|
|
Houel, E., Gonzalez, G., Bessière, J. - M., Odonne, G., Eparvier, V., Deharo, E., et al. (2015). Therapeutic switching: From antidermatophytic essential oils to new leishmanicidal products. Memorias do Inst. Oswaldo Cruz, 110(1), 106–113.
Abstract: This study examined whether the antidermatophytic activity of essential oils (EOs) can be used as an indicator for the discovery of active natural products against Leishmania amazonensis. The aerial parts of seven plants were hydrodistilled. Using broth microdilution techniques, the obtained EOs were tested against three strains of dermatophytes (Trichophyton mentagrophytes, Microsporum gypseum and Microsporum canis). To compare the EOs antifungal and antiparasitic effects, the EOs activities against axenic amastigotes of L. amazonensis were concurrently evaluated. For the most promising EOs, their antileishmanial activities against parasites infecting peritoneal macrophages of BALB/c mice were measured. The most interesting antifungal candidates were the EOs from Cymbopogon citratus, Otacanthus azureus and Protium heptaphyllum, whereas O. azureus, Piper hispidum and P. heptaphyllum EOs exhibited the lowest 50% inhibitory concentration (IC50) values against axenic amastigotes, thus revealing a certain correspondence between both activities. The P. hispidum EO was identified as the most promising product in the results from the infected macrophages model (IC50: 4.7 μg/mL, safety index: 8). The most abundant compounds found in this EO were sesquiterpenes, notably curzerene and furanodiene. Eventually, the evaluation of the antidermatophytic activity of EOs appears to be an efficient method for identifying new potential drugs for the treatment of L. amazonensis.
Keywords: Antifungal agents; Antiparasitic agents; Leishmania; Peritoneal macrophages – sesquiterpenes; Therapeutic switching
|
|
|
|
Pierrejean, I., Mehinto, T., & Beauchene, J. (2017). Comparative Analysis of Three Different Methods Used to Determine the Elastic Modulus for a Choice of Tropical Guianese Wood Species. Pro Ligno, 13(1), 3–17.
Abstract: This study compares variability in the longitudinal Modulus of Elasticity (MOE) values, measured by three different methods, for eight tropical wood species covering a wide range of densities, a property that has been little described in the literature for some of the species studied. The modulus of elasticity in wood species is one of the main mechanical properties measured to characterize wood materials. However, this property is seldom described for the tropical wood species studied here, and the method used is often variable. The aim is to answer the following questions. In the methods used, what are the main variability factors which influence modulus measurement? Is the modulus different with regard to the solicitation direction (radial or tangential)? Which relationship exists between modulus and density for these species?
The samples were subjected to the four-point bending test, then to the free vibration test and to the forced-vibration test (which allows tests on small samples).The samples were subjected to stress in radial and tangential directions. The modulus values obtained by the different methods were well correlated for most of the species. The relationship between modulus and density was very good at inter-specific level because sampling covered a wide range of densities. But this relationship was not so good for each of the species sampled.
This kind of test was not appropriate for detecting differences in behavior between the two directions of solicitation for these species. The main features of the three methods were summarized, highlighting the advantages of each for the species studied.
Keywords: density; modulus of elasticity; static and dynamic tests; tropical woods
|
|
|
|
Brémaud, I., Ruelle, J., Thibaut, A., & Thibaut, B. (2013). Changes in viscoelastic vibrational properties between compression and normal wood: Roles of microfibril angle and of lignin. Holzforschung, 67(1), 75–85.
Abstract: This study aims at better understanding the respective influences of specific gravity (γ ), microfibril angle (MFA), and cell wall matrix polymers on viscoelastic vibrational properties of wood in the axial direction. The wide variations of properties between normal wood (NW) and compression wood (CW) are in focus. Three young bent trees (Picea abies, Pinus sylvestris and Pinus pinaster ), which recovered verticality, were sampled. Several observed differences between NW and CW were highly significant in terms of anatomical, physical (γ, shrinkage, CIE Lab colorimetry), mechanical (compressive strength), and vibrational properties. The specific dynamic modulus of elasticity (E′/γ) decreases with increasing MFA, and Young's modulus (E′) can be satisfactorily explained by γ and MFA. Apparently, the type of the cell wall polymer matrix is not influential in this regard. The damping coefficient (tan δ) does not depend solely on the MFA of NW and CW. The tanδ-E′/γ relationship evidences that, at equivalent E′/γ, the tan δ of CW is approximately 34% lower than that of NW. This observation is ascribed to the more condensed nature of CW lignins, and this is discussed in the context of previous findings in other hygrothermal and time/frequency domains. It is proposed that the lignin structure and the amount and type of extractives, which are both different in various species, are partly responsible for taxonomy-related damping characteristics. Copyright © by Walter de Gruyter • Berlin • Boston.
Keywords: Compression wood (CW); Damping coefficient; Ft-Ir; Internal friction; Lignin; Microfibril angle (MFA); Picea abies; Pinus pinaster; Pinus sylvestris; Specific dynamic modulus of elasticity; Viscoelastic vibrational properties
|
|
|
|
Groc, S., Delabie, J. H. C., Cereghino, R., Orivel, J., Jaladeau, F., Grangier, J., et al. (2007). Ant species diversity in the 'Grands Causses' (Aveyron, France): In search of sampling methods adapted to temperate climates RID C-4034-2011. C. R. Biol., 330(12), 913–922.
Abstract: This study aimed at showing the applicability of using a combination of four sampling methods (i.e., Winkler extractors, pitfall traps, baiting and manual collection), something most often conducted in the tropics, to create an inventory of ant species diversity in temperate environments. We recorded a total of 33 ant species in the Grands Causses by comparing three vegetal formations: a steppic lawn ('causse' sensu stricto), which was the most species-rich (29 species), followed by an oak grove (22 species) and a pine forest (17 species). No sampling method alone is efficient enough to provide an adequate sampling, but their combination permits one to make a suitable inventory of the myrmecofauna and to obtain information on the ecology of these ant species.
Keywords: ant diversity; Grands Causses; sampling methods; temperate climate
|
|
|
|
Guitet, S., Blanc, L., Trombe, P. J., & Lehallier, B. (2009). Silvicultural Treatments in the Tropical Forests of Guiana: A Review of Ten Years of Trials. Bois For. Trop., 63(301), 7–19.
Abstract: This article reviews an experimental system set up in French Guiana to test different selective thinning methods that started ten to fifteen years after logging in order to reconstitute commercially viable stands within the shortest time. The thinning methods tested involve a combination of selective intervention within a radius of 10 metres around crop trees and systematic intervention applied uniformly to the entire forest parcel. The resulting thinning intensity produces an 8% to 45% reduction in basal area. While the growth of the residual stand is strongly boosted in all species and for all diameters, there is little change in basal area because of high mortality and lower recruitment of commercial species. Standing commercial capital, however, is strongly affected by the thinning operations as defined. In effect, these thinning methods that benefit crop stems do not meet the objective of shorter rotations in Guiana's tropical logging forests. On the other hand, the measurements made in under-treatment stands agree with those obtained at the Paracou experimental station and confirm the need to adopt long cutting cycles of more than fifty years to ensure that the extraction of valuable species is sustainable in the current logging context in French Guiana.
Keywords: cutting cycle; thinning; stand dynamics; logging; French Guiana
|
|
|
|
Sist, P., Blanc, L., Mazzei, L., Baraloto, C., & Aussenac, R. (2012). Current knowledge on overall post-logging biomass dynamics in Northern Amazonian forests. Bois Forets Tropiques, 66(314), 41–49.
Abstract: This article presents the effects of logging on the dynamics of above-ground biomass from the results of the post-logging study within two forests: Cikel in Eastern Pará, Brazil and Paracou in French Guiana. The main objective is to compare the impact of commercial logging on the regeneration of the aboveground biomass in these forests whose characteristics differ in terms of structure and growth. In both sites, the intensity of exploitation is a key factor in determining the loss of biomass and the time required for its regeneration. In Paracou, the regeneration of biomass lost during conventional logging of 10 trees per hectare takes 45 years and more than 100 years when operating with higher intensity (21 trees/ha ). In Cikel the forest biomass regenerates after 49 years harvesting 6 trees/ha and that takes 87 years after removal of 8 trees/ha. This regeneration needs similar time on both sites but with lower logging intensity at Cikel, in which felled trees are larger with a greater biomass than those of Paracou. This post-logging study has established a direct correlation of the dynamics of the biomass with the initial structure of the forest, as well as with the parameters of forest dynamics: mortality, growth and recruitment. The accumulation of biomass by the tree growth of the two remaining stands is a key parameter for the net carbon storage, while the contribution of recruitment in Paracou becomes significant only after 10 years after felling. Therefore in view to improve the growth of residual trees, it is compulsory to apply adequate silvicultural treatments such as selective thinning or removal of vines. While the two forests are geographically close enough, their regenerative abilities differ and because of the significant difference in size of the trees, the forest could tolerate more intensive harvesting in French Guiana.
Keywords: Above ground-biomass; Amazonian rainforests; Logging impact; Silviculture
|
|
|
|
Yamamoto, H., & Almeras, T. (2007). A mathematical verification of the reinforced-matrix hypothesis using the Mori-Tanaka theory. J. Wood Sci., 53(6), 505–509.
Abstract: This article presents a theoretical verification of the reinforced-matrix hypothesis derived from tensor equations, σ W = σ f + σ m and ε W = ε f = ε m (Wood Sci Technol 32:171–182, 1998; Wood Sci Technol 33:311–325, 1999; J Biomech Eng 124:432–440, 2002), using classical Mori-Tanaka theory on the micromechanics of fiber-reinforced materials (Acta Metall 21:571–574, 1973; Micromechanics — dislcation and inclusions (in Japanese), pp 141–147, 1976). The Mori-Tanaka theory was applied to a small fragment of the cell wall undergoing changes in its physical state, such as those arising from sorption of moisture, maturation of wall components, or action of an external force, to obtain ⟨σ A⟩D = ϕ·⟨σ F⟩I + (1−ϕ)·⟨σ M⟩D−I. When the constitutive equation of each constituent material was applied to the equation ⟨σ A⟩D = ϕ·⟨σ F⟩I + (1−ϕ)·⟨σ M⟩D−I, the equations σ W = σ f + σ m and ε W = ε f = ε m were derived to lend support to the concept that two main phases, the reinforcing cellulose microfibril and the lignin-hemicellulose matrix, coexist in the same domain. The constitutive equations for the cell wall fragment were obtained without recourse to additional parameters such as Eshelby’s tensor S and Hill’s averaged concentration tensors AF and AM. In our previous articles, the coexistence of two main phases and σ W = σ f + σ m and ε W = ε f =ε m had been taken as our starting point to formulate the behavior of wood fiber with multilayered cell walls. The present article provides a rational explanation for both concepts.
Keywords: Engineering
|
|
|
|
Arranz, S. E., Avarre, J. - C., Balasundaram, C., Bouza, C., Calcaterra, N. B., Cezilly, F., et al. (2013). Permanent Genetic Resources added to Molecular Ecology Resources Database 1 December 2012-31 January 2013. Mol. Ecol. Resour., 13(3), 546–549.
Abstract: This article documents the addition of 268 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Alburnoides bipunctatus, Chamaerops humilis, Chlidonias hybrida, Cyperus papyrus, Fusarium graminearum, Loxigilla barbadensis, Macrobrachium rosenbergii, Odontesthes bonariensis, Pelteobagrus vachelli, Posidonia oceanica, Potamotrygon motoro, Rhamdia quelen, Sarotherodon melanotheron heudelotii, Sibiraea angustata, Takifugu rubripes, Tarentola mauritanica, Trimmatostroma sp. and Wallago attu. These loci were cross-tested on the following species: Alburnoides fasciatus, Alburnoides kubanicus, Alburnoides maculatus, Alburnoides ohridanus, Alburnoides prespensis, Alburnoides rossicus, Alburnoides strymonicus, Alburnoides thessalicus, Alburnoides tzanevi, Carassius carassius, Fusarium asiaticum, Leucaspius delineatus, Loxigilla noctis dominica, Pelecus cultratus, Phoenix canariensis, Potamotrygon falkneri, Trachycarpus fortune and Vimba vimba. © 2013 Blackwell Publishing Ltd.
|
|
|
|
Andris, M., Aradottir, G. I., Arnau, G., Audzijonyte, A., Bess, E. C., Bonadonna, F., et al. (2010). Permanent Genetic Resources added to Molecular Ecology Resources Database 1 June 2010-31 July 2010. Mol. Ecol. Resour., 10(6), 1106–1108.
Abstract: This article documents the addition of 205 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Bagassa guianensis, Bulweria bulwerii, Camelus bactrianus, Chaenogobius annularis, Creontiades dilutus, Diachasmimorpha tryoni, Dioscorea alata, Euhrychiopsis lecontei, Gmelina arborea, Haliotis discus hannai, Hirtella physophora, Melanaphis sacchari, Munida isos, Thaumastocoris peregrinus and Tuberolachnus salignus. These loci were cross-tested on the following species: Halobaena caerulea, Procellaria aequinoctialis, Oceanodroma monteiroi, Camelus ferus, Creontiades pacificus, Dioscorea rotundata, Dioscorea praehensilis, Dioscorea abyssinica, Dioscorea nummularia, Dioscorea transversa, Dioscorea esculenta, Dioscorea pentaphylla, Dioscorea trifida, Hirtella bicornis, Hirtella glandulosa, Licania alba, Licania canescens, Licania membranaceae, Couepia guianensis and 7 undescribed Thaumastocoris species.
|
|
|
|
Lehnebach, R., Beyer, R., Letort, V., & Heuret, P. (2018). Corrigendum: The pipe model theory half a century on: A review (Annals of Botany DOI: 10.1093/aob/mcx194). Annals of Botany, 121(7), 1427.
Abstract: There was an error in the affiliations of Véronique Letort. The correct affiliation is Laboratory of Mathematics in Interaction with Computer Science (MICS), CentraleSupélec, France The online paper has been corrected.
|
|
