bluuebunny/crossref_metadata_2025_split huggingface dataset:
An augmented Lagrangian approach to essential boundary conditions in meshless methods
Authors: Ventura G. 
Published: October 2002

AbstractThe problem of boundary conditions enforcement in meshless methods has been solved in the literature by several approaches. In the present paper, the moving least‐squares (MLS) approximation is introduced in the total potential energy functional for the elastic solid problem and an augmented Lagrangian term is added to satisfy essential boundary conditions. The method can be easily extended to any kind of constraint for the approximation variables. The solution is found by iterating alternatively on approximation variables and on Lagrange multipliers. The advantages of the proposed formulation are: (a) the ability to deal with the same approach with any constraint type; (b) the number of the variables is not increased by the Lagrange multipliers; (c) the Hessian of the functional w.r.t. the approximation variables is banded, well conditioned and strictly positive definite and (d) the cost of the augmented Lagrangian iteration is a very small fraction of the global computing time. Therefore, the augmented Lagrangian element‐free (ALEF) approach represents an attractive and very efficient numerical tool, not only for the boundary conditions enforcement, but also for the solution of interface and non‐linear problems. Copyright © 2001 John Wiley & Sons, Ltd.
On configurational forces in the context of the finite element method
Authors: Mueller R. , Kolling S. , Gross D. 
Published: October 2002

AbstractThe theory of configurational forces is briefly recast, together with the underlying balance laws. It is shown, that in the case of a homogeneous body without body forces the additional balance laws are identically satisfied if the standard force balance holds. In approximate solutions, for example obtained by finite elements, the equilibrium is not satisfied exactly, thus configurational forces occur on discretization nodes. An implementation of the configurational force balance into the finite element scheme is presented. The use of configurational forces is discussed with three main aspects. It is demonstrated how configurational forces can be used to check and to improve the finite element solution. Examples from fracture mechanics and problems with material inhomogeneities are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Time‐discretized variational formulation of non‐smooth frictional contact
Authors: Pandolfi A. , Kane C. , Marsden J. E. , Ortiz M. 
Published: October 2002

AbstractThe present work extends the non‐smooth contact class of algorithms introduced by Kane et al. to the case of friction. The formulation specifically addresses contact geometries, e.g. involving multiple collisions between tightly packed non‐smooth bodies, for which neither normals nor gap functions can be properly defined. A key aspect of the approach is that the incremental displacements follow from a minimum principle. The objective function comprises terms which account for inertia, strain energy, contact, friction and external forcing. The Euler–Lagrange equations corresponding to this extended variational principle are shown to be consistent with the equations of motion of solids in frictional contact. In addition to its value as a basis for formulating numerical algorithms, the variational framework offers theoretical advantages as regards the selection of trajectories in cases of non‐uniqueness. We present numerical and analytical examples which demonstrate the good momentum and energy conservation characteristics of the numerical algorithms, as well as the ability of the approach to account for stick and slip conditions. Copyright © 2001 John Wiley & Sons, Ltd.
A control volume capacitance method for solidification modelling with mass transport
Authors: Davey K. , Rodriguez N. J. 
Published: October 2002

AbstractCapacitance methods are popular methods used for solidification modelling. Unfortunately, they suffer from a major drawback in that energy is not correctly transported through elements and so provides a source of inaccuracy. This paper is concerned with the development and application of a control volume capacitance method (CVCM) to problems where mass transport and solidification are combined. The approach adopted is founded on theory that describes energy transfer through a control volume (CV) moving relative to the transporting mass. An equivalent governing partial differential equation is established, which is designed to be transformable into a finite element system that is commonly used to model transient heat‐conduction problems. This approach circumvents the need to use the methods of Bubnov–Galerkin and Petrov–Galerkin and thus eliminates many of the stability problems associated with these approaches. An integration scheme is described that accurately caters for enthalpy fluxes generated by mass transport. Shrinkage effects are neglected in this paper as all the problems considered involve magnitudes of velocity that make this assumption reasonable. The CV approach is tested against known analytical solutions and is shown to be accurate, stable and computationally competitive. Copyright © 2002 John Wiley & Sons, Ltd.
A precise computation of stress intensity factor on the front of a convex planar crack
Authors: Ascenzi Oscar , Pareschi Lorenzo , Segala Fausto 
Published: October 2002

AbstractIn this paper, we consider a general integral expression for mode I stress intensity factor along the fronts of convex planar cracks. For this integral approximation, we develop a simple numerical quadrature formula on every convex set Ω which allows a precise estimation of the error. This permits the use of extrapolation techniques for the accurate computation of the integral. Copyright © 2002 John Wiley & Sons, Ltd.
New soybean oil‐Styrene‐Divinylbenzene thermosetting copolymers—IV. Good damping properties
Authors: Li Fengkui , Larock Richard C. 
Published: October 2002

AbstractNew polymeric materials have been prepared by the cationic copolymerization of regular soybean oil, low saturation soybean oil, i.e. LoSatSoy oil, or conjugated LoSatSoy oil with styrene and divinylbenzene, norbornadiene or dicyclopentadiene initiated by boron trifluoride diethyl etherate (BF
3·OEt
2) or related modified initiators. The effects of the stoichiometry, the type of soybean oil and the alkene comonomer on the damping behavior of the resulting polymers have been investigated. The damping properties have been quantitatively evaluated by the loss tangent maximum (tan δ)
max, ­the temperature range ΔT for efficient damping (tan δ > 0.3), and the integrals of the linear tan δ v. temperature curves (tan δ area, TA). These bulk materials are composed primarily of soybean oil‐styrene‐divinylbenzene random copolymers with considerable variability in the backbone compositions. The good damping properties of the soybean oil polymers are presumably determined by the presence of fatty acid ester side groups directly attached to the polymer backbone and the segmental heterogeneities resulting from crosslinking. In general, crosslinking reduces the (tan δ)
max and the TA values, but broadens the region of efficient damping (ΔT). Soybean oil polymeric materials with appropriate compositions and crosslink densities are capable of efficiently damping over a temperature region in excess of 110 °C and provide noise and vibration attenuation over broad temperature and frequency ranges. Copyright © 2002 John Wiley & Sons, Ltd.
Comparative studies of osteoblast and fibroblast type I collagen in a patient with osteogenesis imperfecta type IV
Authors: Galicka Anna , Wolczynski Slawomir , Gindzienski Andrzej 
Published: October 2002

AbstractThe expression of type I collagen has been compared in fibroblast and osteoblast cultures of a patient with moderately severe osteogenesis imperfecta (OI) type IV, with respect to control cells. Electrophoretic analysis of type I collagen showed that both OI osteoblasts and fibroblasts synthesized normal chains and chains with delayed migration. However, the osteoblasts contained a higher proportion of abnormal chains than fibroblasts from the proband. Pulse‐chase experiments showed that the trimers containing abnormal chains were cleared more rapidly from osteoblasts than fibroblasts. Moreover, the collagen secreted by OI osteoblasts had thermal stability 1°C higher than collagen secreted by OI fibroblasts. These results suggest that the abnormal collagen in osteoblasts may be more resistant to intra‐ and extracellular degradation and may thus have better survival than in fibroblasts. This finding could have implications for understanding the clinical phenotype of OI. Copyright © 2001 John Wiley & Sons, Ltd.
Telemicroscopy by the Internet revisited
Authors: Brauchli K. , Christen H. , Haroske G. , Meyer W. , Kunze K. D. , Oberholzer M. 
Published: October 2002

AbstractThis paper reports a fundamentally new concept for internet‐based telemicroscopy. By separating a telemicroscopy application into three tasks – microscope control program, external server, and client application – it is possible to establish a telemicroscopy session between two arbitrary end points on the Internet even if both of the end points are secured by firewall (microscope and client application). The advantages of such a distributed system, compared with the classical point‐to‐point systems, are discussed. The telemicroscopy system is combined with a telepathology database, which is capable of automatically recording telemicroscopy sessions, allowing a convenient combination of interactive remote microscopy and store and forward telepathology. In addition to remote primary diagnosis, it is easily possible to discuss difficult cases within dedicated user groups, no matter whether images originate from a telemicroscopy session, or are manually entered into the database. Copyright © 2001 John Wiley & Sons, Ltd.
Lumican expression in alpha cells of islets in pancreas and pancreatic cancer cells
Authors: Ping Lu Yue , Ishiwata Toshiyuki , Asano Goro 
Published: October 2002

AbstractLumican is a member of a small leucine‐rich proteoglycan family, members of which play an important role in cell migration and proliferation during embryonic development, tissue repair, and tumour growth. Lumican is reported to be overexpressed during the wound healing process in the cornea and in human breast cancer tissues, but its expression and localization in normal pancreas and pancreatic cancer tissues are not known. The present study aimed to clarify the expression of lumican protein and its mRNA in human pancreatic cancer cell lines and their localization in normal and cancerous human pancreatic tissues. Reverse transcription‐polymerase chain reaction (RT‐PCR) and western blot analysis revealed lumican mRNA and its protein expression in PK‐8 and MIA‐PaCa‐2 human pancreatic cancer cells. The tumour lumican had non‐ or poorly sulphated polylactosamine side‐chains rather than highly sulphated keratan sulphate chains. Immunoreactivity of the lumican protein was localized in alpha cells of islets and stromal tissues of a normal pancreas. In pancreatic cancer tissues, the lumican protein was strongly localized in cancer cells, and in acinar and islet cells in chronic pancreatitis‐like lesions adjacent to the cancer cells. It was also localized in fibroblasts and collagen fibres close to cancer cells. Lumican mRNA was expressed in cancer cells, in acinar and islet cells in chronic pancreatitis‐like lesions, and in stromal fibroblasts in the pancreatic cancer tissues. This is the first report that lumican is synthesized in endocrine and cancer cells. Lumican protein may play a role in the maintenance of islet cell function in normal pancreas and the lumican protein synthesized by cancer cells, acinar and islet cells, and stromal fibroblasts may play a role in the growth of human pancreatic cancer cells. Copyright © 2001 John Wiley & Sons, Ltd.
Genetic pathways in the evolution of breast ductal carcinoma in situ
Authors: Farabegoli Fulvia , Champeme Marie‐Helene , Bieche Ivan , Santini Donatella , Ceccarelli Claudio , Derenzini Massimo , Lidereau Rosette 
Published: October 2002

AbstractThe patterns of allelic loss in 28 cases of pure ductal carcinoma in situ (DCIS) and 25 cases of DCIS associated with invasive ductal carcinoma (IDC) were compared, in order to define whether pure DCIS represented an earlier stage than DCIS associated with IDC in the progression ofbreast carcinoma. To this aim, the polymerase chain reaction (PCR) was performed on microdissected normal and neoplastic breast tissue, formalin‐fixed and paraffin‐embedded. Fifteen microsatellite markers were examined, on chromosomes 1p, 3p, 7q, 11q, 12p, 13q, 16q and 17q, mostly focused on regions altered in breast cancer. Loss of heterozygosity (LOH) was greater in pure DCIS than in the DCIS component associated with IDC for 11 out of 15 markers. The difference was statistically significant for D13S260 and D17S800 (p=0.008 and p=0.01, respectively). DCIS associated with IDC showed a lesser degree of alteration than the synchronous IDC component for ten out of 15 markers. In contrast, LOH at D11S1816 and D16S318 was lower in pure DCIS than in DCIS associated with IDC and even greater in the IDC component. These results confirm that DCIS is a possible but not an obligate precursor of invasive breast cancer and suggest that pure DCIS and DCIS associated with IDC may be genetically distinct. The evolution from DCIS to IDC may follow multiple pathways and not a linear model. Copyright © 2002 John Wiley & Sons, Ltd.
Identification of loci associated with putative recurrence genes in transitional cell carcinoma of the urinary bladder
Authors: Edwards Joanne , Duncan Pamela , Going James J. , Watters Amanda D. , Grigor Kenneth M. , Bartlett John M. S. 
Published: October 2002

AbstractFollowing an earlier study linking monosomy 9 with recurrence of transitional cell carcinomas (TCCs) of the urinary bladder, 109 primary and recurrent TCCs (from 47 patients) were examined to explore genetic alterations at chromosome 9 associated with recurrence. Patient DNA was microdissected and extracted from archival tissue sections and analysed for loss of heterozygosity (LOH) at three regions on chromosome 9 where tumour suppressor genes (TSGs) are known to reside (INK 4A, DBC1, and TSC1). Patients were categorized into two groups, non‐recurrent TCC (NR, n=18) and recurrent TCC (REC, n=29). It was noted that 12% of NR tumours, compared with 54% of REC primary tumours (p=0.01), had LOH at all informative markers spanning the TSC1 region. The risk of recurrence was significantly higher in patients with deleted TSC1 than in those who retained the TSC1 region (p=0.035). Levels of LOH at DBC1 or INK 4A were not significantly different in NR tumours than in REC primary tumours and recurrence‐free survival was not affected by loss of either of these genes. Loss of all informative markers spanning chromosome 9 was observed in 0% of NR tumours compared with 25% of REC primary tumours (p=0.04). The probability of recurrence was also significantly increased in patients who had LOH at all informative markers spanning chromosome 9 (p=0.016), confirming earlier fluorescence in situ hybridization results. This study provides further evidence that recurrence in bladder cancer is a distinct event, with underlying molecular causes. It also identifies the TSC1 locus as a candidate for a TSG, which drives recurrence in a proportion of TCC patients. Loss of all informative markers, including those residing in the TSC1 region, spanning chromosome 9 was also linked to recurrence. Copyright © 2002 John Wiley & Sons, Ltd.
Expression of mucins (MUC1, MUC2, MUC5AC, and MUC6) and type 1 Lewis antigens in cases with and without Helicobacter pylori colonization in metaplastic glands of the human stomach
Authors: Teixeira Ana , David Leonor , Reis Celso A. , Costa Julia , Sobrinho‐Simões Manuel 
Published: October 2002

AbstractHelicobacter pylori (H. pylori) causes gastritis and intestinal metaplasia (IM) that may evolve to gastric carcinoma. Paradoxically, IM leads to clearing of H. pylori, except for some cases in which it persists in damaging the mucosa. The objective of this study was to compare the profile of mucins and type 1 Lewis antigens in IM cases with and without H. pylori. Gastric biopsies (n=32) were double‐stained using immunohistochemistry (MUC1, MUC2, MUC5AC, MUC6, Lea, sialyl‐Lea, and Leb) and histochemistry for H. pylori. H. pylori was observed in association with IM in 4 of 22 biopsies with IM (complete IM – 6; incomplete IM – 16). The four biopsies with IM and H. pylori displayed a particular pattern of incomplete IM: expression of MUC1 and MUC5AC and little/no expression of MUC2. The 18 biopsies with IM and without H. pylori had high levels of MUC2 expression, regardless of the IM type. The pattern of expression of type 1 Lewis antigens was similar in IM, regardless of the presence or absence of H. pylori. It is concluded that H. pylori is able to colonize incomplete IM whenever it contains foci expressing MUC1 and MUC5AC and no MUC2, independently from Lea, sialyl‐Lea and Leb. The results suggest, furthermore, that MUC2 expression affects the ability of H. pylori to colonize IM areas, regardless of the levels of expression of MUC1 and MUC5AC. Copyright © 2002 John Wiley & Sons, Ltd.
A possible role for complement in the pathogenesis of chronic chagasic cardiomyopathy
Authors: Demarchi Aiello Vera , Martins Reis Márcia , Alberto Benvenuti Luiz , de Lourdes Higuchi Maria , Antonio Franchini Ramires José , Halperin José A. 
Published: October 2002

AbstractThe membrane attack complex (MAC) of complement participates in several inflammatory and proliferative processes by releasing pro‐inflammatory cytokines and growth factors from target cells. Chronic Chagasic cardiomyopathy (CCH) is a parasitic dilated cardiopathy, characterized by severe fibrosis and inflammation, which differs from idiopathic dilated cardiomyopathy (DCM). Trypanosoma cruzi, the pathogenic organism of CCH, is a strong complement activator and can also induce alternative pathway activation by mammalian cells. This study explored whether the myocardium in CCH patients has increased MAC deposition, an expression of complement activation, compared to DCM patients. MAC was semi‐quantified in endomyocardial human samples (29 CCH subjects, 18 DCM subjects, and four controls) by immunohistochemistry. MAC was present in the sarcolemma of 38% of CCH, 5.5% of DCM (p<0.02), and 0% of controls, and in interstitial inflammatory cells of CCH. No difference was observed in the expression of the complement regulatory protein CD59, indicating that increased MAC deposition is likely to be the result of complement activation rather than decreased protection. It is proposed that the increased MAC deposition found in CCH, but not in DCM or controls, may help to explain the diffuse myocardial fibrosis and inflammation characteristic of the disease. Copyright © 2002 John Wiley & Sons, Ltd.
Lung epithelial stem cells
Authors: Otto W. R. 
Published: October 2002

AbstractThis review concentrates on recent evidence about lung stem cell origins and plasticity. The range of potential cells which can repopulate the injured lung, classically the basal and mucous secretory cells of the trachea, the Clara cells of the bronchiole, and the type II pneumocyte of the alveolus, has been extended to include the mucus‐gland duct cells of the trachea and bronchus. Some evidence suggests that there are variant Clara cells that lack cytochrome P‐450 and so are spared toxic activation of xenobiotics, and may aid bronchiolar repopulation after injury, such as with naphthalene. There may even be involvement of the neuroepithelial bodies or cells in this, though the evidence is not yet conclusive. The search for a resident pulmonary multipotent cell for repopulating any lung epithelium has not yet been successful. The picture remains similar to earlier conclusions, in that thelocalstem or precursor cell is the most likely to contribute to local needs in times of tissue damage. There remains a major challenge for lung cancer treatment, where high‐dose chemo‐ or radio‐therapy may be hoped to promote the seeding and repair of lung parenchyma by circulating bone marrow stem cells, as seen in liver models. Patient survival rates do not yet suggest that this occurs to any great extent, but this remains to be shown formally. The effects of prior fibrosis and tumour necrosis are probably confounding factors in this lack of rescue. Copyright © 2002 John Wiley & Sons, Ltd.
Chromosome 14q LOH in localized clear cell renal cell carcinoma
Authors: Mitsumori Kenji , Kittleson John M. , Itoh Noriyuki , Delahunt Brett , Heathcott Rosemary W. , Stewart John H. , McCredie Margaret R. E. , Reeve Anthony E. 
Published: October 2002

AbstractThe progression of a malignant tumour is understood to be the result of the accumulation of multiple genetic aberrations. As up to 14% of organ‐confined renal cell carcinomas will recur after surgery, tumour clones with metastatic potential must already be present in some of these localized tumours. The association of 14q LOH with high‐grade tumours and advanced tumour stage suggests an important role for the gene in tumour progression. Chromosome 14q LOH has been analysed in microdissected specimens from 130 organ‐confined (UICC TNM stage 1 and 2) clear cell renal cell carcinomas using three microsatellite markers (D14S588, D14S617, GATA136B01). Tumours were classified as 14q LOH or not on the basis of LOH at one or more of the markers. The allelic imbalance ratio was used to determine both LOH and LOH proportion and the association between LOH and mortality, tumour size, histological grade and growth kinetics, measured by quantification of nucleolar organizer regions, was analysed. 14q LOH was present in 35.4% of informative cases at marker D14S588, 24.4% at D14S617, 36.4% at GATA136B01 and 39.5% for any one of the three markers. The mean 14q LOH proportion was 0.24 (range 0.009–0.80). LOH proportion correlated significantly with tumour size, AgNOR score and histological grade. It was also significantly associated with disease‐specific mortality; (hazard ratio 1.22; 95% CI 1.02–1.45; p = 0.039). LOH proportion did not remain significant after adjusting for tumour size (hazard ratio 0.98; 95% CI 0.76–1.27; p = 0.90). These results indicate that the proportion of cells with 14q LOH in the tumour is associated with tumour aggressiveness; while this is not an independent predictor of survival, it may have some utility as a marker of latent metastatic potential. Copyright © 2002 John Wiley & Sons, Ltd.