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Peer Reviewed
See detailMorphological and mechanical characterization of porous structures with micro-CT
Kerckhofs, Greet ULg; Wevers, Martine; Schrooten, Jan

in Abstract book SkyScan User Meeting 2005 (2005)

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Peer Reviewed
See detailMorphological and mechanical characterization of Ti6Al4V scaffolds produced with selective laser melting
Van Bael, Simon; Kerckhofs, Greet ULg; Moesen, Maarten et al

in Proc. ECCOMAS - International Conference on Tissue Engineering 2009. . 2009, Bártolo, P. (Eds.) (2009)

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See detailMorphological and Mechanical Quantification of Porous Structures by Means of Micro-CT (Morfologische en mechanische kwantificatie van poreuze structuren met behulp van micro-CT)
Kerckhofs, Greet ULg

Doctoral thesis (2009)

Suitable characterization techniques for porous structures are required to (i) understand and to be able to simulate, via finite elements (FE), the structure-properties relationships and (ii) understand ... [more ▼]

Suitable characterization techniques for porous structures are required to (i) understand and to be able to simulate, via finite elements (FE), the structure-properties relationships and (ii) understand the relationship between the morphology and mechanical behaviour on one hand, and the failure mechanisms on the other hand. X-ray microfocus computed tomography (micro-CT) offers a solution as it provides a means to acquire a complete 3D set of images of the structure visualizing the internal architecture at the microscopic level in a non-destructive way. Additionally, the micro-CT images enable subsequent image analysis, resulting in an extensive 3D quantitative description of the morphology that cannot be obtained by other methods. But, one has to be aware of the fact that micro-CT images are inherently subjected to artefacts and that the image quality and accuracy depend on multiple factors. For example, the acquisition settings (target material, tube voltage and filter material) influence the X-ray spectra and hence also the image quality. The spatial resolution strongly influences the accuracy of the micro-CT images and as a result also the morphological analysis. Closely related to the latter, the material architecture has a significant influence on the micro-CT image accuracy, which is also affected by the material type. In a first part of this study, systematic, fast and user-independent protocols have been developed both for acquisition parameter optimization and for image accuracy validation, and the influence of the different factors mentioned above on the image accuracy has been investigated. As a result, when applying these protocols, the micro-CT user should know, for different material types and architectures, what the capabilities and limitations of micro-CT are for morphological assessment of porous structures. In a second part, this knowledge has been applied and the use of micro-CT has been expanded to the mechanical characterization of porous structures by combining micro-CT imaging and 3D image analysis with in-situ mechanical loading, FE analysis and local strain mapping as this combination allows to (i) provide in-situ and experimentally the mechanical properties, (ii) link the mechanical properties to the morphology, (iii) investigate the morphological changes under compressive loading, (iv) feed and validate a FE model which can be applied for the prediction of the mechanical properties that cannot readily be determined experimentally and (v) predict the failure modes by using experimental local strain mapping. [less ▲]

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See detailMorphological and Molecular Characterization of Lymnaeid Snails and Their Potential Role in Transmission of Fasciola spp. in Vietnam
Bui Thi, Dung ULg; Pham Ngoc, Doanh; Dang Tat, The et al

in Korean Journal of Parasitology (2013), 51(6), 657-662

Freshwater snails of the family Lymnaeidae play an important role in the transmission of fascioliasis worldwide. In Vietnam, 2 common lymnaeid species, Lymnaea swinhoei and Lymnaea viridis, can be ... [more ▼]

Freshwater snails of the family Lymnaeidae play an important role in the transmission of fascioliasis worldwide. In Vietnam, 2 common lymnaeid species, Lymnaea swinhoei and Lymnaea viridis, can be recognized on the basis of morphology, and a third species, Lymnaea sp., is known to exist. Recent studies have raised controversy about their role in transmission of Fasciola spp. because of confusion in identification of the snail hosts. The aim of this study is, therefore, to clarify the identities of lymnaeid snails in Vietnam by a combination of morphological and molecular approaches. The molecular analyses using the second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA clearly showed that lymnaeids in Vietnam include 3 species, Austropeplea viridis (morphologically identified as L. viridis), Radix auricularia (morphologically identified as L. swinhoei) and Radix rubiginosa (morphologically identified as Lymnaea sp.). R. rubiginosa is a new record for Vietnam. Among them, only A. viridis was found to be infected with Fasciola spp. These results provide a new insight into lymnaeid snails in Vietnam. Identification of lymnaeid snails in Vietnam and their role in the liver fluke transmission should be further investigated. [less ▲]

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See detailMorphological and molecular characterization of planktonic cyanobacteria from Belgium and Luxembourg
Willame, R.; Boutte, C.; Grubisic, Stana ULg et al

in Journal of Phycology (2006), 42(6), 1312-1332

For the first time in Belgium and Luxembourg, the diversity and taxonomy of 95 cyanobacterial strains isolated from freshwater blooms were assessed by the comparison of phenotypes and partial 16S rRNA ... [more ▼]

For the first time in Belgium and Luxembourg, the diversity and taxonomy of 95 cyanobacterial strains isolated from freshwater blooms were assessed by the comparison of phenotypes and partial 16S rRNA gene sequences. The results showed the high diversity of nanoplanktonic, picoplanktonic, and benthic-periphytic cyanobacteria accompanying the main bloom-forming taxa. Indeed, besides 15 morphotypes of bloom-forming taxa, seven non-bloom-forming planktonic morphotypes and 11 morphotypes from benthic-periphytic taxa were isolated in culture from the plankton samples of 35 water bodies. The bloom-forming strains belonged to the genera Microcystis, Woronichinia, Planktothrix, Anabaena, and Aphanizomenon, whereas the other strains isolated from the same samples were assigned to the nanoplanktonic Aphanocapsa, Aphanothece, Snowella, and Pseudanabaena; to the picoplanktonic Cyanobium; and to the benthic periphytic Geitlerinema, Komvophoron, Leptolyngbya, Lyngbya, Phormidium, Calothrix, Nostoc, and Trichormus. The results supported both the polyphyletism of genera such as Aphanocapsa, Aphanothece, Leptolyngbya, Geitlerinema, Anabaena, and Aphanizomenon as well as the validity of genera such as Microcystis, Planktothrix, and Pseudanabaena with gas vesicles and cells constricted at the cross wall. The results obtained showed the close relationship between Snowella and Woronichinia for which very few sequences exist. The first sequence of Komvophoron appeared poorly related to other available cyanobacterial sequences. Although in a few cases a good agreement existed between phenotypic and genotypic features, there was generally a discrepancy. Strains with identical morphotypes show small differences in the 16S rRNA sequences, which might be related to the different chemical properties of their habitats. The results showed the importance of the polyphasic approach in order to improve the taxonomy of cyanobacteria. [less ▲]

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See detailMorphological and molecular diversity within Algerian cowpea (Vigna unguiculata (L.) Walp.) landraces
Ghalmi, Naima; Malice, Marie ULg; jacquemin, Jean-Marie et al

in Genetic Resources and Crop Evolution (2010), (57), 371-386

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See detailMorphological and morphometric analyses of the suspensory ligament in Standardbreds
Shikh Al Sook, Mohamad Khir ULg; Antoine, Nadine ULg; Piret, Joëlle ULg et al

Poster (2012, October)

Ultrasound techniques allow examination of some parts of the suspensory ligament (SL) but "anomalies" are regularly observed. Their significance is not known. Few studies have described the relationship ... [more ▼]

Ultrasound techniques allow examination of some parts of the suspensory ligament (SL) but "anomalies" are regularly observed. Their significance is not known. Few studies have described the relationship between ultrasonographic appearance and the exact morphology in histological sections. The aim of this study is to develop good techniques for cutting, staining, and showing the variation in the tissue composition within the SL. The SLs from the right limbs of 11 horses were collected. Samples were taken from cross-sections at six levels of the SL and they were embedded in paraffin or in Tissue-Tek®. Most of the paraffin sections were shredded. By using the cryosection technique, some freezing artifacts (holes) appeared. Therefore, a technique of freezing with cryoprotection was carried out, which produced the best results. Hematoxylin-phloxine-saffron gives a good contrast of colors between the tissues observed allowing the use of an image analysis program. The percentage of each tissue within the SL for each section and for six levels of the ligament was calculated. Results were analyzed by SAS software. The muscle tissue (PMT) and adipose tissue (PAT) decreased significantly (p < 0.0001), whereas the connective tissue (PCT) increased significantly (p < 0.0001) with age and when descending from the proximal to the distal level of the SL. The PMT was significantly higher (p < 0.0001) in females than males, while the PCT was significantly higher (p < 0.0001) in males than females. The PAT was significantly higher (p = 0.0278) in hindlimbs than in forelimbs. [less ▲]

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See detailMorphological and opto-electrical properties of solution deposited Platinum counter electrode for low cost dye sensitized solar cells
Thalluri, Venkata Visveswara Gopala Kris ULg; Décultot, Marc ULg; Henrist, Catherine ULg et al

in Physical Chemistry Chemical Physics [=PCCP] (2013), 15

Although Platinum (Pt) is a rare and very expensive material, Pt counter electrodes are still very commonly used for reaching high efficiencies in dye-sensitized solar cells (DSCs). The use of alternative ... [more ▼]

Although Platinum (Pt) is a rare and very expensive material, Pt counter electrodes are still very commonly used for reaching high efficiencies in dye-sensitized solar cells (DSCs). The use of alternative cheaper catalyst materials did not yet yield to equivalent efficiencies. In this work, we tried to understand how to reduce the amount of deposited Pt-material and simultaneously to deliver higher DSC performances. We systematically compared the properties of Pt-counter electrodes prepared by simple solution deposition methods such as spray-coating, dip-coating, brushing with reference to the Pt-electrodes prepared by sputtering onto fluorine doped-tin oxides (FTOs). The morphological and structural characterizations of the deposited Pt-layers were performed by atomic force microscopy (AFM) and scanning electron microscope (SEM). The composition of Pt-material was quantified by using SEM electron dispersive x-ray (EDX) mapping measurements are further compared with optical transmission measurements. Also contact angle and sheet resistance measurements were performed. By taking Pt-layers composition, morphology and structural factors into account 9.16% efficient N3 dye based DSCs were assembled. The DSCs were subjected to various opto-electrical characterization techniques like current-voltage (I-V), external quantum efficiency (EQE), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and transient photo voltage (TPV) measurements. The obtained experimental data suggest that the Pt counter electrodes prepared by solution deposition methods can also reach to high DSC device performances with a consumption of very less amount of Pt material compared with sputtered Pt-layers. This process also proves that higher DSC performances are not limited to the usage of sputtered Pt-layer as counter electrode. [less ▲]

Detailed reference viewed: 73 (19 ULg)
See detailMorphological Biomarkers
Javaux, Emmanuelle ULg

in Gargaud et al (Ed.) Encyclopedia of Astrobiology (2011)

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See detailMorphological changes of the nucleolus during oogenesis in oviparous teleost fish, Barbus barbus (L.).
Thiry, Marc ULg; Poncin, Pascal ULg

in Journal of Structural Biology (2005), 152(1), 1-13

In fishes, like in amphibians, it is well established that variations in rRNA activity occur during oogenesis. Contrary to amphibians, however, little is known about the ultrastructural changes of the ... [more ▼]

In fishes, like in amphibians, it is well established that variations in rRNA activity occur during oogenesis. Contrary to amphibians, however, little is known about the ultrastructural changes of the nucleolus during fish oogenesis. Evolution of the nucleolus has been followed during oogenesis in the teleost fish Barbus barbus (L.) using light and transmission electron microscopies. We show that the behaviour of the nucleolus during B. barbus oogenesis resembles that reported in amphibians but also presents several peculiarities. The most striking feature is the marked vacuolization of nucleoli occurs at the beginning of the growth during previtellogenesis. The results obtained by means of the in situ terminal deoxynucleotidyl transferase-immunogold method for detecting DNA seem further to indicate that the chromatin cap becomes integrated into developing nucleoli during previtellogenesis and then segregate at the periphery of nucleoli at the end of glycoproteinic vitellogenesis. Our study also shows that the nucleoli of germ cells, like that of follicle cells, are devoid of fibrillar centre but comprise a fibrillar and a granular component whatever the oogenetic stage. Ultrastructural detection of DNA and nucleolar proteins (AgNOR proteins, fibrillarin, and pp135) supports further the view that the Barbus nucleolus is a bipartite structure. [less ▲]

Detailed reference viewed: 44 (6 ULg)
Peer Reviewed
See detailMorphological Changes of Thymus in Retrovirus-Induced Murine Acquired Immunodeficiency Syndrome (Maids)
de Leval, Laurence ULg; Deprez, Manuel ULg; Colombi, S. et al

in Pathology - Research & Practice (1995), 191(6), 506-12

The possible contribution of the thymus in the setting of acquired immunodeficiencies is still questioned. Here we report some new findings regarding a potential involvement of the thymus in mice infected ... [more ▼]

The possible contribution of the thymus in the setting of acquired immunodeficiencies is still questioned. Here we report some new findings regarding a potential involvement of the thymus in mice infected with RadLV-Rs, a viral mixture inducing murine acquired immunodeficiency syndrome (MAIDS). Thymi were sequentially removed, weighted and morphologically analyzed at different time intervals post-infection. Infection with RadLV-Rs led to a decrease in thymus weight mostly apparent from the fourth week. The first changes were seen at the third week as perivascular clusters of B-cells at the cortico-medullary junction. The ensuing process of atrophy mainly involved the cortex, while a mixed population of large T- and B-cells filled the medulla. These observations are discussed with regard to the pathological changes occurring in other lymphoid and non-lymphoid organs, in the context of the lymphoproliferation and immunodeficiency characterizing the disease, and by comparison with other models of retrovirus-induced immunodeficiencies. [less ▲]

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See detailMorphological Characterization of a Novel Scaffold for Anterior Cruciate Ligament Tissue Engineering
Laurent, Cédric ULg; GANGHOFFER, J-F; BABIN, J et al

in Journal of Biomechanical Engineering (2011), 133

Tissue engineering offers an interesting alternative to current anterior cruciate ligament (ACL) surgeries. Indeed, a tissue-engineered solution could ideally overcome the long- term complications due to ... [more ▼]

Tissue engineering offers an interesting alternative to current anterior cruciate ligament (ACL) surgeries. Indeed, a tissue-engineered solution could ideally overcome the long- term complications due to actual ACL reconstruction by being gradually replaced by biological tissue. Key requirements concerning the ideal scaffold for ligament tissue en- gineering are numerous and concern its mechanical properties, biochemical nature, and morphology. This study is aimed at predicting the morphology of a novel scaffold for ligament tissue engineering, based on multilayer braided biodegradable copoly(lactic acid-co-(e-caprolactone)) (PLCL) fibers The process used to create the scaffold is briefly presented, and the degradations of the material before and after the scaffold processing are compared. The process offers varying parameters, such as the number of layers in the scaffold, the pitch length of the braid, and the fibers’ diameter. The prediction of the mor- phology in terms of pore size distribution and pores interconnectivity as a function of these parameters is performed numerically using an original method based on a virtual scaffold. The virtual scaffold geometry and the prediction of pore size distribution are evaluated by comparison with experimental results. The presented process permits crea- tion of a tailorable scaffold for ligament tissue engineering using basic equipment and from minimum amounts of raw material. The virtual scaffold geometry closely mimics the geometry of real scaffolds, and the prediction of the pore size distribution is found to be in good accordance with measurements on real scaffolds. The scaffold offers an intercon- nected network of pores the sizes of which are adjustable by playing on the process pa- rameters and are able to match the ideal pore size reported for tissue ingrowth. The adjustability of the presented scaffold could permit its application in both classical ACL reconstructions and anatomical double-bundle reconstructions. The precise knowledge of the scaffold morphology using the virtual scaffold will be useful to interpret the activity of cells once it will be seeded into the scaffold. An interesting perspective of the present work is to perform a similar study aiming at predicting the mechanical response of the scaffold according to the same process parameters, by implanting the virtual scaffold into a finite element algorithm. [less ▲]

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Peer Reviewed
See detailMorphological comparison of the buccal apparatus in two bivalve commensal Carapidae
Parmentier, Eric ULg; Castro-Aguirre, Jose Luis; Vandewalle, Pierre ULg

in American Zoologist (2000)

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See detailMorphological comparison of the buccal apparatus in two bivalve commensal Teleostei : Encheliophis dubius and Onuxodon fowleri (Carapidae, Ophidiiformes)
Parmentier, Eric ULg; Castro-Aguirre, J. L.; Vandewalle, Pierre ULg

in Zoomorphology (2000), 120

Onuxodon fowleri and Encheliophis dubius are two Carapidae species that live in bivalve hosts and, their diet is made of the same type of prey. The aim of this study is to compare their cephalic ... [more ▼]

Onuxodon fowleri and Encheliophis dubius are two Carapidae species that live in bivalve hosts and, their diet is made of the same type of prey. The aim of this study is to compare their cephalic morphology to see whether 1) the head anatomy of both species is related to the constraints of their way of life, and 2) there are difference between these species and commensal carapids that shelter in other invertebrates. The components of their skeletons and muscles are similar, but differ in size and are arranged differently. In O. fowleri, the buccal cavity is smaller than in E. dubius, the jaws (bearing very large anterior teeth) are larger, the quadrato-mandibular joint lies further to the rear, the fibres of muscle bundles A3a, A2a and A2b are more vertical and insert higher on the neurocranium. The buccal system of O. fowleri appears better suited for ingesting food by biting and grasping. That of E. dubius seems better adapted to a feeding mechanism where sucking would have a more important role. The E. dubius head morphology is more similar to the cephalic anatomy of non-bivalve commensal species than to O. fowleri features. Diet constraints may have greater influence than the different host constraints on the head construction. A simulated backward rotation of the posterior part of the E. dubius suspensorium around the posterior joint between the hyomandibular and the neurocranium brings the jaws and the cheeks to coincide with those of O. fowleri. This model could be indicative of how structure modifications and their influences on annex pieces could in part have a role in the biodiversity. [less ▲]

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See detailMorphological comparison of the buccal apparatus in two bivavle commensal Carapidae
Parmentier, Eric ULg; Castro-Aguirre; Vandewalle, Pierre ULg

in American Zoologist (1999), 39(5),

Detailed reference viewed: 5 (1 ULg)
Peer Reviewed
See detailMorphological decomposition in visual word recognition in French beginning readers
Quemart, Pauline ULg; Casalis, Séverine; Mathiot, Emmanuelle

Poster (2007, July)

Detailed reference viewed: 5 (0 ULg)