. 1982; 6:255). Lastly, the realistic scale Homma's island (Geophys. Mag. 1950; 21:199) is studied with the use of various wave periods of T = 720s, T = 120 s, and T = 24 s. These wave periods correspond to long, intermediate, and short waves for the given topography, respectively. Comparisons are made between numerical results and existing analytical solutions in terms of the wave amplification around the island, which serves as the indicator for the potential wave runup. Excellent agreements are obtained. The model runs on a PC (Pentium IV 1.8GHz) and the computer capacity allows the computation of a mesh system up to 3000 × 3000, which is equivalent to about 150 × 150 waves or a large area of 540km × 540km for a wave train with the period of T = 60 s. Copyright 2004 John Wiley & Sons, Ltd.
The robustness issue on multigrid schemes applied to the Navier–Stokes equations for laminar and turbulent, incompressible and compressible flows
Authors: Vázquez M. , Ravachol M. , Chalot F. , Mallet M.
Published: April 2004

The paper's leitmotiv is condensed in one word: robustness. This is a real hindrance for the successful implementation of any multigrid scheme for solving the Navier–Stokes set of equations. In this paper, many hints are given to improve this issue. Instead of looking for the best possible speed‐up rate for a particular set of problems, at a given regime and in a given condition, the authors propose some ideas pursuing reasonable speed‐up rates in any situation. In a previous paper, the authors presented a multigrid method for solving the incompressible turbulent RANS equations, with particular care in the robustness and flexibility of the solution scheme. Here, these concepts are further developed and extended to compressible laminar and turbulent flows. This goal is achieved by introducing a non‐linear multigrid scheme for compressible laminar (NS equations) and turbulent flow (RANS equations), taking benefit of a convenient master–slave implementation strategy. Copyright © 2004 John Wiley & Sons, Ltd.
Ordered subset analysis in genetic linkage mapping of complex traits
Authors: Hauser Elizabeth R. , Watanabe Richard M. , Duren William L. , Bass Meredyth P. , Langefeld Carl D. , Boehnke Michael
Published: April 2004

Etiologic heterogeneity is a fundamental feature of complex disease etiology; genetic linkage analysis methods to map genes for complex traits that acknowledge the presence of genetic heterogeneity are likely to have greater power to identify subtle changes in complex biologic systems. We investigate the use of trait‐related covariates to examine evidence for linkage in the presence of heterogeneity. Ordered‐subset analysis (OSA) identifies subsets of families defined by the level of a trait‐related covariate that provide maximal evidence for linkage, without requiring a priori specification of the subset. We propose that examining evidence for linkage in the subset directly may result in a more etiologically homogeneous sample. In turn, the reduced impact of heterogeneity will result in increased overall evidence for linkage to a specific region and a more distinct lod score peak. In addition, identification of a subset defined by a specific trait‐related covariate showing increased evidence for linkage may help refine the list of candidate genes in a given region and suggest a useful sample in which to begin searching for trait‐associated polymorphisms. This method provides a means to begin to bridge the gap between initial identification of linkage and identification of the disease predisposing variant(s) within a region when mapping genes for complex diseases. We illustrate this method by analyzing data on breast cancer age of onset and chromosome 17q [Hall et al., 1990, Science 250:1684–1689]. We evaluate OSA using simulation studies under a variety of genetic models. © 2004 Wiley‐Liss, Inc.
Multivariate linkage analysis of blood pressure and body mass index
Authors: Turner Stephen T. , Kardia Sharon L.R. , Boerwinkle Eric , Andrade Mariza de
Published: April 2004

Multivariate linkage analyses of correlated traits provide greater statistical power to identify genetic loci with effects too small to be detected in single trait analyses. We conducted genomewide multivariate analyses of systolic BP, diastolic BP, and body mass index (BMI) in 1,848 non‐Hispanic white subjects (968 females, 880 males) from 279 multigenerational pedigrees from Rochester, Minnesota. Blood pressure was measured by random zero sphygmomanometer; body mass index was calculated from measurements of height and weight; and genotypes were measured at 520 microsatellite marker loci distributed across the 22 autosomes. Univariate linkage analyses demonstrated tentative evidence of linkage (defined by univariate LOD scores of 1.30–1.99) for diastolic BP on chromosome 18 and for BMI on chromosomes 3, 10, and 18. Bivariate linkage analyses showed tentative evidence of linkage (defined by bivariate LOD scores of 2.06–2.86) for systolic and diastolic BP on chromosome 14 and for either measure of BP and BMI on chromosomes 2, 3, 10, and 18; and suggestive evidence of linkage (defined by bivariate LOD scores of 2.87–3.99) for either measure of BP and BMI on chromosomes 10 and chromosome 15. Trivariate linkage analyses of systolic and diastolic BP and BMI provided evidence of a region influencing all three traits on chromosome 10, where the trivariate LOD score rose to a maximum value of 4.09 (at 144 cM, P=0.0007), and possibly on chromosome 2, where it rose to a maximum value of 2.80 (at 77 cM, P=0.0075). For genomewide linkage analyses to succeed in localizing genes influencing BP, it may be advantageous to exploit the greater statistical power of multivariate linkage analyses to identify loci with pleiotropic effects on correlated traits. © 2004 Wiley‐Liss, Inc.
Optimization of a vacuum freezing cool‐thermal storage coupled with wastewater treatment process
Authors: Chang Cheng‐Liang , Chen Yu‐Zhi , Chang Chih‐Ming
Published: April 2004

Purification of wastewater by freezing under vacuum in a cool‐thermal storage process is investigated. Mathematical models of heat transfer and mass transfer in this system are developed to describe the thickness and the solute distribution of ice as the cool‐thermal storage process proceeds. A mathematical treatment for determining the optimum solidification thickness and operating time to remove the maximum amount of solute is presented. For the system of constant volumetric rate of vacuum, the suction rate is an important factor in determining the efficiency of the process. The suction rate should be kept within the range of 10,000 to 20,000 m3/m2hr when the solute distribution coefficient is less than 1. When the coefficient is greater than 1, the suction rate should be run within 5000 to 10,000 m3/m2hr. Over the proper range of operation, the optimal operating time is a weak function of suction rate. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(3): 189–200, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10134
Advanced bioceramic composite for bone tissue engineering: Design principles and structure–bioactivity relationship
Authors: El‐Ghannam Ahmed R.
Published: April 2004

The synthesis of a new resorbable porous bioactive silica‐calcium phosphate composite (SCPC) that can be used as a tissue‐engineering scaffold for bone regeneration is described. The effects of chemical composition and thermal treatment on crystallization and the mechanism of phase transformation in SCPC were evaluated. In the silica‐rich samples, β‐rhenanite (β‐NaCaPO4) and α‐cristobalite (SiO2) were the dominant phases after treatment at 800°C. On the other hand, in the calcium phosphate‐rich samples, calcium pyrophosphate (Ca2P2O7) was formed in addition to β‐rhenanite and α‐cristobalaite. X‐ray diffraction analyses showed a shift in the 2θ value of the main peak(s) of all phases indicating the formation of solid solutions. Phase transformation reactions were accompanied by a loss of water molecules that contributed to the formation of pores in the size range 10–300 μm. All SCPC samples adsorbed a significantly higher quantity of serum protein than bioactive glass (p < 0.0001). In addition, the silica‐rich SCPC adsorbed a significantly higher amount of serum protein than the calcium phosphate‐rich samples (p < 0.003). While the crystallization of amorphous silica into L‐quartz significantly inhibited serum protein adsorption, the transformation of L‐quartz into α‐cristobalite solid solution (ss) significantly enhanced protein adsorption. On the other hand, in conjunction with the transformation of brushite (CaHPO4) into pyro‐ and tri‐calcium phosphates, there was a significant decrease in protein adsorption. However, as pyro‐ and tri‐calcium phosphates transformed into β‐rhenanite, by thermal treatment, protein adsorption increased markedly. Critical‐size bone defects grafted with silica‐rich SCPC were filled with new bone and contained minimal residues of the graft material. Bone defects grafted with bioactive glass enhanced new bone formation, however, with very limited resorption. The enhanced resorption of SCPC in vivo correlates well with the higher rate of silica dissolution from SCPC than bioactive glass. The facilitated Si dissolution was associated with rapid bone regeneration in defects grafted with SCPC. The enhanced bioactivity properties of the SCPC are due to its chemical composition, modified crystalline structure, and high porosity. The new SCPC may be used for a wide variety of applications in the field of bone reconstruction including tissue‐engineering scaffolds for cell and drug delivery. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 490–501, 2004
β‐Carotene storage, conversion to retinoic acid, and induction of the lipocyte phenotype in hepatic stellate cells
Authors: Martucci Renata B. , Ziulkoski Ana L. , Fortuna Vitor A. , Guaragna Regina M. , Guma Fátima C.R. , Trugo Luiz C. , Borojevic Radovan
Published: April 2004

Hepatic stellate cells (HSCs) are the major site of retinol (ROH) metabolism and storage. GRX is a permanent murine myofibroblastic cell line, derived from HSCs, which can be induced to display the fat‐storing phenotype by treatment with retinoids. Little is known about hepatic or serum homeostasis of β‐carotene and retinoic acid (RA), although the direct biogenesis of RA from β‐carotene has been described in enterocytes. The aim of this study was to identify the uptake, metabolism, storage, and release of β‐carotene in HSCs. GRX cells were plated in 25 cm2 tissue culture flasks, treated during 10 days with 3 μmol/L β‐carotene and subsequently transferred into the standard culture medium. β‐Carotene induced a full cell conversion into the fat‐storing phenotype after 10 days. The total cell extracts, cell fractions, and culture medium were analyzed by reverse phase high‐performance liquid chromatography for β‐carotene and retinoids. Cells accumulated 27.48 ± 6.5 pmol/L β‐carotene/106 cells, but could not convert it to ROH nor produced retinyl esters (RE). β‐Carotene was directly converted to RA, which was found in total cell extracts and in the nuclear fraction (10.15 ± 1.23 pmol/L/106 cells), promoting the phenotype conversion. After 24‐h chase, cells contained 20.15 ± 1.12 pmol/L β‐carotene/106 cells and steadily released β‐carotene into the medium (6.69 ± 1.75 pmol/ml). We conclude that HSC are the site of the liver β‐carotene storage and release, which can be used for RA production as well as for maintenance of the homeostasis of circulating carotenoids in periods of low dietary uptake. © 2004 Wiley‐Liss, Inc.
Assessing compliance with homework assignments: Review and recommendations for clinical practice
Authors: Kazantzis Nikolaos , Deane Frank P. , Ronan Kevin R.
Published: April 2004

Despite the emphasis of homework assignments in psychotherapy research and practice, methods to assess homework compliance have been relatively neglected. This article presents a brief review of 32 studies that described the assessment of homework compliance, and evaluated homework compliance in relation to treatment outcome. More than half of the studies relied on a single source of compliance data (n = 23), eight studies involved retrospective accounts, and only four studies used the same measure of homework compliance. The vast majority of studies focused on the assessment of “homework compliance” without consideration of the “quality of homework completion” or other key factors. A more comprehensive framework for homework compliance is discussed, and a new Homework Rating Scale (HRS) is proposed as the first step towards assisting the field in a more reliable and valid assessment of homework compliance. © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Snow cover in eastern Europe in relation to temperature, precipitation and circulation
Authors: Bednorz Ewa
Published: April 2004

The basic characteristics of snow cover occurrence in eastern Europe are described. For each month from October to May the range of ‘active’ snow‐cover areas in Europe was determined. The boundary criterion for ‘active’ regions was adopted as snow‐cover probability of between 10 and 90%. The correlation coefficients between the snow‐cover characteristics (number of days with snow cover and its monthly mean depth) and other climatic variables (temperature and precipitation) were calculated. A strong positive correlation between the annual number of days with snow cover and the annual number of days with mean temperature <0 °C was discovered for most parts of the study area. A negative correlation between the monthly number of days with snow cover and monthly mean temperature was found and its spatial distribution was analysed. A positive correlation between snow depth and precipitation appeared significant only in some areas. The influence of atmospheric circulation, expressed by North Atlantic oscillation (NAO) index values, on snow cover in the particular months was analysed. The correlation between the number of days with snow cover and the NAO index is large and statistically significant only in central Europe and it becomes insignificant to the east of 30° λ E. High values are noted only in the winter months. In autumn and spring, when the range of the ‘active’ areas moves to the east and the NAO becomes weak, the correlation is very small. Copyright © 2004 Royal Meteorological Society
The development of monthly temperature series for Scotland and Northern Ireland
Authors: Jones P. D. , Lister D.
Published: April 2004

We develop monthly temperature series (mean, maximum and minimum) for the Scottish mainland (SMT), the northern and northwestern Scottish Isles (SIT, Orkneys, Shetlands and Outer Hebrides) and for Northern Ireland (NIT). The series were developed from eight long station records, five over SMT, two for SIT and one for NIT. The series are reliable back to 1866 for all three regions, but extensions to 1800 and 1827 for SMT and SIT are less so, likely due to direct solar insolation effects in the summer months. All three regions show long‐term statistically significant seasonal warming over both 1861–2000 and 1901–2000, except for the winter season. For the calendar year, the temperature change explained by a linear trend over 1861–2000 is 0.69°C, 0.64°C and 0.77°C for SMT, SIT and NIT respectively. Of the 51 (12 months + 4 seasons + annual = 17 × 3 regions) warmest values, 23 have occurred after 1987. Of the coldest extremes, 30 occurred between 1861 and 1899 and the last cold extreme months were in 1952. Copyright © 2004 Royal Meteorological Society
Spatial and temporal variability of the daily rainfall regime in Catalonia (northeastern Spain), 1950–2000
Authors: Lana X. , Martínez M.D. , Serra C. , Burgueño A.
Published: April 2004

Spatial and temporal patterns in the daily rainfall regime of Catalonia (northeastern Spain) recorded for the 1950–2000 period are analysed from several points of view, including the irregularity of the time series in terms of entropy, the Mann–Kendall test for time trends, a principal component analysis (PCA), an average linkage (AL) clustering algorithm and, finally, a power spectrum analysis, which includes a comparison of white‐noise and Markovian red‐noise hypotheses. The analyses are based on three monthly variables derived from the amounts recorded on a daily basis: the average daily rainfall and the standard deviation of the daily rainfall for each month, together with the corresponding coefficient of variation. The joint spatial–temporal variability is manifested by the irregularity index, which is characterized by relevant values in all cases and gradients from the north (Pyrenees and Pre‐Pyrenees mountain ranges) to the south (Ebro Valley) and to the Mediterranean coast. The interpretation of the factor scores derived from the PCA and of the clusters obtained from the AL algorithm also describes the complex spatial distribution of the daily rainfall regime, given that the effects of atmospheric circulation patterns on rainfall regimes are conditioned by the complex orography of Catalonia and its proximity to the Mediterranean Sea. The factor loadings associated with the PCA also suggest a distinction between hot, cold and mild seasons. Finally, it is worth noting that monthly series are usually accompanied by white background noise and, in a few cases, signs of Markovian behaviour and some significant periodicities, which are generally of less than 10 months and which change from one cluster to another. Copyright © 2004 Royal Meteorological Society
The scaling law relating world point‐precipitation records to duration
Authors: Galmarini S. , Steyn D. G. , Ainslie B.
Published: April 2004

In order to understand the remarkable six‐orders of magnitude scaling law underlying worldwide point‐precipitation records, we analyse precipitation data from a wide range of stations worldwide. The analysis shows that single‐exponent scaling laws exist only for single stations experiencing extremely high precipitation. This analysis, and a consideration of the sequence of earlier published precipitation records, leads us to conclude that record precipitation exists because of an optimization of all factors leading to precipitation. This idea is incorporated into a scheme for simulating the record–duration curve for precipitation, which utilizes only the probability distribution function for precipitation amounts, the temporal autocorrelation of precipitation and a starting record–duration point. The simulation suggests record precipitation is asymptotically independent of most underlying physical processes. Copyright © 2004 Royal Meteorological Society
Water vapour transport associated with tropical–temperate trough systems over southern Africa and the southwest Indian Ocean
Authors: Todd Martin C. , Washington Richard , Palmer Paul I.
Published: April 2004

Tropical–temperate trough (TTT) systems are the dominant rain‐producing synoptic type over southern Africa. They represent an important mechanism of poleward transport of energy and momentum. This paper provides an analysis of water vapour transport in TTT systems. An objective sampling of TTT systems is conducted from analysis of daily satellite rainfall products. During the sampled TTT events, rain bands extend from tropical southern Africa near 10 °S to the midlatitudes of the southwest Indian Ocean. The divergent and non‐divergent (streamfunction) components of vertically integrated water vapour flux associated with major TTT events are calculated, from National Centers for Environmental Prediction reanalysis data. During TTT events the streamfunction circulation dominates water vapour transport, although adjustments to the divergent component are relatively more important. The results indicate that TTT events facilitate a substantial water vapour flux from the tropics into the midlatitudes. Water vapour transport to the midlatitudes along the TTT axis is facilitated largely by changes to the streamfunction, associated with a strengthening and eastward displacement of the Indian Ocean high, and the advent of midlatitude transients. It is also shown that TTT systems are major regions of moisture convergence. The high vapour concentrations along the full extent of the TTT rain bands are maintained by the divergent circulation. The structure of these divergent vapour flux anomalies is suggestive of adjustments to the Walker circulation, involving strong anomalous divergence over the maritime continent/west Pacific and a weaker enhancement of the major divergence centre over the tropical Atlantic. Copyright © 2004 Royal Meteorological Society
A model intercomparison study of climate change‐signals in extratropical circulation
Authors: Rauthe Monika , Hense Andreas , Paeth Heiko
Published: April 2004

Since 1970, the observed time series of various extratropical circulation modes have revealed remarkable trends. In many studies it has been suggested that these trends may be related to global warming due to increasing greenhouse gas (GHG) concentrations. Coupled climate model scenario experiments may give a hint of such a relationship. Here, a large model intercomparison study is presented, incorporating most state‐of‐the‐art models of the international modeller community with GHG and GHG plus sulphate aerosol (SUL) forcing, in order to quantify the signals common to different climate models and to determine the degree of uncertainty. The extratropical circulation candidates are the Arctic oscillation (AO), the North Atlantic oscillation (NAO), the Aleutian low (AL) and the Antarctic oscillation (AAO).

Most climate models agree in predicting positive AO and AAO trends into the 21st century, these being different from the respective results of long‐term control experiments. The NAO appears to be less sensitive to radiative forcing, with slightly positive and negative trends occurring in different models. The AL tends to strengthen in several models with GHG + SUL forcing. Projecting the spatial structure of the circulation modes onto the trend patterns of mean sea‐level pressure (SLP) indicates that, in particular, the AO and AAO contribute considerably to the simulated long‐term trends in SLP. Intermodel variations in Northern Hemisphere SLP trends become predominantly apparent over the mountainous regions and the North Pacific. In the Southern Hemisphere, the Antarctic region is subject to large model uncertainties. The multi‐decadal trends of all circulation modes except the NAO are statistically significant in the majority of the climate‐change experiments. At the interannual time scale, external radiative forcing does account for a small but statistically significant part of total multi‐model variability, but this part is of the same order of magnitude as the systematic differences between the models. At decadal time scales, the external impact clearly stands out from the other sources of variability. Present‐day climate models mostly agree in predicting a strengthening of the annular modes AO and AAO. As all models generally project a deepening of SLP over the polar caps, time series indicative of these regions might be a more appropriate measure of the sensitivity of extratropical circulation. Copyright © 2004 Royal Meteorological Society
Effects of stereotactic neurosurgery on postural instability and gait in Parkinson's disease
Authors: Bakker Maaike , Esselink Rianne A.J. , Munneke Marten , Limousin‐Dowsey Patricia , Speelman Hans D. , Bloem Bastiaan R.
Published: April 2004

Postural instability and gait disability (PIGD) are disabling signs of Parkinson's disease. Stereotactic surgery aimed at the internal globus pallidus (GPi) or subthalamic nucleus (STN) might improve PIGD, but the precise effects remain unclear. We performed a systematic review of studies that examined the effects of GPi or STN surgery on PIGD. Most studies examined the effects of bilateral GPi stimulation, bilateral STN stimulation, and unilateral pallidotomy; we, therefore, only performed a meta‐analysis on these studies. Bilateral GPi stimulation, bilateral STN stimulation, and to a lesser extent, unilateral pallidotomy significantly improved PIGD, and more so during the ON phase than during the OFF phase. © 2004 Movement Disorder Society
Cigarette smoking in Parkinson's disease: Influence on disease progression
Authors: Alves Guido , Kurz Martin , Lie Stein A. , Larsen Jan P.
Published: April 2004

Previous studies have shown an inverse association between smoking and the prevalence of Parkinson's disease (PD), suggesting that smoking may induce a biological protection against nigral neuronal damage. In 1993, we examined the frequency of cigarette smokers among 239 patients with PD and two control groups. In addition, the progression of parkinsonism and other clinical features were followed prospectively in smoking and nonsmoking PD patients over an 8‐year period. Mortality in the two PD groups was also examined. We found a 50% higher prevalence of smokers in the control groups than in patients with PD. In contrast, during the follow‐up period, there were no significant differences in progression of parkinsonism, cognitive impairment, and mood in smoking and nonsmoking patients with PD. Mortality was also similar in the two groups. The lack of influence on disease progression may indicate that cigarette smoking does not have a major neuroprotective effect in patients with already diagnosed PD. © 2004 Movement Disorder Society
Development of donor‐specific chimerism and tolerance in composite tissue allografts under αβ‐T‐cell receptor monoclonal antibody and cyclosporine a treatment protocols
Authors: Ozer Kagan , Izycki Dariusz , Zielinski Maciej , Siemionow Maria
Published: April 2004

Recently, we induced donor‐specific tolerance to rat hindlimb allografts under a 35‐day course of αβ‐T‐cell receptor monoclonal antibody (αβ‐TCR mAb) and cyclosporine A (CsA). In this report, we investigated the role of shorter αβ‐TCR/CsA protocols on tolerance induction. We performed 52 hindlimb transplantations, between Lewis‐Brown‐Norway (LBN, F1) donors and Lewis recipients to test the impact of 21‐, 7‐, and 5‐day protocols of combined αβ‐TCR/CsA treatment on tolerance induction. Donor‐specific tolerance and immunocompetence were tested by mixed lymphocyte reaction (MLR) in vitro and by standard skin grafting in vivo. The efficacy of immunosuppressive protocol and donor‐specific chimerism was assessed by flow cytometry. All transplants under 5, 7, and 21 days of combined αβ‐TCR/CsA therapy survived over 350 days. Clinical tolerance and immunocompetence were confirmed by skin grafting in vivo and MLR in vitro. Flow cytometry revealed a high level of donor chimerism in the peripheral blood of long‐term survivors. The extention of survival of limb allografts and allo‐unresponsiveness were directly associated with the development of stable chimerism in the tolerant recipients. © 2004 Wiley‐Liss, Inc.
The complete classification of flaps
Authors: Hallock Geoffrey G.
Published: April 2004

Whereas the permutations and combinations in our arsenal of free flaps continue to increase exponentially, the lack of a coherent nomenclature system has caused this often to appear as only a haphazard array of bewildering possibilities. A simplified nomenclature schema is essential to enhance the acceptance and universal application of, as well as accurately describe, many of these new flap options. A minor modification of prior anatomical systems that incorporates all possible distinguishing characteristics in describing any given flap is an intrinsic part of the system, but the primary focus in flap identification is centered around its vascular supply. Several examples are given to illustrate how the complete classification of every free flap can be possible in a reproducible and highly interpretable fashion. © 2004 Wiley‐Liss, Inc.
The maximum‐leaf spanning tree problem: Formulations and facets
Authors: Fujie Tetsuya
Published: April 2004

The Maximum Leaf Spanning Tree Problem (MLSTP) is to find a spanning tree in a given undirected graph, whose number of leaves (vertices of degree 1) is maximum. In this article, we consider an integer programming approach to the MLSTP. We provide two formulations of the MLSTP and study the facial structure of polytopes arising from the formulations. Moreover, several relaxation problems are compared. © 2004 Wiley Periodicals, Inc.
A directed cycle‐based column‐and‐cut generation method for capacitated survivable network design
Authors: Rajan Deepak , Atamtürk Alper
Published: April 2004

A network is said to be survivable if it has sufficient capacity for rerouting all of its flow under the failure of any one of its edges. Here, we present a polyhedral approach for designing survivable networks. We describe a mixed‐integer programming model, in which sufficient slack is explicitly introduced on the directed cycles of the network while flow routing decisions are made. In case of a failure, flow is rerouted along the slacks reserved on directed cycles. We give strong valid inequalities that use the survivability requirements. We present a computational study with a column‐and‐cut generation algorithm for designing capacitated survivable networks. © 2004 Wiley Periodicals, Inc.
Developmental regulation of spine and filopodial motility in primary visual cortex: Reduced effects of activity and sensory deprivation
Authors: Konur Sila , Yuste Rafael
Published: April 2004

Dendritic protrusions are highly motile during postnatal development. Although spine morphological plasticity could be associated with synaptic plasticity, the function of rapid spine/filopodial motility is still unknown. To investigate the role of spine motility in the development of the visual cortex and its relation with critical periods, we used two‐photon imaging of neurons from layers receiving visual input in developing mouse primary visual cortex and compared motility between control and visually deprived animals. Spine and filopodia motility was prominent during early synaptogenesis (P11–P13) but greatly decreased after P15. This “switch” was coincident with a 2.5‐fold increase in protrusion density and spine formation. Spine motility was not regulated during the critical period for monocular deprivation (P19–P34). Moreover, delaying the critical period by dark rearing did not delay the normal developmental decrease of spine motility, but caused a modest further reduction in motility at P28–P35. Dark rearing and enucleation also mildly reduced spine motility before eye opening and dark rearing reduced the proportion of filopodia. We conclude that (1) rapid spine motility is not related to critical period plasticity, but is likely to play a role in early synaptogenesis, and (2) neuronal activity stimulates spine motility during synaptogenesis and promotes the appearance of dendritic filopodia. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 236–246, 2004
Use of targetable gfp‐tagged neuropeptide for visualizing neuropeptide release following execution of a behavior
Authors: Husain Qasim M. , Ewer John
Published: April 2004

Previous work has shown that a transgene consisting of a fusion between the rat atrial natriuretic peptide and a green fluorescent protein reporter (ANF‐gfp) is processed, localized, and released, as would be an endogenous neuropeptide when it is expressed in the nervous system ofDrosophila melanogasterusing the GAL4/UAS expression system. Here we have tested the utility of this targetable transgene for detecting neuropeptide release following the execution of a peptide‐controlled behavior. For the behavior we used ecdysis, the behavior expressed by insects to shed their old cuticle at the end of the molt. We found that larval ecdysis was accompanied by a readily detectable reduction in gfp fluorescence from relevant secretory cells in the periphery and peptidergic neurons in the CNS. We also found that expression of the ANF‐gfp products did not have detrimental effects on larval ecdysis or adult circadian rhythmicity, when the transgene was expressed in peptidergic cells that are known to control these behaviors. Finally, we used a broadly expressed GAL4 driver to show that the UAS‐ANF‐gfp transgene could be used to identify axons that show a reduction in gfp fluorescence following the expression of ecdysis behavior. These findings, coupled with the availability of an increasing number of strains bearing different GAL4 drivers, suggest that this transgene will be a useful tool for identifying peptidergic neurons and secretory cells (and, eventually, their secretory product) that release their peptide content during the occurrence, in the intact animal, of a developmental, physiological or behavioral process of interest. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 181–191, 2004
Ethanol exposure alters neurotrophin receptor expression in the rat central nervous system: Effects of prenatal exposure
Authors: Blaine Moore D. , Madorsky Irina , Paiva Michael , Barrow Heaton Marieta
Published: April 2004

Developmental ethanol exposure produces significant central nervous system (CNS) abnormalities. The cellular mechanisms of ethanol neurotoxicity, however, remain elusive. Recent data implicate altered neurotrophin signaling pathways in ethanol‐mediated neuronal death. The present study investigated ethanol‐induced alterations in neurotrophin receptor proteins in the rat CNS following chronic ethanol treatment during gestation, via liquid diet to pregnant dams. Brains were dissected on P1 and P10, and Western blots for the neurotrophin receptors TrkA, TrkB, TrkC, and p75 were quantified. Such ethanol treatment produced significant changes in neurotrophin receptor levels in the hippocampus, septum, cerebral cortex, and cerebellum. Receptor levels in hippocampus, septum, and cerebellum, tended to be decreased, while levels in cortex were consistently increased. Males were generally more affected than females. While most of these alterations were transient, sustained or delayed changes were present in P10 septum, cortex, and cerebellum. These results indicate that developmental ethanol exposure produces major changes in the normal physiological levels of the neurotrophin receptors throughout the CNS. These changes in the receptor complement during critical prenatal stages could relate to the anomalous development of the CNS seen in the fetal alcohol syndrome. This relationship is discussed, together with the potential biological effects of such dramatic changes in neurotrophin receptor expression. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 101–113, 2004
Ethanol exposure alters neurotrophin receptor expression in the rat central nervous system: Effects of neonatal exposure
Authors: Moore D. Blaine , Madorsky Irina , Paiva Michael , Barrow Heaton Marieta
Published: April 2004

The detrimental effects of ethanol exposure during nervous system development have been well established. The cellular mechanisms of ethanol neurotoxicity, however, have not been clearly defined. Recent studies suggest that neurotrophin signaling pathways may be involved in ethanol‐mediated neuronal death. The present investigation, therefore, was designed to examine ethanol‐induced alterations in neurotrophin receptor protein levels in the developing central nervous system (CNS) following chronic ethanol treatment administered during the early neonatal period. For this study, rats were exposed to ethanol via vapor inhalation from postnatal day 4 (P4) to P10. Brains were then dissected on P10 or P21, and Western blots used to quantify expression of neurotrophin receptors TrkA, TrkB, TrkC, and p75. This early postnatal ethanol treatment produced significant alterations in receptor levels in hippocampus, septum, cerebral cortex, and cerebellum. The alterations seen were variable, with decreases generally found in hippocampus and cerebellum, increases noted in septum, and changes in both directions occurring in cortex. These alterations were generally more prevalent in males than in females. While most of the receptor changes observed were transient, sustained or delayed alterations were occasionally seen in hippocampus, cortex, and cerebellum. These results suggest that developmental ethanol exposure modulates expression of these neurotrophin receptors throughout the CNS, alterations which could have wide‐ranging effects on functional CNS development. The possible linkage between such changes and abnormalities encountered in the fetal alcohol syndrome are considered. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 114–126, 2004
A weak‐derivative form for linear hyperbolic systems
Authors: Cooke Charlie H. , Chen Tze‐Jang
Published: April 2004

Difference schemes for linear hyperbolic systems are considered. As a main result, a weak derivative form (WDF) of the governing equations is derived, which is also valid near flow discontinuities. The occurrence of one‐sided derivatives in the WDF structure indicated how to difference near discontinuities. When first‐order differencing is applied to the WDF result, the (linearly identical) schemes by Godunov, Roe, and Steger‐Warming are reproduced. The extension to nonlinear systems is via a local linearization. Choosing Roe's averaging reduces the WDF algorithm to Roe's scheme, whereas other nonlinear WDF schemes are possible. The suitability of various kinds of averaging is numerically investigated. For weak shocks a surprising lack of sensitivity of the method to a particular averaging is exhibited. However, for strong shocks and where the ordinary arithmetic average is used, a slightly more pronounced difference in performance exists between Roe's scheme and WDF. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004
An error estimate for finite volume methods for the Stokes equations on equilateral triangular meshes
Authors: Blanc Philippe , Eymard Robert , Herbin Raphaèle
Published: April 2004

We give here an error estimate for a finite volume discretization of the Stokes equations in two space dimensions on equilateral triangular meshes. This work was initiated by an analogous result presented by Alami‐Idrissi and Atounti for general triangular meshes. However, in this latter article, the result is not actually proven. We state here the restricting assumptions (namely equilateral triangles) under which the error estimate holds, using the tools which were introduced by Eymard, Gallouet and Herbin and used by Alami‐Idrissi and Atounti. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004
Functional and molecular characterization of interleukin‐2 transgenic Ewing tumor cells for in vivo immunotherapy
Authors: Staege Martin S. , Hansen Gesine , Baersch Gudrun , Burdach Stefan
Published: April 2004

Background

Interleukin‐2 (IL‐2) is a potent cytokine with potential activity against several tumors including Ewing tumors (ET). Side effects of systemic IL‐2 can be circumvented by the use of transgenic tumor cells. However, in vitro manipulation may change the overall gene expression profile of tumor cells unfavorably. Therefore, we assessed gene expression profiles, safety, and immunomodulatory efficacy of IL‐2 transgenic (IL‐2‐tg) ET cells in vitro and in NOD/scid mice.

Procedure

Viable wild type A673 tumor cells were co‐cultured together with irradiated IL‐2‐tg or mock‐transfected cells and HLA matched peripheral blood mononuclear cells. Activation of T and NK cells was assessed by FACS analysis. The effect of irradiated IL‐2‐tg cells on tumor growth in vivo was investigated by using NOD/scid mice. Gene expression profiles of wild type and transfected cells were analyzed with Affymetrix HG‐U95A microarrays.

Results

IL‐2‐tg cells activated and in creased the number of T cells and NK cells in vitro. Co‐culture with IL‐2‐tg but not with mock‐transfected cells almost completely suppressed wild type tumor cell growth in vitro. Cell depletion experiments indicated a major contribution of NK cells to this tumor cell suppression. Co‐transfer of irradiated IL‐2‐tg cells significantly reduced wild type tumor growth in NOD/scid mice. Side effects in the treated animals were not observed and no tumor growth was observed after injection of irradiated IL‐2‐tg cells alone. Gene expression profiling revealed a substantial degree of homogeneity of gene expression in transfected and wild type cells and suggests that transfection and selection procedures had no major impact on the gene expression profile.

Conclusions

Next to a high degree of homogeneity between transgenic and wild type cells, our data suggest that irradiated IL‐2‐tg ET cells can activate cytolytic effector cells. These cells may have therapeutic potential for ET patients. © 2004 Wiley‐Liss, Inc.
Residual stresses, shrinkage, and warpage of complex injection molded products: Numerical simulation and experimental validation
Authors: Kabanemi K. K. , Vaillancourt H. , Wang H. , Salloum G.
Published: April 2004

A numerical simulation model for predicting residual stresses and residual deformations which arise during the injection molding of thermoplastic polymers in the post‐packing stage has been developed. A thermoviscoelastic model with volume relaxation is used for the calculation of residual stresses. The finite element method employed is based on the theory of shells as an assembly of flat elements. This theory is well suited for thin injection molded products of complex shape. The approach allows the prediction of residual deformations and residual stresses layer by layer like a truly three‐dimensional calculation, while reducing the computational cost significantly. The hole drilling technique is used to measure the residual stresses across the thickness of the product. A three‐dimensional laser digitizing system, an image processing technique and a dual displacement transducer system are used to measure the warpage. Experiments are carried out on polycarbonate and high density polyethylene parts. Numerical results are in qualitative agreement with experimental observations, i.e., the skin of the box is surrounded by a compressive region while the core region is in traction. The trend of both the experimental and the predicted residual stress profiles is close. Different examples are presented to illustrate the influence of the geometrical complexity of the shape on the final deformations and residual stresses. The influence of the mold temperature on residual stresses and warpage is also analyzed.