1,713 research outputs found

    Root traits explain different foraging strategies between resprouting life histories

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    11 páginas, 5 figuras, 2 tablas.Drought and fire are prevalent disturbances in Mediterranean ecosystems. Plant species able to regrow after severe disturbances (i. e. resprouter life history) have higher allocation to roots and higher water potential during the dry season than coexisting non-resprouting species. However, seedlings of non-resprouters have a higher survival rate after summer drought. We predict that, to counteract their shallow-rooting systems and to maximize seedling survival, non-resprouters have root traits that confer higher efficiency in soil resource acquisition than resprouters. We tested this prediction in seedlings of less than 1.5 months old. We select 13 coexisting woody species (including both resprouters and non-resprouters), grew them in a common garden and measured the following root traits: length, surface, average diameter, root tissue density (RTD), specific root length (SRL), surface:volume ratio (SVR), specific tip density (STD), tip distribution in depth, internal links ratio (ILR), and degree of branching. These root traits were compared between the two resprouting life histories using both standard cross-species and phylogenetic-informed analysis. Non-resprouters showed higher SRL and longer, thinner and more branched laterals, especially in the upper soil layers. The external links (i. e. the most absorptive root region) were also more abundant, longer, thinner and with higher SVR for non-resprouters. The results were supported by the phylogenetic-informed analysis for the root traits most strongly related to soil resource acquisition (SRL, SVR and branching pattern). The seedling root structure of non-resprouters species allows them to more efficiently explore the upper soil layer, whereas seedling roots of resprouters will permit both carbon storage and deep soil penetration.We thank all the volunteers for their help in the common garden and laboratory tasks, especially H. Simo˜es, J. Bandeira, C. Pérez-Cervelló, S. Ribeiro and B. Moreira. The Banc de Llavors Forestals of Generalitat Valenciana provided the installations for the common garden experiment. This work has been financed by the Spanish projects SINREG (REN2003-07198-C02-02/GLO), PERSIST (CGL2006-07126/BOS), and GRACCIE (CONSOLIDER– Ingenio 2010 program; CSD200-00067). CEAM is supported by the Generalitat Valencia and Bancaixa; CIDE is supported by the Generalitat Valencia and the University of Valencia.Peer reviewe

    On Endogenous Fissility of Argillites within Carbonous Deposits Of Donbass

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    Based on direct numerical simulations of forced turbulence, shear turbulence, decaying turbulence, a turbulent channel flow as well as a Kolmogorov flow with Taylor-based Reynolds numbers Reλ between 69 and 295, the normalized probability density function of the length distribution P(l) of dissipation elements, the conditional mean scalar difference Δkl at the extreme points as well as the scaling of the two-point velocity difference along gradient trajectories Δun are studied. Using the field of the instantaneous turbulent kinetic energy k as a scalar, we find good agreement between the model equation for P(l) as proposed by Wang and Peters (2008 J. Fluid Mech. 608 113–38) and the results obtained in the different direct numerical simulation cases. This confirms the independence of the model solution from both the Reynolds number and the type of turbulent flow, so that it can be considered universally valid. In addition, we show a 2/3 scaling for the mean conditional scalar difference. In the second part of the paper, we examine the scaling of the conditional two-point velocity difference along gradient trajectories. In particular, we compare the linear s/τ scaling, where τ denotes an integral time scale and s the separation arclength along a gradient trajectory in the inertial range as derived by Wang (2009 Phys. Rev. E 79 046325) with the sa∞ scaling, where a∞ denotes the asymptotic value of the conditional mean strain rate of large dissipation elements

    The Munich-Evaluation-of-Mentoring-Questionnaire (MEMeQ) - a novel instrument for evaluating protégés' satisfaction with mentoring relationships in medical education

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    Background Despite the widespread recognition of the importance of mentoring in medical education, valid and reliable instruments for evaluating the relationship of mentors and protégés are lacking. The aim of this study was to develop a feasible instrument to measure the satisfaction with mentoring relationships. Methods Based on two existing questionnaires, the authors developed an instrument to evaluate the weighted satisfaction of mentoring relationships, emphasizing the protégés' individual expectations and needs. Protégés first define individual areas of interest in their mentoring relationship, then assign relative levels of personal importance to them and finally rate their individual level of satisfaction with their mentors' support in each area of interest. In order to evaluate psychometric properties as well as acceptance and feasibility the investigators conducted a multi-method-study. Results 134 protégés were included in the study. The instrument was neither perceived as distressing nor time-consuming. The two scores of the questionnaire correlated closely with the overall satisfaction regarding mentoring relationships (OSM, Rho: 0.66, p <.001 and Rho: 0.53, p < .001). Conclusions The authors propose MEMeQ as a reliable, valid and flexible instrument for measuring the weighted satisfaction of protégés with their individual mentoring relationship in medical education. Further research is needed to evaluate the generalizability of MEMeQ across other institutions and mentoring programs to add to its validity

    One‐Pot Covalent Functionalization of 2D Black Phosphorus by Anionic Ring Opening Polymerization

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    In this work, a one‐pot approach for the covalent functionalization of few‐layer black phosphorus (BP) by anionic ring opening polymerization of glycidol to obtain multifunctional BP‐polyglycerol (BP‐PG) with high amphiphilicity for near‐infrared‐responsive drug delivery and biocompatibility is reported. Straightforward synthesis in combination with exceptional biological and physicochemical properties designates functionalized BP‐PG as a promising candidate for a broad range of biomedical applications

    Narcissistic self-sorting of n-acene nano-ribbons yielding energy-transfer and electroluminescence at p-n junctions

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    The 2,3-didecyloxy derivative of an n-type anthracene (n-BG) and a p-type tetracene (p-R) have been synthesized and their self-assembly into nano-ribbons studied. Hyperspectral fluorescence imaging revealed their narcissistic self-sorting, leading to separated nanoribbons emitting with very different colors (blue or green for n-BG, depending on the growth solvent, and red for p-R). It is unique that the usual origins of self-sorting, such as specific H-bonding, different growth kinetics, or incompatible steric hindrance can be ruled out. Hence, the narcissistic behaviour is herein proposed to originate from a sofar unconsidered cause: the discrepancy between the quadrupolar character of n-BG and dipolar character of p-R. At the p-n junctions of these nanoribbons, inter-ribbon FRET and electro-luminescence switch-on were observed by fluorescence/luminescence microscopy.The authors acknowledge the financial support of the European Research Council Marie Curie Actions (FP7-PEOPLE-2012-ITN SMARTNET Grant agreement Nr 316656); the CNRS; the French Ministry of Education and Research; the Region Aquitaine; the ANR-06-JCJC-0030; the Department of Education, Science and Universities of the Basque Country Government (postdoctoral grant and project IT1639-22); the "Arina" informatic cluster of UPV/EHU; the facilities ELORGA of UB; and the ANR-17-CE24-0033-01 RESOLVE. The authors thank Dr A. Mendez-Ardoy for the CV measurements and CESAMO for structural analyses (ISM, Univ. Bordeaux)

    Role of NOD2/CARD15 in coronary heart disease

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    <p>Abstract</p> <p>Background:</p> <p>Bacterial DNA has been repeatedly detected in atheromatous lesions of coronary heart disease (CHD) patients. Phylogenetic signatures in the atheroma lesions that are similar to those of bacterial biofilms on human barrier organs, including the respiratory or gastrointestinal tract, raise the question of a defective barrier function in CHD. NOD2 plays a major role in defense against bacterial invasion. Genetic variation in the <it>CARD15 </it>gene, which encodes NOD2, was previously shown to result in a barrier defect that causes chronic inflammatory disorders (e.g. Crohn disease). In the present study, we investigated the possible involvement of NOD2/<it>CARD15 </it>in the pathology of CHD by <it>i) </it>analyzing the local expression of NOD2 in atherectomy versus healthy tissue (n = 5 each) using histochemical immunofluorescence and <it>ii) </it>by testing the three major functional <it>CARD15 </it>variants (R702W, G908R and 1007fs) for association with early-onset CHD in 900 German patients and 632 healthy controls.</p> <p>Results:</p> <p>In atherectomy tissue of CHD patients, NOD2 was detected in inflammatory cells at the luminal sides of the lesions. However, the allele and genotype frequencies of the three major <it>CARD15 </it>polymorphisms did not differ between CHD patients and controls.</p> <p>Conclusion:</p> <p>The NOD2 up-regulation in atheroma lesions indicates an involvement of this protein in the pathology of CHD. Although NOD2 could be important in local immune response mechanisms, none of the analyzed <it>CARD15 </it>variants seem to play a significant role in the etiology of CHD.</p

    Corrigendum to "Inhibition of HDACs reduces Ewing sarcoma tumor growth through EWS-FLI1 protein destabilization" [Neoplasia volume 27 (2022) pp. 100784/Number C]

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    Oncogenic transcription factors lacking enzymatic activity or targetable binding pockets are typically considered “undruggable”. An example is provided by the EWS-FLI1 oncoprotein, whose continuous expression and activity as transcription factor are critically required for Ewing sarcoma tumor formation, maintenance, and proliferation. Because neither upstream nor downstream targets have so far disabled its oncogenic potential, we performed a high-throughput drug screen (HTS), enriched for FDA-approved drugs, coupled to a Global Protein Stability (GPS) approach to identify novel compounds capable to destabilize EWS-FLI1 protein by enhancing its degradation through the ubiquitin-proteasome system. The protein stability screen revealed the dual histone deacetylase (HDAC) and phosphatidylinositol-3-kinase (PI3K) inhibitor called fimepinostat (CUDC-907) as top candidate to modulate EWS-FLI1 stability. Fimepinostat strongly reduced EWS-FLI1 protein abundance, reduced viability of several Ewing sarcoma cell lines and PDX-derived primary cells and delayed tumor growth in a xenograft mouse model, whereas it did not significantly affect healthy cells. Mechanistically, we demonstrated that EWS-FLI1 protein levels were mainly regulated by fimepinostat's HDAC activity. Our study demonstrates that HTS combined to GPS is a reliable approach to identify drug candidates able to modulate stability of EWS-FLI1 and lays new ground for the development of novel therapeutic strategies aimed to reduce Ewing sarcoma tumor progression
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