Phylogeographic footprints of the Strait of Gibraltar and Quaternary climatic fluctuations in the western Mediterranean: a case study with the greater white-toothed shrew Crocidura russula (Mammalia: Soricidae); ; Libois, Roland et alin Molecular Ecology (2005), 14 We used mitochondrial cyt b sequences to investigate the phylogenetic relationships of Crocidura russula (sensu lato) populations across the Strait of Gibraltar, western Europe, Maghreb, and the ... [more ▼] We used mitochondrial cyt b sequences to investigate the phylogenetic relationships of Crocidura russula (sensu lato) populations across the Strait of Gibraltar, western Europe, Maghreb, and the Mediterranean and Atlantic islands. This revealed very low genetic divergence between European and Moroccan populations. The application of a molecular clock previously calibrated for shrews suggested that the separation of European from Moroccan lineages occurred less than 60000 BP, which is at least 5 million years (Myr) after the reopening of the Strait of Gibraltar. This means that an overwater dispersal event was responsible for the observed phylogeographical structure. In contrast, genetic analyses revealed that Moroccan populations were highly distinct from Tunisian ones. According to the molecular clock, these populations separated about 2.2 million years ago (Ma), a time marked by sharp alternations of dry and humid climates in the Maghreb. The populations of the Mediterranean islands Ibiza, Pantellaria, and Sardinian were founded from Tunisian populations by overwater dispersal. In conclusion, overwater dispersal across the Strait of Gibraltar, probably assisted by humans, is possible for small terrestrial vertebrates. Moreover, as in Europe, Quaternary climatic fluctuations had a major effect on the phylogeographical structure of the Maghreb biota. [less ▲] Detailed reference viewed: 11 (1 ULg) Phylogeographic history of the yellow-necked fieldmouse (Apodemus flavicollis) in Europe and in the Near and Middle East.Michaux, Johan ; Libois, Roland ; et alin Molecular Phylogenetics & Evolution (2004), 32(3), 788-98 The exact location of glacial refugia and the patterns of postglacial range expansion of European mammals are not yet completely elucidated. Therefore, further detailed studies covering a large part of ... [more ▼] The exact location of glacial refugia and the patterns of postglacial range expansion of European mammals are not yet completely elucidated. Therefore, further detailed studies covering a large part of the Western Palearctic region are still needed. In this order, we sequenced 972 bp of the mitochondrial DNA cytochrome b (mtDNA cyt b) from 124 yellow-necked fieldmice (Apodemus flavicollis) collected from 53 European localities. The aims of the study were to answer the following questions: Did the Mediterranean peninsulas act as the main refuge for yellow-necked fieldmouse or did the species also survive in more easterly refugia (the Caucasus or the southern Ural) and in Central Europe? What is the role of Turkey and Near East regions as Quaternary glacial refuges for this species and as a source for postglacial recolonisers of the Western Palearctic region? The results provide a clear picture of the impact of the quaternary glaciations on the genetic and geographic structure of the fieldmouse. This species survived the ice ages in two main refuges, the first one in the Italo-Balkan region; the second one in Turkey and the Near East regions. It is from the Balkan refuge that it recolonised all European regions at the end of the last glaciation. The Turkish and Near East populations are distinct from the European ones and they did not recolonise the Palearctic region probably because: (i) they were blocked by the Black Sea and the Caucasus, (ii) the long term presence of fieldmice populations in the Balkans prevented their expansion. These are genetically differentiated from the European and Russian ones and could be described as a particular subspecies. This result emphasises the importance of Turkey and the Near and Middle East regions as a refuge for Palearctic mammals. [less ▲] Detailed reference viewed: 16 (3 ULg) Phylogeographical analysis of bovine herpesvirus 4: demonstration that inter strain recombination events took place after acquisition of the bo17 gene from an ancestor of the african buffaloDewals, Benjamin G ; ; et alPoster (2005, March) Recently, our phylogenetic study revealed that the Bovine herpesvirus 4 (BoHV 4) Bo17 gene has been acquired from an ancestor of the African buffalo around 1.5 million years ago, implying that cattle ... [more ▼] Recently, our phylogenetic study revealed that the Bovine herpesvirus 4 (BoHV 4) Bo17 gene has been acquired from an ancestor of the African buffalo around 1.5 million years ago, implying that cattle subsequently acquired BoHV 4 by cross species transmission (Markine-Goriaynoff et al., 2003, 77:1784-1792). In the present study, we pursued our investigation on the origin and the evolution of BoHV 4. Firstly, with the goal in mind to further precise the origin of the Bo17 gene, the C2GnT M gene sequence was determined for each subspecies of African buffalo and for three types of Asian buffalo. Phylogenetic analyses of these new sequences further supported our conclusion that the Bo17 gene has been acquired from an ancestor of the African buffalo, possibly of the Syncerus caffer caffer subspecies from East-Africa origin. Secondly, to investigate the phylogeographical relationships among BoHV-4 strains isolated from four different continents, phylogenetic analyses were performed based on six different regions distributed throughout the genome. Analyses of these regions revealed a clear correlation between the phylogenetic relationships among BoHV-4 strains and their geographical origin, leading to the concept of BoHV-4 geographical clades. These analyses also demonstrated that since the acquisition of the Bo17 gene, recombination events occurred at different time in the past between ancestors of actual geographical clades. These recombinations provided an opportunity to learn how after acquisition of the Bo17 gene in Africa around 1.5 million years ago, BoHV-4 has spread to the world to form phylogenetically related geographical clades. [less ▲] Detailed reference viewed: 8 (1 ULg) Phylogéographie du complexe d'espèces Brassica oleraceaAigoin, Delphine ![]() Master of advanced studies dissertation (2005) The aim of this work is to clarify the genetic relationship between the species of the complex Brassica sect. oleracea and to suggest a historical scenario of cabbage domestication. We collected 79 ... [more ▼] The aim of this work is to clarify the genetic relationship between the species of the complex Brassica sect. oleracea and to suggest a historical scenario of cabbage domestication. We collected 79 accessions, corresponding to 2 to 5 individus for each of the 11 taxons of this complex. Three types of molecular markers were studied on these individuals : two nuclear genes (sequencing of Adh and G3pdh genes), for microsatellite loci, and AFLP markers. Only the first two types of markers were used for phylogenetic reconstructions. Overall there is little consistency among markers and among studies. However a few solid results can be outlined, such as 1/ the grouping of endemic species from Sicilia (B. rupestris, B. villosa, B. macrocarpa), 2/ the grouping of cultivated accesions with the taxon B. oleracea, suggesting a unique domestication event. Considerations from the various phylogenetic reconstructions, from morphological data, and from historical records, suggest that such domestication event first occured in the mediterranean islands, and that the presently «wild» populations of the atlantic coast were in fact probably produced from these domesticated populations. [less ▲] Detailed reference viewed: 98 (4 ULg) Phylogéographie mitochondriale du mulot sylvestre (Apodemus sylvaticus) dans la région paléarctique occidentale; ; et al in Biosystema, Systématique et biogéographie (2002), 20 We have sequenced 965 base pairs of the mitochondrial DNA cytochrome b from 102 woodmice (Apodemus sylvaticus) samples collected from 40 European localities. The aims of the study were to answer the ... [more ▼] We have sequenced 965 base pairs of the mitochondrial DNA cytochrome b from 102 woodmice (Apodemus sylvaticus) samples collected from 40 European localities. The aims of the study were to answer the following questions: i) Did the Mediterranean peninsulas play a role as a refuge for small mammals? ii) Is the genetic variability of a small mammal like A. sylvaticus higher in the Mediterranean regions as compared with northern Europe? iii)Is it possible to find patterns of postglacial colonisation of Europe other than those presently recognised ? Sequence data were analysed using Distance and Maximum Parsimony phylogenetic reconstruction methods. A minimum spanning network was also calculated. Population genetic structure was determined by analysis of molecular variance (AMOVA). A "mismatch distribution" analysis was also performed to estimate the patterns of expansion. The results provide a clear picture of the impact of Quaternary glaciations on the genetic and geographic structure of the woodmouse. Analyses indicate a higher genetic variability for the woodmouse in the Mediterranean peninsulas as compared to northern Europe and the role of these peninsulas as refuge regions for small mammals. A new pattern of postglacial colonisation is also proposed where the Iberian and southern France refuge populations colonised almost all the European regions. The Sicilian population appears to be highly differentiated and highly variable. This result emphasises the importance of this island as a "hot spot" for the intraspecific genetic diversity of the woodmouse. Finally, populations of this species in North Africa originated from south-western Europe and are probably the result of a recent anthropogenic introduction. [less ▲] Detailed reference viewed: 18 (2 ULg) Phylogeography and evolutionary history of Leopoldamys neilli, a Murinae rodent endemic to limestone karsts, in ThailandLatinne, Alice ; ; et alConference (2012, May 15) Limestone karsts are highly threatened biodiversity hotspots supporting high levels of endemic species. Karsts are patchy distributed within Southeast Asia and their isolation from one another give them ... [more ▼] Limestone karsts are highly threatened biodiversity hotspots supporting high levels of endemic species. Karsts are patchy distributed within Southeast Asia and their isolation from one another give them the features of “islands on the continent” and has important consequences for the genetic structure of endemic taxa. In present study, we have studied the phylogeography of Neill’s Rat Leopoldamys neilli, a threatened Murinae rodent species endemic to limestone karsts of Thailand, on the basis of two mitochondrial markers, two nuclear fragments, as well as twelve microsatellite loci. Our study gave evidence of a complex and strong geographic structure of the genetic diversity for L. neilli. Several highly differentiated genetic lineages were observed throughout Thailand. These results suggest a severe fragmentation of L. neilli’s populations, correlated to the fragmented distribution of its habitat and highlight its high endemicity to limestone karsts. The evolutionary history of L. neilli was investigated using Approximate Bayesian computation (ABC) and our results suggest that the current phylogeographic pattern of this species result from several deep vicariant events during Plio-Pleistocene. To conclude, this study revealed an unexpected high level of intraspecific diversity within L. neilli. These results consolidate the importance to strengthen the protection of limestone habitats and to preserve not only their high interspecific but also intraspecific diversity. [less ▲] Detailed reference viewed: 10 (0 ULg) Phylogeography and taxonomy of woodmice (Apodemus sylvaticus) populations from Western Palearctic: RFLP of the mtDNA variability; Libois, Roland ; et alin Ylönen, Hannu; Hentonnen, Heikki; Laajalahti, Päivi (Eds.) et al 3rd European congress of mammalogy (1999, May) Detailed reference viewed: 11 (0 ULg) Phylogeography of a nematode (Heligmosomoides polygyrus) in the western Palearctic region: persistence of northern cryptic populations during ice ages?Nieberding, Caroline M. ; Libois, Roland ; et alin Molecular Ecology (2005), 14(3), 765-79 This study establishes the continental phylogeographical pattern of a European nematode, Heligmosomoides polygyrus (Dujardin, 1845; Heligmosomoidea). We sequenced 687 base pairs of the mitochondrial DNA ... [more ▼] This study establishes the continental phylogeographical pattern of a European nematode, Heligmosomoides polygyrus (Dujardin, 1845; Heligmosomoidea). We sequenced 687 base pairs of the mitochondrial DNA (mtDNA) cyt b gene for 136 individuals collected in 22 localities. The results revealed that H. polygyrus populations are separated into five major units corresponding to the Italian, northern European (Denmark and Ireland), Iberian, western European, and Balkan populations. Different subclades were also observed within the first two groups. Based on the rate of molecular evolution of H. polygyrus cyt b gene-estimated to 3.5%-3.7% divergence per million years (Myr) in a previous study--the isolation time of the five clades was estimated between 2.5 +/- 0.24 and 1.5 +/- 0.23 million years ago. Moreover, H. polygyrus presents a higher genetic variability in the Mediterranean peninsulas as compared to northwestern Europe, highlighting the role of these regions as refuge areas. Like its specific host, the wood mouse Apodemus sylvaticus, H. polygyrus' pattern of postglacial recolonization of northwestern Europe was initiated from Iberian populations, while Italian and Balkan populations did not expand to the north. The results also suggest the existence of forested and temperate refuges in the southern British Isles during the Quaternary. Finally, the genetic diversity as well as the level of genetic divergence between the lineages of H. polygyrus are compared to those observed in other vertebrate and invertebrate phylogeographical studies: the existence of highly differentiated lineages in H. polygyrus (5%-10% of genetic divergence) highlights that the effects of Pleistocene climate changes on free-living organisms are also reflected in their obligate parasites. [less ▲] Detailed reference viewed: 17 (3 ULg) Phylogeography of Harbour Porpoise (Phocoena phocoena) in the Eastern North Atlantic and in the Black Sea Explored by the Analyses of Nuclear and Mitochondrial DNA; ; et al Poster (2005) Study of the genetic population structure and the demographic history of the harbour porpoise (Phocoena phocoena) has been nearly comprehensive throughout its distribution in North Atlantic, most studies ... [more ▼] Study of the genetic population structure and the demographic history of the harbour porpoise (Phocoena phocoena) has been nearly comprehensive throughout its distribution in North Atlantic, most studies using the mitochondrial control region as a genetic marker. Although these studies have shown population structure in some parts of the North Atlantic, mitochondrial DNA is a single, maternally inherited locus and therefore insufficient to fully characterize population structure and history. Polymorphism at 11 microsatellite loci was analyzed in harbour porpoises collected throughout the range of the species in the Central and Eastern North Atlantic from the Iberian peninsula northward to Arctic waters (Portugal, Spain, bay of Biscay, Irish waters, English Channel, the southern bay of the North Sea, Norway, Faroe Islands, and Iceland) and also along the coasts of the Black Sea (Turkey, Ukraine, Bulgaria and Georgia). Multilocus tests for allele frequency differences and population structure estimates indicate complete genetic isolation between Atlantic and Black Sea porpoises. No fine population structure was observed within the Black Sea, and this population displayed a low genetic diversity compared to those of Atlantic. These results can be interpreted in the light of the demographic history of this relict population and the strong founder effect and bottleneck it may have undergone in its past evolution. In Eastern North Atlantic waters, microsatellite data revealed fine scale partitioning of the genetic variation. These results will be compared to the pattern previously reported based on the analysis of the mtDNA control region, and seem to correlate with variation in oceanographic features. [less ▲] Detailed reference viewed: 35 (4 ULg) Phylogeography of the garden dormouse Eliomys quercinus in the western Palearctic region; Libois, Roland ; in Journal of Mammalogy (2012), 93(6), The garden dormouse, Eliomys quercinus (Rodentia, Gliridae), displays a surprisingly high karyotypic diversity, with the number of chromosomes varying between 2N ¼ 48 and 2N ¼ 54. We aimed to assess ... [more ▼] The garden dormouse, Eliomys quercinus (Rodentia, Gliridae), displays a surprisingly high karyotypic diversity, with the number of chromosomes varying between 2N ¼ 48 and 2N ¼ 54. We aimed to assess whether the karyotypic diversity is congruent with the mitochondrial differentiation of the populations; improve our understanding of the taxonomic relationships between garden dormouse populations based on both chromosomal and mitochondrial information; and establish the phylogeographic history of the species and the time of differentiation of mitochondrial lineages of E. quercinus and E. melanurus. For this purpose we sequenced the mitochondrial cytochrome-b (Cytb) gene for 62 E. quercinus and 4 E. melanurus from 27 localities representing all the known chromosomal races of the genus Eliomys in the western Palearctic region. Our results 1st showed that populations of E. quercinus are separated into 4 evolutionarily significant units partially congruent with the chromosomal races and corresponding to Iberian (2N¼48), Italian (2N¼48 or 50), western European (2N¼48, 49, or 50), and Alpine (2N ¼ 52 or 54) mitochondrial lineages or clades. The existence of hybrid individuals between chromosomal races and the presence of several chromosomal races within each mitochondrial lineage both indicate that gene flow persists between chromosomal races. Second, we estimated that the major mitochondrial lineages differentiated from each other around 4.2 6 SD 1 million years ago, thus predating the Quaternary glaciations. Third, E. quercinus displayed a higher haplotypic variability in the Mediterranean peninsula than in the northwestern European populations. However, E. quercinus did not show a pattern of ostglacial recolonization of northwestern Europe from Iberian or Italian populations. Our results also suggest that additional, unexpected refuge regions around the Alps exist for the species. Such information will be useful for deciphering the priorities for the protection of E. quercinus, which is listed as ‘‘Near Threatened’’ on the International Union for the Conservation of Nature Red List of Threatened Species and is protected by Appendix III of the Bern Convention. [less ▲] Detailed reference viewed: 38 (5 ULg) Physical activity and cardiovascular risk factors in children. The Belgian Luxembourg Child Study.Guillaume, Michèle ; ; in Obesity Research (1997) Detailed reference viewed: 12 (0 ULg) Physical activity patterns of children after neonatal arterial switch operation.; ; Gérard, Paul et alin Annals of Thoracic Surgery (2006), 81(2), 665-70 BACKGROUND: Physical inactivity is a major atherosclerosis risk factor. The exercise tolerance is usually excellent after neonatal arterial switch operation, but those patients in whom coronary anomalies ... [more ▼] BACKGROUND: Physical inactivity is a major atherosclerosis risk factor. The exercise tolerance is usually excellent after neonatal arterial switch operation, but those patients in whom coronary anomalies remain the main late complication, risk developing atherosclerotic coronary disease owing to perceived physical activity restrictions. METHODS: We investigated physical activity patterns of 52 unselected children 7 to 14 years after neonatal arterial switch operation for transposition of the great arteries by 24-hour continuous heart rate monitoring. The percentage of heart rate reserve was used to measure the amounts of activities. Comparisons were made with 35 children with repaired atrial or ventricular septal defect and with 127 age-matched healthy children. RESULTS: Children after arterial switch operation accumulated 167.3 +/- 70.6, 25.3 +/- 12.9, and 15.7 +/- 11.3 minutes a day (mean +/- SD) of light, moderate, and vigorous physical activities, respectively. At the same activity levels, children with repaired septal defect accumulated 165.2 +/- 82.2, 26.2 +/- 11.7, and 16.2 +/- 9.1 minutes a day, and their healthy peers 164.8 +/- 74.5, 31.8 +/- 13.9, and 21.9 +/- 11.3 minutes a day. Both cardiac groups were significantly less active than the control group when considering moderate (p = 0.026) and vigorous activities (p = 0.006). Only 19% and 27% of the children after arterial switch operation engaged, respectively, in more than 30 minutes a day of moderate activity and 20 minutes a day of vigorous activity. CONCLUSIONS: Children after arterial switch operation, just like other cardiac children, do not meet the guidelines for physical activity. We should encourage regular physical activity to offset adult sedentary behavior and to prevent atherosclerotic cardiovascular disease in those patients whose long-term function of the coronary arteries remains a matter of concern. [less ▲] Detailed reference viewed: 6 (0 ULg) Physical Activity Promotion In Overweight/Obese Children. A Project Implemented In A Hospital ContextCloes, Marc ; ; LEBRETHON, Marie-Christine ![]() Conference (2012) BACKGROUND. Overweight and obesity in youth must be combated through a multiple approach combining management principles in nutrition and physical activity (PA). In the hospital context, medical staff ... [more ▼] BACKGROUND. Overweight and obesity in youth must be combated through a multiple approach combining management principles in nutrition and physical activity (PA). In the hospital context, medical staff seems to be more focused on nutrition. AIM. In this study, we proposed to implement a specific intervention focusing on PA in parallel with traditional paediatric and dietetic visits designed to 6-12 year-old children. METHODS. Data were collected in three steps: (1) after a visit at the hospital, subjects and their parents answered to a questionnaire (lifestyle, representation about PA) and attended to a meeting during which they received written (illustrated booklet) and oral cues about PA as well as an invitation to use a PA diary and a pedometer; (2) before the next visit (almost 8 weeks interval), they were free to apply the recommendations; (3) after the next visit to the hospital, subjects analyzed the diary with one of the researchers and answered to questions about their current lifestyle and representations about PA. 34 children respected the whole protocol. FINDINGS. Among the children and their parents, representations of PA changed between the visits (PA was no longer regarded merely as sport). Major changes were also identified in children’s lifestyle (increase of number of weekly PA, family PA, weekly PA time; decrease of inactivity time like TV or video games). Only 27 children out of 34 used the PA diary at least once (information were recorded for a mean of 18 days/child between the 2 visits – a third of the duration of the interval). The pedometer has been used by 15 children and was considered as a motivating tool. 58.5% of comments collected at the end of the second meeting were positive and emphasized the interest of the intervention; 24.6% were negative and mainly focused the PA diary). DISCUSSION. This study underlines the need to improve the family's representations about PA in paediatric and dietetic visits. It supports PA experts' integration in the staff. [less ▲] Detailed reference viewed: 25 (5 ULg) Physical activity, obesity, and cardiovascular risk factors in children. The Belgian Luxembourg Child Study II.Guillaume, Michèle ; ; et alin Obesity Research (1997), 5(6), 549-56 Physical activity was measured in relation to cardiovascular (CV) risk factors in a randomly selected population of 1028 children from Province de Luxembourg in Belgium, a mainly rural area with a high ... [more ▼] Physical activity was measured in relation to cardiovascular (CV) risk factors in a randomly selected population of 1028 children from Province de Luxembourg in Belgium, a mainly rural area with a high prevalence of such risk factors among adults and children. Physical activity was estimated as participation in sport activities, a major indicator of leisure-time physical activity in schoolchildren, and physical inactivity was estimated as frequency and duration of television (TV) watching. Boys participated more frequently in sport activities than girls did (p = 0.001). A majority of the children watched TV daily. After age adjustment, bodyweight (girls, p < 0.012; boys, p < 0.027) and, in boys, body mass index (BMI) (p < 0.039) were related to days per week of TV watching. No significant relationships with other CV risk factors remained after adjustments for BMI. In analyses of independent contributions of age, TV watching, and sports activity on CV risk factors, age showed highly significant relationships. In boys, TV showed relationships with BMI (p < 0.04) and (borderline) with systolic blood pressure, independent of age and sports activity, whereas the latter was significantly related to subscapular skinfold (p < 0.04) and (borderline) with triceps skinfold and cholesterol. In girls, no significant independent contributions to risk factor associations were found. The father's education was directly associated with sports activities, whereas the mother being a housewife showed negative relationships to physical activity and positive to TV watching in their children, suggesting socioeconomic influence on the activity patterns of children. Furthermore, registrations suggested less physical activity in the most rural part of the area. It is concluded that children in this mainly rural area watch TV frequently. In boys, physical inactivity, measured both as TV watching and as registrations of sports activities, contributes independently to body fat mass. In girls, no contribution or weaker contributions of physical inactivity were found. This suggests that contributory factors leading to obesity might be different in girls and boys. [less ▲] Detailed reference viewed: 25 (7 ULg) Physical and chemical characteristics of natural limestone fillers: mix properties and packing densityCourard, Luc ; Pirard, Eric ; Scientific conference (2012) Detailed reference viewed: 29 (1 ULg) Physical and chemical properties of pyropheophorbide)a-methyl ester in ethanol, phosphate buffer and aqueous dispersion of small unilamellar dimyristoyl-L-a-phosphatidylcholine vesicles; Bahri, Mohamed Ali ; et alin Photochemical & Photobiological Sciences (2006), 5 The aggregation process of pyropheophorbide-a methyl ester (PPME), a second generation hotosensitizer, was investigated in various solvents. Absorption and fluorescence spectra showed that the ... [more ▼] The aggregation process of pyropheophorbide-a methyl ester (PPME), a second generation hotosensitizer, was investigated in various solvents. Absorption and fluorescence spectra showed that the photosensitizer was under a monomeric form in ethanol as well as in dimyristoyl-L-α-phosphatidylcholine liposomes while it was strongly aggregated in phosphate buffer. A quantitative determination of reactive oxygen species production by PPME in these solvents has been undertaken by electron spin resonance associated with spin trapping technique and absorption spectroscopy. In phosphate buffer, both electron spin resonance and absorption measurements led to the conclusion that singlet oxygen production was not detectable while hydroxyl radical production was very weak. In liposomes and ethanol, singlet oxygen and hydroxyl radical production increased highly; the singlet oxygen quantum yield was determined to be 0.2 in ethanol and 0.13 in liposomes. The hydroxyl radical production origin was also investigated. Singlet oxygen was formed from PPME triplet state deactivation in presence of oxygen. Indeed, the triplet state formation quantum yield of PPME was found to be about 0.23 in ethanol, 0.15 in liposomes (too small to be measured in PBS). [less ▲] Detailed reference viewed: 17 (4 ULg) Physical and mechanical properties of black locust (Robinia pseudoacacia) wood grown in Belgium; ; Hebert, Jacques et alin Revue canadienne de recherche forestière (2012), 42(5), 831-840 The objective of this study was to characterize black locust (Robinia pseudoacacia L.) wood on the basis of its physical and mechanical properties. The results are compared with those reported in the ... [more ▼] The objective of this study was to characterize black locust (Robinia pseudoacacia L.) wood on the basis of its physical and mechanical properties. The results are compared with those reported in the literature for English oak (Quercus robur L.), teak (Tectona grandis L. f.), and afzelia (Afzelia sp.), since black locust is likely to be used for the same purposes as the former species. The variations between sites, trees, and radial positions in the trunk were also studied. The physical and mechanical properties of black locust wood were evaluated on clear wood specimens taken from 27 trees distributed over five sites in Wallonia (Belgium) according to Belgian and French standards. Most of the black locust’s mechanical properties are higher than those of oak and teak. The black locust is classified as a “mid-heavy” (734 kg·m–3) and “half-hard” (5.22) wood type with very high resilience (17.2 J·cm–2), modulus of elasticity (15 700 MPa), and tensile strength in static bending (138 MPa). Its resilience is exceptional, higher than that of teak and afzelia, while its modulus of elasticity and bending strength, which surpass those of teak, are comparable with those of afzelia. Black locust shows high total volumetric shrinkage (16%), placing it in the “nervous” class, average tangential (8.8%) and radial shrinkage (5.5%) as well as average axial compressive (63 MPa) and splitting strength (17.8 N·mm–1). No technological incompatibilities would prevent the use of this wood for many value-added purposes (floor, deck, exterior woodwork, and furniture); however, significant shrinkage makes it necessary to condition the wood to its service moisture. [less ▲] Detailed reference viewed: 55 (33 ULg) Physical and numerical modeling of overbank flow with a groyne on the floodplainPeltier, Yann ; ; et alin River Flow 2008: 4th Int. Conf. on Fluvial Hydraulics (2008) Detailed reference viewed: 4 (0 ULg) Physical and physiological impacts of different foam control strategies during a process involving hydrophobic substrate for the lipase production by Yarrowia lipolyticaKar, Tambi ; Destain, Jacqueline ; Thonart, Philippe et alin Bioprocess and Biosystems Engineering (2012), 35(4), 483-492 The potentialities for the intensification of the process of lipase production by the yeast Yarrowia lipolytica on a renewable hydrophobic substrate (methyloleate) have been investigated. The key factor ... [more ▼] The potentialities for the intensification of the process of lipase production by the yeast Yarrowia lipolytica on a renewable hydrophobic substrate (methyloleate) have been investigated. The key factor governing the lipase yield is the intensification of the oxygen transfer rate, considering the fact that Y. lipolytica is a strict aerobe. However, considering the nature of the substrate and the capacity for protein excretion and biosurfactant production of Y. lipolytica, intensification of oxygen transfer rate is accompanied by an excessive formation of foam. Two different foam control strategies have thus been implemented: a classical chemical foam control strategy (CFM) and a mechanical foam control (MFM) based on the Stirring As Foam Disruption (SAFD) principle. The second strategy allows foam control without any modifications of the physico-chemical properties of the broth. However, the MFM system design induced the formation of a persistent foam layer in the bioreactor. This phenomenon has led to the segregation of microbial cells between the foam phase and the liquid phase in the case of the bioreactors operated with MFM control, and induced a reduction at the level of the lipase yield. More interestingly, flow cytometry experiments have shown that residence time of microbial cells in the foam phase tends to induce a dimorphic transition which could potentially explain the reduction of lipase excretion. [less ▲] Detailed reference viewed: 24 (7 ULg) Physical and textural characteristics of hydrogenated low-erucic acid rapeseed oil and low-erucic acid rapeseed oil blendsDanthine, Sabine ; Deroanne, Claude ![]() in Journal of the American Oil Chemists' Society [=JAOCS] (2003), 80(2), 109-114 Low-erucic acid rapeseed oil (LERO) and hydrogenated low-erucic acid rapeseed oil (HLERO) were blended in binary systems. The blends were then studied for their physical properties such as solid fat ... [more ▼] Low-erucic acid rapeseed oil (LERO) and hydrogenated low-erucic acid rapeseed oil (HLERO) were blended in binary systems. The blends were then studied for their physical properties such as solid fat content, melting curves by DSC, textural properties, and polymorphism. Phase behavior diagrams were constructed from the DSC and X-ray results, and isosolid diagrams were constructed from the NMR results. The mixture of HLERO and LERO displayed a monotectic behavior for all the storage time at 15degreesC. The aim of this work was to evaluate physical characteristics of binary blends of HLERO and nonhydrogenated LERO in order to use only LERO and hardened LERO in bakery shortenings. The mixture of 60% HLERO and 40% LERO is suitable to use as a plastic shortening, This blend is beta tending upon storage at 15degreesC. It could be used in pie crust applications. [less ▲] Detailed reference viewed: 22 (8 ULg) |
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