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See detailMechanobiological modeling can explain orthodontic tooth movement: three case studies.
Van Schepdael, An ULg; Vander Sloten, J.; Geris, Liesbet ULg

in Journal of Biomechanics (2013), 46(3), 470-7

Progress in medicine and higher expectation of quality of life has led to a higher demand for several dental and medical treatments. This increases the occurrence of situations in which orthodontic ... [more ▼]

Progress in medicine and higher expectation of quality of life has led to a higher demand for several dental and medical treatments. This increases the occurrence of situations in which orthodontic treatment is complicated by pathological conditions, medical therapies and drugs. Together with experiments, computer models might lead to a better understanding of the effect of pathologies and medical treatment on tooth movement. This study uses a previously presented mechanobiological model of orthodontic tooth displacement to investigate the effect of pathologies and (medical) therapies on the result of orthodontic treatment by means of three clinically relevant case studies looking at the effect of estrogen deficiency, the effect of OPG injections and the influence of fluoride intake. When less estrogen was available, the model predicted bone loss and a rise in the number of osteoclasts present at the compression side, and a faster bone resorption. These effects were also observed experimentally. Experiments disagreed on the effect of estrogen deficiency on bone formation, while the mechanobiological model predicted very little difference between the pathological and the non-pathological case at formation sites. The model predicted a decrease in tooth movement after OPG injections or fluoride intake, which was also observed in experiments. Although more experiments and model analysis is needed to quantitatively validate the mechanobiological model used in this study, its ability to conceptually describe several pathological conditions is an important measure for its validity. [less ▲]

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See detailMechanobiology and cell tensegrity: the root of ethnic hair curling?
Pierard-Franchimont, Claudine; PAQUET, Philippe ULg; QUATRESOOZ, Pascale ULg et al

in Journal of Cosmetic Dermatology (2011), 10(2), 163-7

BACKGROUND: The hair shape, either straight, crimp, or curly, is basically under genetic influence. It is possibly altered by some drugs such as cytostatic agents. In addition, specific innate molecular ... [more ▼]

BACKGROUND: The hair shape, either straight, crimp, or curly, is basically under genetic influence. It is possibly altered by some drugs such as cytostatic agents. In addition, specific innate molecular characteristics are modulated by some cosmetic procedures to reshape the hair shafts. AIM: To revisit the possible implication of mechanobiology and cell tensegrity in shaping ethnic hair. MATERIALS AND METHODS: Optical and scanning electron microscopy of hairs. RESULTS: It is generally held that the cross-section shape of hair is related to differences in the global aspect of the hair shaft. A possible biologic link between these features may rely on shaping cell tensegrity at any portion of the hair shaft. Cell tensegrity encompasses all intrinsic and extrinsic forces responsible for the three-dimensional arrangement of intracellular macromolecules. CONCLUSION: We offer as a hypothesis that the hair shape in part depends on the organization of the cell proliferation in the hair matrix. This review gathers observations supporting the involvement of cell tensegrity in shaping the hair shaft. [less ▲]

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See detailMechanobiology and force transduction in scars developed in darker skin types.
Quatresooz, Pascale ULg; Hermanns, Jean-François ULg; Paquet, Philippe ULg et al

in Skin Research & Technology (2006), 12(4), 279-82

BACKGROUND: Scarring is a complex process involving many cell types, cytokines and biological pathways including mechanobiology. Some subtle mechanical properties of skin can be assessed by measuring the ... [more ▼]

BACKGROUND: Scarring is a complex process involving many cell types, cytokines and biological pathways including mechanobiology. Some subtle mechanical properties of skin can be assessed by measuring the speed of ultrasound shear wave propagation. The orientation of abnormal skin tension forces can be visualized, particularly in darker skin types, using dermoscopy showing distinct patterns of rete ridges' conformation. AIM: To assess some mechanobiological features of scars in darker skin types. PATIENTS AND METHODS: Large atrophic and hypertrophic surgical scars were examined on the trunk of 35 darker skin subjects. The surrounding skin was used as a comparator. Dermoscopic aspects were recorded. Resonance running time measurements (RRTM) were performed using a shear wave propagation device (Reviscometer). They were performed in four specific directions at given angles with regard to the long axis of the scar. The minimum, maximum and mean RRTM values were recorded at each site. RESULTS: Dermoscopy revealed patterns of melanin deposits in scars distinct from the normal honeycomb network seen in the surrounding skin. Hypertrophic scars showed a patchy pattern of large macular melanoderma dispersed in a lighter background. In these cases, low RRTM values were obtained with little variations according to the orientation of the measurements. By contrast, atrophic scars showed a streaky laddering melanotic pattern under dermoscopy. Higher RRTM values were often obtained, particularly in the transversal direction of the scars. Mechanical anisotropy was greater in the atrophic scars compared with the normal skin. DISCUSSION: Darker skin types represent a model for visualizing the main orientation of the epidermal rete ridges. A correlation was found between the pattern of melanized rete ridges of scars and the main orientation of the intrinsic forces in the skin. [less ▲]

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See detailMechanobiology of bone regeneration and bone adaptation to achieve stable long-term fixation of endosseous implants
Geris, Liesbet ULg; Van Oosterwyck, Hans; Duyck, Joke et al

in Zeman, M. E.; Cerrolaza, M. (Eds.) Computational Modeling of Tissue Surgery (2005)

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See detailThe mechanobiology of tissue differentiation around immediately loaded implants: a bone chamber experiment
Geris, Liesbet ULg; Van Oosterwyck, Hans; Duyck, Joke et al

in Proceedings of the 14th conference of the European Society of Biomechanics (2004)

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See detailA mechanobioregulatory model for the study of bone fracture healing
Geris, Liesbet ULg; Gerisch, A.; Weiner, R. et al

in Proceedings of the European Conference on Mathematical and Theoretical Biology (2008)

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See detailMechanochemical Study of a Single Polypeptide Molecule: Force-Induced Conformational Transition
Willet, Nicolas ULg; Hinterdorfer, Peter; Lecommandoux, Sébastien et al

Conference (2011, June)

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See detailMechanochemical Study of Conformational Transitions in a Single Synthetic Peptide Chain
Willet, Nicolas ULg; Hinterdorfer, Peter; Lecommandoux, Sébastien et al

Poster (2012, June 05)

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in ... [more ▼]

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in detail by atomic force microscopy (AFM) at the single-molecule level. Synthetic copolymers containing a polypeptide block were prepared by N-carboxyanhydride amino acid ring-opening polymerization. The polymer chains were grafted as a dilute brush onto gold surfaces via disulfide end-groups. Their mechanochemical behavior was then studied by AFM single-molecule force spectroscopy (SMFS). The investigated polypeptide blocks were based on poly(L-glutamic acid), which undergoes a transition from alpha-helix to random coil. This can be induced by external stimuli (pH, ionic strength, temperature) or simply by applying a force. We were able to study the mechanically driven unfolding of the peptide by stretching-release cycles of the biomacromolecule. Stretching the helical peptide resulted in original features in the force-distance traces. Plateaus that are specific for the helical conformation were detected, quantified and discussed. Pulling-relaxing SMFS experiments eventually led to a better understanding of the force induced unfolding of an alpha-helix and the reversibility of the phenomenon. [less ▲]

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See detailMechanochemistry of a single polypeptide molecule: Study of force-induced conformational transitions
Willet, Nicolas ULg; Hinterdorfer, Peter; Lecommandoux, Sébastien et al

Conference (2011, August)

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in ... [more ▼]

The aim of this study is to investigate the mechanochemical behavior of homopolypeptides able to change their conformation is a stimuli-responsive way. The peptidic secondary structures were studied in detail by atomic force microscopy (AFM) at the single-molecule level. Synthetic copolymers containing a polypeptide block were prepared by N-carboxyanhydride amino acid ring-opening polymerization. The polymer chains were grafted as a dilute brush onto gold surfaces via disulfide end-groups. Their mechanochemical behavior was then studied by AFM single-molecule force spectroscopy (SMFS). The investigated polypeptide blocks were based on poly(L-glutamic acid), which undergoes a transition from alpha-helix to random coil. This can be induced by external stimuli (pH, ionic strength, temperature) or simply by applying a force. We were able to study the mechanically driven unfolding of the peptide by stretching-release cycles of the biomacromolecule. Stretching the helical peptide resulted in original features in the force-distance traces. Plateaus that are specific for the helical conformation were detected, quantified and discussed. Pulling-relaxing SMFS experiments eventually led to a better understanding of the force induced unfolding of a alpha-helix and the reversibility of the phenomenon. [less ▲]

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See detailMechanochemistry: targeted delivery of single molecules
Duwez, Anne-Sophie ULg; Cuenot, Stéphane; Jérôme, Christine ULg et al

in Nature Nanotechnology (2006), 1

The use of scanning probe microscopy-based techniques to manipulate single molecules(1) and deliver them in a precisely controlled manner to a specific target represents a significant nanotechnological ... [more ▼]

The use of scanning probe microscopy-based techniques to manipulate single molecules(1) and deliver them in a precisely controlled manner to a specific target represents a significant nanotechnological challenge(2,3). The ultimate physical limit in the design and fabrication of organic surfaces can be reached using this approach. Here we show that the atomic force microscope (AFM), which has been used extensively to investigate the stretching of individual molecules(4-12), can deliver and immobilize single molecules, one at a time, on a surface. Reactive polymer molecules, attached at one end to an AFM tip, are brought into contact with a modified silicon substrate to which they become linked by a chemical reaction. When the AFM tip is pulled away from the surface, the resulting mechanical force causes the weakest bond - the one between the tip and polymer - to break. This process transfers the polymer molecule to the substrate where it can be modified by further chemical reactions. [less ▲]

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See detailMechanoreceptors in the anterior horn of the equine medial meniscus: an immunohistochemical approach
Nemery, Elodie ULg; Gabriel, Annick ULg; Grulke, Sigrid ULg et al

in Anatomia, Histologia, Embryologia (2016), 45

Lameness due to stifle and especially meniscal lesions is frequent in equine species. In humans, mechanoreceptors involved in proprioceptive function are well studied. Given the high incidence of meniscal ... [more ▼]

Lameness due to stifle and especially meniscal lesions is frequent in equine species. In humans, mechanoreceptors involved in proprioceptive function are well studied. Given the high incidence of meniscal injuries in horses, and the lack of information concerning them in equine menisci, our objective was to study these corpuscles in six healthy anterior horns of the equine medial meniscus, which is the most common localisation reported for equine meniscal injuries. Immunohistochemical stainings were performed using antibodies against high molecular weight neurofilaments and glial fibrillary acidic proteins. From a purely fundamental point of view, our work highlights for the first time the presence of Ruffini, Pacini and Golgi corpuscles in equine meniscus. They were found, isolated or in clusters and always located at the vicinity of blood vessels, at the level of the anterior horn of the equine medial meniscus. This morphological approach could serve as a basis for clinical studies, to evaluate the impact of these corpuscles on the poor sportive prognosis in equine meniscal tears. [less ▲]

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See detailMechanoreceptors in the anterior horn of the equine medial meniscus: an immunohistochemical approach.
Nemery, Elodie ULg; Gabriel, Annick ULg; Grulke, Sigrid ULg et al

Poster (2014)

Mechanoreceptors are “encapsulated sensory end-organs” involved in proprioceptive function. Given the high incidence of meniscal injuries in horses, the clinical interest in these mechanoreceptors ... [more ▼]

Mechanoreceptors are “encapsulated sensory end-organs” involved in proprioceptive function. Given the high incidence of meniscal injuries in horses, the clinical interest in these mechanoreceptors, particularly in the meniscus, and the lack of information concerning them in equine menisci, our objective was to study these corpuscles in the anterior horn of the equine medial meniscus, which is the most common localization reported for equine meniscal injuries. An immunohistochemical approach to detect Schwann cells and nerve fibres allowed us to localize and identify these corpuscles within the meniscus. Three types of mechanoreceptors were identified and localized between the abaxial quarter and the abaxial third of the meniscus: the Ruffini, Pacini and Golgi corpuscles. In conclusion, from a purely fundamental point of view, our work highlights for the first time the presence of MCR at the level of the anterior horn of the equine medial meniscus and proposes a classification based on specific immunocytochemical techniques. This morphological approach could serve as a basis for clinical studies, in order to evaluate the impact of these corpuscles on the poor sportive prognosis in equine meniscal tears. [less ▲]

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See detailThe mechanosensitivity of cells in joint tissues: Role in the pathogenesis of joint diseases
Sanchez, Christelle ULg; Mathy, Marianne ULg; Henrotin, Yves ULg

in Kamkin, André; Kiseleva, Irina (Eds.) Mechanosensitivity and Mechanotransduction (2011)

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See detailMechanotransductive cascade of Myo-II-dependent mesoderm and endoderm invaginations in embryo gastrulation
Mitrossilis, Démosthène; Röper, Jens-Christian; Roy, Damien Le et al

in Nature Communications (2017), 8

Animal development consists of a cascade of tissue differentiation and shape change. Associated mechanical signals regulate tissue differentiation. Here we demonstrate that endogenous mechanical cues also ... [more ▼]

Animal development consists of a cascade of tissue differentiation and shape change. Associated mechanical signals regulate tissue differentiation. Here we demonstrate that endogenous mechanical cues also trigger biochemical pathways, generating the active morphogenetic movements shaping animal development through a mechanotransductive cascade of Myo-II medio-apical stabilization. To mimic physiological tissue deformation with a cell scale resolution, liposomes containing magnetic nanoparticles are injected into embryonic epithelia and submitted to time-variable forces generated by a linear array of micrometric soft magnets. Periodic magnetically induced deformations quantitatively phenocopy the soft mechanical endogenous snail-dependent apex pulsations, rescue the medio-apical accumulation of Rok, Myo-II and subsequent mesoderm invagination lacking in sna mutants, in a Fog-dependent mechanotransductive process. Mesoderm invagination then activates Myo-II apical accumulation, in a similar Fog-dependent mechanotransductive process, which in turn initiates endoderm invagination. This reveals the existence of a highly dynamic self-inductive cascade of mesoderm and endoderm invaginations, regulated by mechano-induced medio-apical stabilization of Myo-II. [less ▲]

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See detailMeckel's diverticulum as a cause of colic: 2 cases with different morphological features
Verwilghen, Denis ULg; Van Galen, Gaby ULg; Busoni, Valeria ULg et al

in Tijdschrift voor Diergeneeskunde (2010), 135(11), 452-455

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See detailMECOSIG adapted to the design of distributed GIS
Pasquasy, Fabien; Laplanche, François; Sainte, Jean-Christophe et al

in Lecture Notes in Computer Science (2005), 3762

For more than ten years MECOSIG has been used as a method for GIS design and implementation in various national and international projects achieved in our laboratory. During a decade, the method has been ... [more ▼]

For more than ten years MECOSIG has been used as a method for GIS design and implementation in various national and international projects achieved in our laboratory. During a decade, the method has been progressively improved and extended without modification of its basic principles. However the emergence of distributed GIS, implying several organizations capable to play various roles, requires the reappraisal of the methodology. New concerns are identified and a collection of new tools must be deployed. Taking the most of various recent researches completed for public authorities in Belgium, this paper presents some significant adaptations of the original MECOSIG method in order to cope with a distributed GIS environment. [less ▲]

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See detailMECOSIG Adapted to the Design of Distributed GIS
Pasquasy, Fabien; Laplanche, François; Sainte, Jean-Christophe et al

in OTM 2005 Workshops (2005)

Detailed reference viewed: 29 (5 ULg)