bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analytical integrations in 2D BEM elasticity
Authors: Salvadori Alberto 
Published: October 2002

AbstractIn the context of two‐dimensional linear elasticity, this paper presents the closed form of the integrals that arise from both the standard (collocation) boundary element method and the symmetric Galerkin boundary element method. Adopting polynomial shape functions of arbitrary degree on straight elements, finite part of Hadamard, Cauchy principal values and Lebesgue integrals are computed analytically, working in a local coordinate system. For the symmetric Galerkin boundary element method, a study on the singularity of the external integral is conducted and the outer weakly singular integral is analytically performed. Numerical tests are presented as a validation of the obtained results. Copyright © 2001 John Wiley & Sons, Ltd.
Arbitrary Lagrangian–Eulerian (ALE) formulation for hyperelastoplasticity
Authors: Rodríguez‐Ferran Antonio , Pérez‐Foguet Agustí , Huerta Antonio 
Published: October 2002

AbstractThe arbitrary Lagrangian–Eulerian (ALE) description in non‐linear solid mechanics is nowadays standard for hypoelastic–plastic models. An extension to hyperelastic–plastic models is presented here. A fractional‐step method—a common choice in ALE analysis—is employed for time‐marching: every time‐step is split into a Lagrangian phase, which accounts for material effects, and a convection phase, where the relative motion between the material and the finite element mesh is considered. In contrast to previous ALE formulations of hyperelasticity or hyperelastoplasticity, the deformed configuration at the beginning of the time‐step, not the initial undeformed configuration, is chosen as the reference configuration. As a consequence, convecting variables are required in the description of the elastic response. This is not the case in previous formulations, where only the plastic response contains convection terms. In exchange for the extra convective terms, however, the proposed ALE approach has a major advantage: only the quality of the mesh in the spatial domain must be ensured by the ALE remeshing strategy; in previous formulations, it is also necessary to keep the distortion of the mesh in the material domain under control. Thus, the full potential of the ALE description as an adaptive technique can be exploited here. These aspects are illustrated in detail by means of three numerical examples: a necking test, a coining test and a powder compaction test. Copyright © 2001 John Wiley & Sons, Ltd.
A simple algorithm for localized construction of non‐matching structural interfaces
Authors: Park K. C. , Felippa C. A. , Rebel G. 
Published: October 2002

AbstractA simple and effective algorithm for the modular construction of non‐matched interfaces is presented for the partitioned solution of large‐scale structural problems. The formulation is based on a recently developed four‐field variational principle, which introduces a connection frame between the interfaced partitions. A key result of the present study is a frame nodal placement criterion that uniquely determines the frame discretization into piecewise linear elements so that the interface patch test condition is satisfied a priori. The method is demonstrated with several 2D and 3D example problems. Copyright © 2002 John Wiley & Sons, Ltd.
An hp‐adaptive finite element method for electromagnetics—part II: A 3D implementation
Authors: Rachowicz W. , Demkowicz L. 
Published: October 2002

AbstractThis is the second of papers describing implementations of the hp‐adaptive, mixed finite element (FE) method for the solution of steady‐state Maxwell's equations proposed in Demkowicz and Vardapetyan (Comput. Methods Appl. Mech. Engng. 1998; 152(1–2):103–124). The paper presents a three‐dimensional version of the method based on hexahedral elements of possibly variable order. The elements can be subsected (isotropically or anisotropically), and their orders can be enriched, which allows for non‐uniform distribution of element sizes h and orders p—the hp adaptation. A few numerical examples illustrate the capability of the method. Copyright © 2001 John Wiley & Sons, Ltd.
A 3D brick element based on Hu–Washizu variational principle for mesh distortion
Authors: Cao Yan Ping , Hu Ning , Lu Jian , Fukunaga Hisao , Yao Zhen Han 
Published: October 2002

AbstractIn order to improve the accuracy of the mixed element for irregular meshes, a penalty‐equilibrating 3D‐mixed element based on the Hu–Washizu variational principle has been proposed in this paper. The key idea in this work is to introduce a penalty term into the Hu–Washizu three‐field functional, which can enforce the stress components to satisfy the equilibrium equations in a weak form. Compared with the classical hybrid and mixed elements, this technique can efficiently reduce the sensitivity of the element to mesh distortion. The reason for the better results of this penalty technique has been investigated by considering a simple 2D problem. From this investigation, it has been found that the penalty parameter here plays the role of a scaling factor to reduce the influence of the parasitic strain or stress, which is similar to the devised selective scaling factor proposed by Sze. Furthermore, compared with the hybrid stress element, the proposed element based on the three‐field variational principle is more suitable for material non‐linear analysis. Numerical examples have demonstrated the improved performance of the present element, especially in stress computation when FEM meshes are irregular. Copyright © 2002 John Wiley & Sons, Ltd.
Classical and advanced multilayered plate elements based upon PVD and RMVT. Part 2: Numerical implementations
Authors: Carrera Erasmo , Demasi Luciano 
Published: October 2002

AbstractThis paper presents numerical evaluations related to the multilayered plate elements which were proposed in the companion paper (Part 1). Two‐dimensional modellings with linear and higher‐order (up to fourth order) expansion in the z‐plate/layer thickness direction have been implemented for both displacements and transverse stresses. Layer‐wise as well as equivalent single‐layer modellings are considered on both frameworks of the principle of virtual displacements and Reissner mixed variational theorem. Such a variety has led to the implementation of 22 plate theories. As far as finite element approximation is concerned, three quadrilaters have been considered (four‐, eight‐ and nine‐noded plate elements). As a result, 22×3 different finite plate elements have been compared in the present analysis. The automatic procedure described in Part 1, which made extensive use of indicial notations, has herein been referred to in the considered computer implementations. An assessment has been made as far as convergence rates, numerical integrations and comparison to correspondent closed‐form solutions are concerned. Extensive comparison to early and recently available results has been made for sample problems related to laminated and sandwich structures. Classical formulations, full mixed, hybrid, as well as three‐dimensional solutions have been considered in such a comparison. Numerical substantiation of the importance of the fulfilment of zig‐zag effects and interlaminar equilibria is given. The superiority of RMVT formulated finite elements over those related to PVD has been concluded.Two test cases are proposed as ‘desk‐beds’ to establish the accuracy of the several theories. Results related to all the developed theories are presented for the first test case. The second test case, which is related to sandwich plates, restricts the comparison to the most significant implemented finite elements. It is proposed to refer to these test cases to establish the accuracy of existing or new higher‐order, refined or improved finite elements for multilayered plate analyses. Copyright © 2002 John Wiley & Sons, Ltd.
Arbitrary order edge elements for electromagnetic scattering simulations using hybrid meshes and a PML
Authors: Ledger P. D. , Morgan K. , Hassan O. , Weatherill N. P. 
Published: October 2002

AbstractThe use of arbitrary order edge elements for the simulation of two‐dimensional electromagnetic scattering problems on hybrid meshes of triangles and quadrilaterals is described. Single‐frequency incident waves, generated by a source in the far field, are considered and the solution is determined in the frequency domain. For numerical simulation, the solution domain is truncated at a finite distance from the perfectly conducting scatterer and the non‐reflecting boundary condition at the truncated boundary is imposed by the use of a perfectly matched layer (PML). Several examples are included to demonstrate the performance of the proposed procedure. Copyright © 2002 John Wiley & Sons, Ltd.
The probability approach to numerical solution of nonlinear parabolic equations
Authors: Milstein G. N. 
Published: October 2002

AbstractA number of new layer methods for solving semilinear parabolic equations and reaction‐diffusion systems is derived by using probabilistic representations of their solutions. These methods exploit the ideas of weak sense numerical integration of stochastic differential equations. In spite of the probabilistic nature these methods are nevertheless deterministic. A convergence theorem is proved. Some numerical tests are presented. © 2002 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 18: 490–522, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/num.10020
Cancer as an epigenetic disease: DNA methylation and chromatin alterations in human tumours
Authors: Esteller Manel , Herman James G. 
Published: October 2002

AbstractCancer is an epigenetic disease at the same level that it can be considered a genetic disease. In fact, epigenetic changes, particularly DNA methylation, are susceptible to change and are excellent candidates to explain how certain environmental factors may increase the risk of cancer. The delicate organization of methylation and chromatin states that regulates the normal cellular homeostasis of gene expression patterns becomes unrecognizable in the cancer cell. The genome of the transformed cell undergoes simultaneously a global genomic hypomethylation and a dense hypermethylation of the CpG islands associated with gene regulatory regions. These dramatic changes may lead to chromosomal instability, activation of endogenous parasitic sequences, loss of imprinting, illegitimate expression, aneuploidy, and mutations, and may contribute to the transcriptional silencing of tumour suppressor genes. The hypermethylation‐associated inactivation affects virtually all of the pathways in the cellular network, such as DNA repair (hMLH1, BRCA1, MGMT, …︁), the cell cycle (p16INK4a, p14ARF, p15INK4b, …︁), and apoptosis (DAPK, APAF‐1, …︁). The aberrant CpG island methylation can also be used as a biomarker of malignant cells and as a predictor of their behaviour, and may constitute a good target for future therapies. Copyright © 2002 John Wiley & Sons, Ltd.
Overexpression of peroxiredoxins I, II, III, V, and VI in malignant mesothelioma
Authors: Kinnula V. L. , Lehtonen S. , Sormunen R. , Kaarteenaho‐Wiik R. , Kang S. W. , Rhee S. G. , Soini Y. 
Published: October 2002

AbstractPeroxiredoxins (Prxs) are a recently characterized group of thiol‐containing proteins with efficient antioxidant capacity, capable of consuming hydrogen peroxide in living cells. Altogether six distinct Prxs have been characterized in mammalian tissues. Their expression was investigated in histological samples of mesothelioma and in cell lines established from the tumours of mesothelioma patients. Four cases with histopathologically healthy pleura from non‐smokers were used as controls. Healthy pleural mesothelium was negative or very weakly positive for all Prxs. In mesothelioma, the most prominent reactivity was observed with Prxs I, II, V, and VI. Prx I was highly or moderately expressed in 25/36 cases, the corresponding figures for Prxs II–VI being 27/36 (Prx II), 13/36 (Prx III), 2/36 (Prx IV), 24/36 (Prx V), and 30/36 (Prx VI). Positive staining was observed both in the cytosolic and the nuclear compartment, with the exception of Prx III, which showed no nuclear reactivity. The staining pattern of Prxs III and V was granular. Immunoelectron microscopic localization of Prxs was in accordance with the immunohistochemical findings, showing diffuse cytoplasmic localization for Prxs I, II, IV, and VI and distinct mitochondrial labelling for Prxs III and V. There was no significant association between the extent of staining and different Prxs. It appeared that Prxs may not have prognostic significance, but being prominently expressed in most mesotheliomas these proteins, at least in theory, may play a role in the primary drug resistance of this disease. Copyright © 2002 John Wiley & Sons, Ltd.
Current understanding of cellular and molecular events in intervertebral disc degeneration: implications for therapy
Authors: Freemont A. J. , Watkins A. , Le Maitre C. , Jeziorska M. , Hoyland J. A. 
Published: October 2002

AbstractUntil recently, material removed from the intervertebral disc (IVD) at surgery consisted either of ‘loose bodies’ from the centre of the IVD or discal tissue displaced (prolapsed) into the intervertebral root or spinal canals. This material is best regarded as a by‐product of disc degeneration and therefore not representative of the disease process itself. Recent advances in surgical techniques, particularly anterior fusion, in which large segments of the anterior part of the IVD are excised with the anatomical relationships between different components intact, have generated material that can be investigated with modern molecular and cell biological techniques. This is an important area of study because degeneration of the lumbar IVDs is associated, perhaps causally, with low back pain, one of the most common and debilitating conditions in the West. ‘Degeneration’ carries implications of inevitable progression of wear‐and‐tear associated conditions. Modern research on human IVD tissue has shown that this is far from the case and that disruption of the micro‐anatomy described as degeneration is an active process, regulated by locally produced molecules. The exciting consequence of this observation is the possibility of being able to inhibit or even reverse the processes of degeneration using targeted therapy. Copyright © 2002 John Wiley & Sons, Ltd.
Analysis of key cell‐cycle checkpoint proteins in colorectal tumours
Authors: McKay Judith A. , Douglas Joy J. , Ross Val G. , Curran Stephanie , Loane Joseph F. , Ahmed Fareeda Y. , Cassidy Jim , McLeod Howard L. , Murray Graeme I. 
Published: October 2002

AbstractAberrations in the components of cell‐cycle checkpoints are a common feature of many tumours and several have been shown to have prognostic significance in colorectal cancer. In this study, seven components of cell‐cycle control [cyclin D1, retinoblastoma (pRb), p21, p27, p16, p53, and proliferating cell nuclear antigen (PCNA)] were examined in a large series of well‐characterized colorectal adenocarcinomas using immunohistochemistry to ascertain co‐regulation and influence on survival. The majority (92%) of the tumours had abnormal staining of ⩾2 cell‐cycle control factors. Expression of cyclin D1 protein was correlated with both p21 (p<0.001) and p27 (p=0.033), suggesting co‐regulation of these proteins in colorectal tumours. Only cyclin D1 (p=0.048) and p53 (p=0.025) were directly associated with PCNA levels, suggesting a more important role in the proliferative capacity of tumour cells. Significant associations between cell cycle‐related proteins and clinicopathological data were observed: cyclin D1 and p53 proteins were correlated with patient age (p=0.042 and p<0.001, respectively) and p53 (p=0.01) and p21 (p=0.024) proteins were associated with tumour site. Expression of cyclin D1 protein was the only protein examined that was related to improved outcome in these patients (p=0.0266), but itwas not an independent predictor of survival. These results suggest that loss of control of cell‐cycle checkpoints is a common occurrence in colorectal tumours and may be an important therapeutic target. Copyright © 2002 John Wiley & Sons, Ltd.
The Wnt pathway, epithelial–stromal interactions, and malignant progression in phyllodes tumours
Authors: Sawyer Elinor J. , Hanby Andrew M. , Rowan Andrew J. , Gillett Cheryl E. , Thomas Rachel E. , Poulsom Richard , Lakhani Sunil R. , Ellis Ian O. , Ellis Paul , Tomlinson Ian P. M. 
Published: October 2002

AbstractIn a previous study of phyllodes tumours, it has been shown that both the stroma and the epithelium can exhibit distinct molecular changes, suggesting that both are part of the neoplastic process. In view of this finding, it was decided to study stromal–epithelial interactions in these tumours by examining the Wnt–APC–β‐catenin pathway. β‐catenin and cyclin D1 immunohistochemistry was performed on 119 phyllodes tumours. Eighty‐six (72%) showed stromal nuclear β‐catenin localization and in 57% the staining was moderate or strong; however, of the eight malignant tumours in the series, seven showed absent or weak nuclear staining (p<0.025). In no tumour was nuclear β‐catenin staining seen in the epithelial component. Moderate or strong stromal cyclin D1 staining correlated with nuclear stromal β‐catenin staining (p<0.05). Forty‐five of the tumours, including two malignant lesions, were screened for β‐catenin exon 3 mutations using SSCP and sequencing, but none was found. Loss of heterozygosity (LOH) of the marker D5S346 was used to infer APC mutation, but only one (benign) tumour showed LOH. Wnt2 and Wnt5a mRNA was localized by in situ hybridization in 13 cases (three malignant) chosen to reflect the different β‐catenin staining patterns. There was an association between strong nuclear β‐catenin staining of stromal cells and epithelial Wnt5a expression (p<0.0015). These data suggest that stromal proliferation in benign phyllodes tumours relies on abnormalities in the Wnt pathway which result not from mutation, but from Wnt5a expression in the epithelium. In the progression to malignancy, the stromal proliferation appears to become independent of the Wnt pathway and, presumably, of the epithelial component of these tumours. Copyright © 2002 John Wiley & Sons, Ltd.
Malignancy‐associated allelic losses on the X‐chromosome in foregut but not in midgut endocrine tumours
Authors: Pizzi Silvia , D'Adda Tiziana , Azzoni Cinzia , Rindi Guido , Grigolato Piergiovanni , Pasquali Claudio , Corleto Vito D. , Delle Fave Gianfranco , Bordi Cesare 
Published: October 2002

AbstractInformation on genetic changes involved in the progression of gastroenteropancreatic (GEP) endocrine tumours is scanty. On the other hand, the identification of molecular markers of malignancy could be crucial for the prognostic evaluation of these neoplasms, which is hardly predictable on the basis of conventional histological criteria. An association of X‐chromosome deletions with malignancy has already been found in gastric endocrine tumours. To investigate this further, a comparative loss of heterozygosity (LOH) analysis was performed on 17 pancreatic endocrine tumours (PETs) and 17 intestinal (ten ileal, six appendiceal, and one rectal) carcinoids from female patients. The relationship of X‐chromosome LOH with the ploidy status of the neoplasms was also investigated. LOH was found in six of eight malignant PETs (60% of the informative markers), but was infrequent in the nine benign ones (4.5%). In contrast, although retention of heterozygosity was consistently observed in benign midgut tumours, LOH was infrequent in malignant carcinoids (15%). No correlation was found between LOH and the ploidy status. These results indicate an association between X‐chromosome LOH and malignancy in foregut endocrine tumours. The lack of such an association in midgut carcinoids suggests that different molecular mechanisms are involved in the progression of these two categories of endocrine neoplasms, which are otherwise considered to be closely related. These findings emphasize the need for further molecular studies on GEP endocrine tumours, carefully subdivided according to their anatomical site of origin. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of seven oestrogen receptor β antibodies for immunohistochemistry, western blotting, and flow cytometry in human breast tissue
Authors: Skliris G. P. , Parkes A. T. , Limer J. L. , Burdall S. E. , Carder P. J. , Speirs V. 
Published: October 2002

AbstractTwo oestrogen receptors, ERα and ERβ, exist. While much is known about ERα, the role of ERβ is still undefined, especially at the protein level. The aim of this study was to determine the utility of seven ERβ antibodies (14C8, 8D5, PAI313, PPG5/10, N19, 9.88, and D7N) raised against different domains of ERβ in three commonly used laboratory applications, namely immunohistochemistry, western blot, and flow cytometry, using human breast material. For immunohistochemical analysis of frozen material, PAI313 and D7N gave stronger and more specific signals than 14C8, 8D5, and PPG5/10. In paraffin sections, 14C8, closely followed by PPG5/10, gave by far the most superior nuclear immunoreactivity, compared with the other antibodies tested. In general, flow cytometry results mirrored the immunohistochemistry data for paraffin sections, with antibodies ranked 14C8>8D5≥PAI‐313>PPG5/10>D7N. For western blotting, 8D5 and D7N yielded the strongest and most consistent bands, with weaker bands seen with the others. It is concluded that ERβ protein can be detected using specific antibodies. However, there is considerable variation between the specificity and application of these antibodies, highlighting the fact that careful optimization is required when selecting an antibody for use in a particular laboratory technique. Copyright © 2002 John Wiley & Sons, Ltd.