S.Yu. Reutskiy¹

CMC-Computers, Materials & Continua, Vol.2, No.3, pp. 177-188, 2005, DOI:10.3970/cmc.2005.002.177

Abstract In this paper a new meshless method for eigenproblems with Laplace and biharmonic operators in simply and multiply connected domains is presented. The solution of an eigenvalue problem is reduced to a sequence of inhomogeneous problems with the differential operator studied. These problems are solved using the method of fundamental solutions. The method presented shows a high precision in simply and multiply connected domains. The results of the numerical experiments justifying the method are presented. More >

N. Ramakrishnan¹, P. Rama Rao²

CMC-Computers, Materials & Continua, Vol.2, No.3, pp. 163-176, 2005, DOI:10.3970/cmc.2005.002.163

Abstract Ductile fracture is initiated by void nucleation at a characteristic distance (I_c) from the crack tip and propagated by void growth followed by coalescence with the tip. The earlier concepts expressed I_c in terms of grain size or inter-particle distance because grain and particle boundaries form potential sites for void nucleation. However, Srinivas et al. (1994) observed nucleation of such voids even inside the crack tip grains in a nominally particle free Armco iron. In an attempt to achieve a unified understanding of these observations, typical crack-tip blunting prior to ductile fracture in a standard C(T) specimen… More >

Y. Tomita ¹, M. Uchida ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.3, pp. 239-248, 2005, DOI:10.3970/cmes.2005.010.239

Abstract In this study, we clarified the micro- to mesoscopic deformation behavior of a semicrystalline polymer by employing a large-deformation finite element homogenization method. The crystalline plasticity theory with a penalty method for the inextensibility of the chain direction and the nonaffine molecular chain network theory were applied for the representation of the deformation behavior of the crystalline and amorphous phases, respectively, in the composite microstructure of the semicrystalline polymer. The 3D structure of lamellae in the spherulite of high-density polyethylene was modeled, and the tensile and compressive deformation behaviors were investigated. A series of computational More >

M. Akamatsu¹, K. Nakane², N. Ohno^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.3, pp. 217-228, 2005, DOI:10.3970/cmes.2005.010.217

Abstract In this study, a fully implicit integration scheme is developed for a nonisothermal viscoplastic, nonlinear kinematic hardening model. Nonlinear dynamic recovery in addition to strain hardening is assumed for the evolution of multiple back stresses so that ratcheting and mean-stress relaxation can be properly simulated. Temperature dependence of back stress evolution is also taken into account in the constitutive model. By discretizing a set of such advanced constitutive relations using the backward Euler method, a tensor equation is derived and linearized to iteratively achieve the implicit integration of constitutive variables. The fully implicit integration scheme More >

Zhenyu Xue¹, Ashkan Vaziri¹, John W. Hutchinson¹

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.1, pp. 79-96, 2005, DOI:10.3970/cmes.2005.010.079

Abstract A constitutive model for the elastic-plastic behavior of plastically compressible orthotropic materials is proposed based on an ellipsoidal yield surface with evolving ellipticity to accommodate non-uniform hardening or softening associated with stressing in different directions. The model incorporates rate-dependence arising from material rate-dependence and micro-inertial effects. The basic inputs are the stress-strain responses under the six fundamental stress histories in the orthotropic axes. Special limits of the model include classical isotropic hardening theory, the Hill model for incompressible orthotropic solids, and the Deshpande-Fleck model for highly porous isotropic foam metals. A primary motivation is application… More >

Mahmoud Huleihel^1,4, Alaa Amash^1,3, Olga Sapir^2,3, Ester Maor⁴, Sharon Levy^1,3, Miriam Katz^2,3, Doron Dukler^2,4, Lesly Myatt⁵, Gershon Holcberg^2,3

European Cytokine Network, Vol.15, No.1, pp. 30-36, 2004

Abstract The aim of the study was to investigate the stimulatory effect of lipopolysaccharide (LPS) on IL-1α production in different compartments of term and preterm placental tissues. Homogenates from amnion, chorion, and from fetal (subchorionic placental tissues, maternal decidua, and mid-placental tissue before and after perfusion of isolated placental cotyledons of 5 term placentas and 4 placentas obtained after preterm birth (28-34 W of gestation) were examined. Isolated placental cotyledons were dually perfused LPS (100 ng/kg perfused placental tissue) was perfused into the maternal side during 10 hours. Homogenates of the samples were examined by ELISA… More >

Horst Rieth¹, Maik Mörmann¹, Adriana J. F. Luty^1,2, Constance A. Assohou-Luty¹, Maria Roupelieva¹, Peter G. Kremsner^1,2, Dieter Kube^1,3

European Cytokine Network, Vol.15, No.2, pp. 153-158, 2004

Abstract Interleukin-10 (IL-10) is an important multifunctional immunmodulator. There is evidence that IL-10 secretion is associated with certain genetic elements of the proximal IL-10 gene 5’-flanking region. The allelic and genotypic comparison of IL-10 expression by lipopolysaccharide (LPS)- stimulated leukocytes (PBMC) with a recently discovered distal “indel” DNA-sequence variation at – 7400 bp revealed significant inter-individual differences in the IL-10 in vitro production capacity. Homozygotes lacking the three base pairs “GGA” (– 7400del) at this gene locus are characterised by high expression of IL-10 with a median of 1690pg/ml (P ≤ 0.009). The allelic comparison supports More >

Isabelle Cognet¹, Florence Guilhot¹, Sylvie Chevalier², Angélique Guay-Giroux¹, Alexandra Bert¹, Greg C. A. Elson³, Hugues Gascan², Jean-François Gauchat¹

European Cytokine Network, Vol.15, No.3, pp. 255-262, 2004

Abstract Ciliary neurotrophic factor (CNTF) is a neuroprotective cytokine initially identified in chick embryo. It has been evaluated for the treatment of neurodegenerative diseases. CNTF also acts on non-neuronal cells such as oligodendrocytes, astrocytes, adipocytes and skeletal muscles cells. CNTF has regulatory effects on body weight and is currently in clinical trial for the treatment of diabetes and obesity. CNTF mediates its function by activating a tripartite receptor comprising the CNTF receptor α chain (CNTFRα), the leukemia inhibitory factor receptor β chain (LIFRβ) and gp130. Human, rat and chicken CNTF have been expressed as recombinant proteins,… More >

George Fildissis, Kyriaki Venetsanou, Pavlos Myrianthefs, Stylianos Karatzas, Vasilios Zidianakis, George Baltopoulos

European Cytokine Network, Vol.15, No.3, pp. 217-221, 2004

Abstract Hyperbaric oxygen (HBO) is a therapeutic intervention with applications in a large variety of diseases, including traumatic injuries and acute or chronic infections. The presence of pro-inflammatory cytokines regulates certain factors including adhesion molecules, which play a significant role in HBO effects.
We have investigated the effect of HBO on pro-inflammatory cytokine release [tumor necrosis factor-α (TNF-α), interleukin 6 and 8 (IL-6 and IL-8)], and the regulation of adhesion molecules [soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular adhesion molecule (sVCAM)] after lipopolysaccharide (LPS) stimulation in 16 healthy individuals, originating from an urban area. A total… More >

Claudio Pérez¹, Fermín E. González^1,2, Violeta Pavez³, Aida V. Araya⁴, Adam Aguirre¹, Andrea Cruzat^1,6, Juan Contreras-Levicoy^1,6, Andrés Dotte^1,6, Octavio Aravena¹, Lorena Salazar¹, Diego Catalán¹, Jimena Cuenca¹, Arturo Ferreira¹, Irene Schiattino⁵, Juan C. Aguillón¹

European Cytokine Network, Vol.15, No.4, pp. 364-370, 2004

Abstract Several single-nucleotide polymorphisms (SNPs) have been identified in the TNF-α gene promoter. The transition G→A at position –308 generates the TNF-α1 (G/G) and TNF-α2 (G/A or A/A) alleles, where the polymorphic TNF-α2 allele is associated with a high, in vitro TNF-α expression and an increased susceptibility to diverse illnesses. Here we study the association of the –308 TNF-α SNP with the susceptibility for developing aggressive periodontitis (AP), AP combined with type 1 diabetes mellitus (DM) and DM. We also explore the TNF-α capability expression and the presence of the –308 polymorphism. For this purpose we More >