Increasing crop heterogeneity enhances multitrophic diversity across agricultural regions

International audienceAgricultural landscape homogenization has detrimental effects on biodiversity and key ecosystem services. Increasing agricultural landscape heterogeneity by increasing seminatural cover can help to mitigate biodiversity loss. However, the amount of seminatural cover is generally low and difficult to increase in many intensively managed agricultural landscapes. We hypothesized that increasing the heterogeneity of the crop mosaic itself (hereafter “crop heterogeneity”) can also have positive effects on biodiversity. In 8 contrasting regions of Europe and North America, we selected 435 landscapes along independent gradients of crop diversity and mean field size. Within each landscape, we selected 3 sampling sites in 1, 2, or 3 crop types. We sampled 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders, and birds) and calculated a synthetic index of multitrophic diversity at the landscape level. Increasing crop heterogeneity was more beneficial for multitrophic diversity than increasing seminatural cover. For instance, the effect of decreasing mean field size from 5 to 2.8 ha was as strong as the effect of increasing seminatural cover from 0.5 to 11%. Decreasing mean field size benefited multitrophic diversity even in the absence of seminatural vegetation between fields. Increasing the number of crop types sampled had a positive effect on landscape-level multitrophic diversity. However, the effect of increasing crop diversity in the landscape surrounding fields sampled depended on the amount of seminatural cover. Our study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production

Athérosclérose carotidienne symptomatique (évolution de l'instabilité de la plaque selon le délai de l'accident cérébral)

LYON1-BU Santé (693882101) / SudocSudocFranceF

Influence of polymorphism on charge transport properties in isomers of fluorenone-based liquid crystalline semiconductors

International audienceWe measured the charge carrier mobilities for two isomers of fluorenone-based liquid crystalline organic semiconductors from their isotropic down to crystalline states through one or two mesophases. Improved charge transport properties of melt-processed crystalline films were obtained for the isomer exhibiting a highly ordered mesophase below its disordered smectic phase

Low WSS Induces Intimal Thickening, while Large WSS Variation and Inflammation Induce Medial Thinning, in an Animal Model of Atherosclerosis.

Atherosclerotic plaque development in the arterial wall is the result of complex interaction between the wall's endothelial layer and blood hemodynamics. However, the interaction between hemodynamic parameters and inflammation in plaque evolution is not yet fully understood. The aim of the present study was to investigate the relation between wall shear stress (WSS) and vessel wall inflammation during atherosclerotic plaque development in a minipig model of carotid stenosis.A surgical procedure was performed to create left common carotid artery stenosis by placement of a perivascular cuff in minipigs under atherogenic diet. Animals were followed up on 3T MRI, 1 week after surgery and 3, 6, and 8 months after initiation of the diet. Computational fluid dynamics simulation estimated WSS distribution for the first imaging point. Vascular geometries were co-registered for direct comparison of plaque development and features (Gadolinium- and USPIO-Contrast Enhanced MRI, for permeability and inflammation respectively) with the initial WSS. Histological analysis was performed and sections were matched to MR images, based on spatial landmarks.Vessel wall thickening, permeability and inflammation were observed distally from the stenosis. They were eccentric and facing regions of normal wall thickness. Histological analysis confirmed eccentric plaque formation with lipid infiltration, intimal thickening and medial degradation. High phagocytic activity in the stenosis region was co-localized with high WSS, corresponding to intense medial degradation observed on histology samples.Lower WSS promotes atherosclerotic plaque development distal to an induced stenosis. Vascular and perivascular inflammation locations were predominant in the high WSS stenosis segment, where medial thinning was the major consequence

Charge carrier mobility study of a mesogenic thienothiophene derivative in bulk and thin films

International audienc

Study flow-chart.

<p><b>HF/HC diet</b>: high fat/ high cholesterol atherogenic diet. <b>Blood analysis</b>: lipid profile and insulin resistance. <b>MRA</b>: MR angiography (stenosis geometry). <b>Wall Gd MRI</b>: Gadolinium contrast-enhanced high-resolution MRI (plaque area and vessel wall permeability). <b>Wall USPIO MRI</b>: P904 contrast-enhanced high-resolution MRI (vessel wall inflammation).</p

A-C: Baseline geometry of the left carotid artery stenosis on MRI angiography for the 3 animals: respectively 83%, 63% and 74% stenosis for animals #1, #2 and #3 (from left to right).

<p>A-C: Baseline geometry of the left carotid artery stenosis on MRI angiography for the 3 animals: respectively 83%, 63% and 74% stenosis for animals #1, #2 and #3 (from left to right).</p

A-E: Lower wall shear stress and post-gadolinium enhancement in the plaque-positive distal portion of the left carotid artery.

<p><b>A-C</b>. 3D WSS of animal #2 obtained by CFD in the right (RC) and left (LC) carotids (A); and location-matched (black line in A) WSS LC cross-section, showing transverse distribution of lower WSS areas (B). <b>C-D</b> Co-localized positive contrast on the post-Gd T1-weighted sequence (at 8 months) (C), and intimal thickening and lipid infiltration in the corresponding Oil Red O slice (D). <b>E</b>. Mean WSS values (Pa) corresponding to spatially matched regions of distal LC wall (plaque-positive ROIs) and control RC wall, showing lower values in the distal LC slices compared to control RC (* significant difference).</p