Leaf morphological differentiation between Quercus robur and Quercus petraea is stable across western European mixed oak stands

© INRA, EDP Sciences 2002Leaf morphology was assessed in nine mixed oak stands (Quercus petraea and Q. robur ) located in eight European countries. Exhaustive sampling was used in an area of each stand where the two species coexisted in approximately equal proportions (about 170 trees/species/stand). Fourteen leaf characters were assessed on each of 5 to10 leaves collected from the upper part of each tree. Three multivariate statistical techniques (CDA, canonical discriminant analysis; PCA, principal component analysis; MCA, multiple correspondence analysis) were used in two different ways: first on the total set of leaves over all stands (global analysis) and second, separately within each stand (local analysis). There was a general agreement of the results among the statistical methods used and between the analyses conducted (global and local). The first synthetic variable derived by each multivariate analysis exhibited a clear and sharp bimodal distribution, with overlapping in the central part. The two modes were interpreted as the two species, and the overlapping region was interpreted as an area where the within-species variations were superimposed. There was no discontinuity in the distribution or no visible evidence of a third mode which would have indicated the existence of a third population composed of trees with intermediate morphologies. Based on petiole length and number of intercalary veins, an "easy to use" discriminant function applicable to a major part of the natural distribution of the species was constructed. Validation on an independent set of trees provided a 98% rate of correct identification. The results were interpreted in the light of earlier reports about extensive hybridization occurring in mixed oak stands. Maternal effects on morphological characters, as well as a lower frequency or fitness of hybrids in comparison with parent species could explain the maintenance of two modes, which might be composed of either pure species or pure species and introgressed forms.Antoine Kremer, Jean Luc Dupouey, J. Douglas Deans, Joan Cottrell, Ulrike Csaikl, Reiner Finkeldey, Santiago Espinel, Jan Jensen, Jochen Kleinschmit, Barbara Van Dam, Alexis Ducousso, Ian Forrest, U. Lopez de Heredia, Andrew J. Lowe, Marcela Tutkova, Robert C. Munro, Sabine Steinhoff and Vincent Badea

Renal clearable catalytic gold nanoclusters for in vivo disease monitoring

Ultra-small gold nanoclusters (AuNCs) have emerged as agile probes for in vivo imaging, as they exhibit exceptional tumour accumulation and efficient renal clearance properties. However, their intrinsic catalytic activity, which can enable increased detection sensitivity, has yet to be explored for in vivo sensing. By exploiting the peroxidase-mimicking activity of AuNCs and the precise nanometer size filtration of the kidney, we designed multifunctional protease nanosensors that respond to disease microenvironments to produce a direct colorimetric urinary readout of disease state in less than 1 h. We monitored the catalytic activity of AuNCs in collected urine of a mouse model of colorectal cancer where tumour-bearing mice showed a 13-fold increase in colorimetric signal compared to healthy mice. Nanosensors were eliminated completely through hepatic and renal excretion within 4 weeks after injection with no evidence of toxicity. We envision that this modular approach will enable rapid detection of a diverse range of diseases by exploiting their specific enzymatic signatures

Biowastes-to-biofuels routes via gasification

Nowadays, biomass has a well-known potential for producing energy calTiers, such as electricity, heat (steam) and transport biofuels. However, biomass availability is rather limited and stochastically distributed. This could be a major problem in demographically dense regions where land is scarce and biomass may compete with other applications, notably agriculture for food production. In fact, this is the case for the first-generation biofuels (e.g. bioethanol and biodiesel) that are mainly produced from biochemical conversion of food crops such as sugar cane, com or wheat, and vegetable oils from feedstock like rapeseed or palm oil. Moreover, when taking into account emissions from transport and conversion treatments, life-cycle analyses reveal that first-generation biofuels frequently exceed the emission thresholds of fossil fuels . Second generation biofuels are now being developed as a possible better alternative to the first generation, as they can use non-food crops (e.g. switch grass) or biowastes from different origins (e.g., forest, agriculture, industry, municipalities). Second generation biofuels can also be produced via either biochemical or thennochemical conversion. Among all the existing thermochemical conversion technologies, gasification is gaining interest due to its higher efficiency, larger scales, and reliable operation. However, biowastes-to-biofuels conversion involves several challenges. Firstly, the existing technology must be fe-designed and optimized to become cost and efficiency competitive with fossil fuels. Moreover, due to the wide diversity of biowastes and biofuels that can be obtained, the most sustainable conversion routes must be properly selected. Hence, an inherent challenge is to develop a reliable model to evaluate the sustainabililY of any process. In this chapter we present the evaluation of second generation biofuels (SNG, methanol, Fischer-lropsch fuels, hydrogen) as well as heat and electricity, from different biowastes via gasification with subsequent catalytic conversion of syngas. Pre-treatment steps are also considered in order to enhance the low energy density of biomass prior to gasification. However, since pre-treatment is directly affected by local conditions, the Dutch province of Friesland is taken as a case study. The biowaste-to-biofuels routes are modeled in Aspen Plus, and mass and energy balances obtained from simulations are later used for efficiency evaluation. Results are presented in terms of mass conversion yield, energy and exergetic efficiency. The last part of the paper is devoted to explain how those results will be integrated for combined economic and environmental impact analysis