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See detailDual analysis for finite element solutions of plate bending
Debongnie, Jean-François ULg; Nguyen-Xuan, Hung; Cung, N. H.

in Topping, B. H. V.; Montero, G.; Montenegro, R. (Eds.) Proceedings of the Eighth International Conference on Computational Structures Technology (2006, September)

This paper presents the application of the dual analysis concept to plate bending. In this method, a same problem is analyzed parallely by a displacement and an equilibrium model. The energetic distance ... [more ▼]

This paper presents the application of the dual analysis concept to plate bending. In this method, a same problem is analyzed parallely by a displacement and an equilibrium model. The energetic distance between these two models is the sum of both global errors and consequently, an upper bound of each of them. After an exposition of the two models, numerical examples are presented, which illustrate the high obtainable accuracy of the method. [less ▲]

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See detailDual analysis with general boundary conditions
Debongnie, Jean-François ULg; Zhong, H. G.; Beckers, Pierre ULg

in Computer Methods in Applied Mechanics & Engineering (1995), 122(1-2), 183-192

The dual analysis concept was introduced by Fraeijs de Veubeke [1] as a consequence of upper and lower bounds of the energy. As such bounds exist only in those cases where one type of condition is ... [more ▼]

The dual analysis concept was introduced by Fraeijs de Veubeke [1] as a consequence of upper and lower bounds of the energy. As such bounds exist only in those cases where one type of condition is homogeneous, it is commonly admitted that a dual error measure does not exist with general boundary conditions. This paper presents a re-examination of the dual error measure by a way which avoids any use of upper and lower bounds of the energy. It is found that such an error measure holds whatever the boundary conditions be. Furthermore, it is not necessary to obtain the approximate solutions by a Rayleigh-Ritz process, so that the second analysis, which seemed necessary in the original dual analysis concept, may be replaced by any admissible approximation. This implies the possibility of a dual error measure at a simple post-processor level. [less ▲]

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See detailDual anticancer drug/superparamagnetic iron oxide-loaded PLGA-based nanoparticles for cancer therapy and magnetic resonance imaging
Schleich, N.; Sibret, Pierre ULg; Danhier, P. et al

in International Journal of Pharmaceutics (2013), 447(1-2), 94-101

We developed dual paclitaxel (PTX)/superparamagnetic iron oxide (SPIO)-loaded PLGA-based nanoparticles for a theranostic purpose. Nanoparticles presented a spherical morphology and a size of 240 nm. The ... [more ▼]

We developed dual paclitaxel (PTX)/superparamagnetic iron oxide (SPIO)-loaded PLGA-based nanoparticles for a theranostic purpose. Nanoparticles presented a spherical morphology and a size of 240 nm. The PTX and iron loading were 1.84 ± 0.4 and 10.4 ± 1.93 mg/100 mg respectively. Relaxometry studies and phantom MRI demonstrated their efficacy as T2 contrast agent. Significant cellular uptake by CT26 cells of nanoparticles was shown by Prussian blue staining and fluorescent microscopy. While SPIO did not show any toxicity in CT-26 cells, PTX-loaded nanoparticles had a cytotoxic activity. PTX-loaded nanoparticle (5 mg/kg) with or without co-encapulated SPIO induced in vivo a regrowth delay of CT26 tumors. Together these multifunctional nanoparticles may be considered as future nanomedicine for simultaneous molecular imaging, drug delivery and real-time monitoring of therapeutic response. [less ▲]

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See detailDual approach for an accurate estimation of pull-in voltage
Rochus, Véronique ULg; Lemaire, Etienne ULg; Geuzaine, Christophe ULg

in Proceedings of the IVth European Conference on Computational Mechanics (ECCM 2010) (2010)

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See detailDual Approach for Electromechanical Coupling in MEMS
Rochus, Véronique ULg; Golinval, Jean-Claude ULg; Geuzaine, Christophe ULg

(2009)

In this paper we present an approach for the computation of coupled electromechanical problems in micro-electromechanical systems based on a vector potential formulation of the electrostatic problem. This ... [more ▼]

In this paper we present an approach for the computation of coupled electromechanical problems in micro-electromechanical systems based on a vector potential formulation of the electrostatic problem. This formulation is the dual of the scalar potential approach commonly used in the literature. We present an analytic derivation of the force computed using this dual method based on the virtual work principle, and compare the primal and dual approaches on the finite element solution of simple twodimensional test-cases. [less ▲]

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See detailDual approach using a variant perimeter constraint and efficient sub-iteration scheme for topology optimization
Zhang, Weihong; Duysinx, Pierre ULg

in Computers & Structures (2003), 81(22-23), 2173-2181

To prevent numerical instabilities associated with the mesh-dependence, checkerboards and grey regions in topology optimization, a variant perimeter-constrained version of the SIMP algorithm is proposed ... [more ▼]

To prevent numerical instabilities associated with the mesh-dependence, checkerboards and grey regions in topology optimization, a variant perimeter-constrained version of the SIMP algorithm is proposed using a smooth and quadratic function. In order to have an efficient implementation and to make sure the strict satisfaction of such an upper-bound perimeter constraint, a diagonal quadratic approximation of the perimeter constraint is used in the construction of each explicit optimization subproblem. The latter is then solved by a dual sub-iteration scheme. Numerical results show that the incorporation of such a sub-iteration scheme leads to a convergent solution without needs of move-limits or artificial control parameters. In addition to this, it is found that successive relaxations of the perimeter constraint by increasing the upper-bound tend to regularize the topology solution and result in a checkerboard free and satisfactory design solution without grey regions. [less ▲]

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See detailDual Citizenship and Home-country Voting
Lafleur, Jean-Michel ULg

Conference (2010, May 05)

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See detailDual effects of an extra disulfide bond on the activity and stability of a cold-adapted alpha-amylase
D'Amico, Salvino ULg; Gerday, Charles ULg; Feller, Georges ULg

in Journal of Biological Chemistry (2002), 277(48), 46110-46115

Chloride-dependent alpha-amylases constitute a well conserved family of enzymes thereby allowing investigation of the characteristics of each member to understand, for example, relevant properties ... [more ▼]

Chloride-dependent alpha-amylases constitute a well conserved family of enzymes thereby allowing investigation of the characteristics of each member to understand, for example, relevant properties required for environmental adaptation. In this context, we have constructed a double mutant (Q58C/A99C) of the cold-active and heat-labile alpha-amylase from the Antarctic bacterium Pseudoalteromonas haloplanktis, defined on the basis of its strong similarity with the mesophilic enzyme from pig pancreas. This mutant was characterized to understand the role of an extra disulfide bond specific to warm-blooded animals and located near the entrance of the catalytic cleft. We show that the catalytic parameters of the mutant are drastically modified and similar to those of the mesophilic enzyme. Calorimetric studies demonstrated that the mutant is globally stabilized (DeltaDeltaG = 1.87 kcal/mol at 20 degrees C) when compared with the wild-type enzyme, although the melting point (T-m) was not increased. Moreover, fluorescence quenching experiments indicate a more compact structure for the mutated a-amylase. However, the strain imposed on the active site architecture induces a 2-fold higher thermal inactivation rate at 45 degreesC as well as the appearance of a less stable calorimetric domain. It is concluded that stabilization by the extra disulfide bond arises from an enthalpy-entropy compensation effect favoring the enthalpic contribution. [less ▲]

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See detailDual energy X-ray absorptiometry-based assessment of male patients using standardized bone density values and a national reference database
Goemaere, S.; Vanderschueren, D.; Kaufman, J. M. et al

in Journal of Clinical Densitometry (2007), 10(1, JAN-MAR), 25-33

Dual energy X-ray absorptiometry (DXA) measurements from different manufacturers provide different bone mineral density (BMD) values and derived T-scores and Z-scores. These differences result partly from ... [more ▼]

Dual energy X-ray absorptiometry (DXA) measurements from different manufacturers provide different bone mineral density (BMD) values and derived T-scores and Z-scores. These differences result partly from technical differences in the algorithms for the determination of bone mineral content and bone area and partly from the use of different manufacturer-derived reference databases. The present study was to implement a uniforrn expression of BNID in all male patients by using standardized BMD (sBMD) values and referring to a newly established national male reference sample. In 8 bone densitometry centers throughout Belgium 229 young healthy men were measured on Hologic (Bedford, MA) or GE-Lunar (Madison, WI) bone densitometers. Quality control procedures were implemented and site cross-calibration performed using the European Spine Phantom. Absolute BMD values were converted to standardized values by validated formulas (sBMD). Clinically acceptable between-center differences were noted. No discrepancy was observed in terms of mean sBMD and standard deviations at the lumbar spine and proximal femur between the Belgian and the US reference populations. Region-specific sBMD thresholds for the diagnosis of male osteoporosis were calculated. The current data provide a basis to implement a nation-wide, uniform expression of BMD in male patients and allow harmonization of the BMD-based diagnosis and treatment of osteoporosis in men. [less ▲]

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See detailDual finite element formulations for the three-dimensional modeling of both inductive and capacitive effects in massive inductors
Dular, Patrick ULg; Kuo-Peng, Patrick

in IEEE Transactions on Magnetics (2006), 42(4), 743-746

Dual finite element formulations are developed for modeling both inductive and capacitive effects in massive inductors. Mixed finite elements are used to satisfy each chosen conformity level for the ... [more ▼]

Dual finite element formulations are developed for modeling both inductive and capacitive effects in massive inductors. Mixed finite elements are used to satisfy each chosen conformity level for the unknown fields and to naturally define the global quantities involved in the inductive and capacitive circuit relations, to be used in circuit coupling. The interest of satisfying conformity properties for the considered magnetic and electric coupled problems is shown and the related mathematical and discrete tools for any wished conformity level are developed. [less ▲]

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See detailDual finite element formulations taking eddy currents in lamination stacks into account
Dular, Patrick ULg; Gyselinck, J.; Geuzaine, Christophe ULg et al

in Proceedings of the 5th Brazilian Conference on Electromagnetics, CBMag 2002 (2002)

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See detailDual Formulations for Accurate Thin Shell Models in a Finite Element Subproblem Method
Dang, Quoc Vuong ULg; Dular, Patrick ULg; Vazquez Sabariego, Ruth ULg et al

in Proceeding of the 19th COMPUMAG Conference on the Computation of Electromagnetic Fields, 2013 (2013, April 01)

A subproblem finite with dual finite element magnetostatic and magnetodynamic formulations is developed for correcting the inaccuracies near edges and corners coming from thin shell models, that replace ... [more ▼]

A subproblem finite with dual finite element magnetostatic and magnetodynamic formulations is developed for correcting the inaccuracies near edges and corners coming from thin shell models, that replace thin volume regions by surfaces. The surface-to-volume correction problem is defined as one of the multiple subproblems applied to a complete problem, considering successive additions of inductors and magnetic or conducting regions, some of these being thin regions. Each SP requires a proper adapted mesh of its regions, which facilitates meshing and increases computational e ciency. [less ▲]

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See detailDual Formulations for Low Frequency Thin Conducting Magnetic Shell Modeling
Geuzaine, Christophe ULg; Dular, Patrick ULg; Klinkenberg, P. et al

in Proceedings of the 8th International IGTE Symposium on Numerical Field Calculation in Electrical Engineering (1998)

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See detailDual Formulations for the Modeling of Thin Conducting Magnetic Shells
Geuzaine, Christophe ULg; Dular, Patrick ULg; Legros, Willy ULg

in Procedings of the Eighth International Symposium on Numerical Field Calculation in Electrical Engineering (IGTE 1998) (1998)

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See detailDual Formulations for the Modeling of Thin Electromagnetic Shells using Edge Elements
Geuzaine, Christophe ULg; Dular, Patrick ULg; Legros, Willy ULg

in IEEE Transactions on Magnetics (2000), 36(4), 799-803

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See detailDual Formulations for the Modeling of Thin Electromagnetic Shells using Edge Elements
Geuzaine, Christophe ULg; Dular, Patrick ULg; Legros, Willy ULg

in Proceedings of the 12th COMPUMAG Conference on the Computation of Electromagnetic Fields (1999)

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See detailDual function of ERRalpha in breast cancer and bone metastasis formation: implication of VEGF and osteoprotegerin.
Fradet, Anais; Sorel, Helene; Bouazza, Lamia et al

in Cancer Research (2011), 71(17), 5728-38

Bone metastasis is a complication occurring in up to 70% of advanced breast cancer patients. The estrogen receptor-related receptor alpha (ERRalpha) has been implicated in breast cancer and bone ... [more ▼]

Bone metastasis is a complication occurring in up to 70% of advanced breast cancer patients. The estrogen receptor-related receptor alpha (ERRalpha) has been implicated in breast cancer and bone development, prompting us to examine whether ERRalpha may function in promoting the osteolytic growth of breast cancer cells in bone. In a mouse xenograft model of metastatic human breast cancer, overexpression of wild-type ERRalpha reduced metastasis, whereas overexpression of a dominant negative mutant promoted metastasis. Osteoclasts were directly affected and ERRalpha upregulated the osteoclastogenesis inhibitor, osteoprotegerin (OPG), providing a direct mechanistic basis for understanding how ERRalpha reduced breast cancer cell growth in bone. In contrast, ERRalpha overexpression increased breast cancer cell growth in the mammary gland. ERRalpha-overexpressing primary tumors were highly vascularized, consistent with an observed upregulation of angiogenic growth factor, the VEGF. In support of these findings, we documented that elevated expression of ERRalpha mRNA in breast carcinomas was associated with high expression of OPG and VEGF and with disease progression. In conclusion, our results show that ERRalpha plays a dual role in breast cancer progression in promoting the local growth of tumor cells, but decreasing metastatic growth of osteolytic lesions in bone. [less ▲]

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See detailDual Harmonic and Time Approaches for the Design of Microwave Devices
Meys, B.; Geuzaine, Christophe ULg; Henrotte, F. et al

in IEEE Transactions on Magnetics (1999), 35(3), 1829--1832

Detailed reference viewed: 7 (0 ULg)