Hypoxia induces dilated cardiomyopathy in the chick embryo: mechanism, intervention, and long-term consequences

Background: Intrauterine growth restriction is associated with an increased future risk for developing cardiovascular diseases. Hypoxia in utero is a common clinical cause of fetal growth restriction. We have previously shown that chronic hypoxia alters cardiovascular development in chick embryos. The aim of this study was to further characterize cardiac disease in hypoxic chick embryos. Methods: Chick embryos were exposed to hypoxia and cardiac structure was examined by histological methods one day prior to hatching (E20) and at adulthood. Cardiac function was assessed in vivo by echocardiography and ex vivo by contractility measurements in isolated heart muscle bundles and isolated cardiomyocytes. Chick embryos were exposed to vascular endothelial growth factor (VEGF) and its scavenger soluble VEGF receptor-1 (sFlt-1) to investigate the potential role of this hypoxia-regulated cytokine. Principal Findings: Growth restricted hypoxic chick embryos showed cardiomyopathy as evidenced by left ventricular (LV) dilatation, reduced ventricular wall mass and increased apoptosis. Hypoxic hearts displayed pump dysfunction with decreased LV ejection fractions, accompanied by signs of diastolic dysfunction. Cardiomyopathy caused by hypoxia persisted into adulthood. Hypoxic embryonic hearts showed increases in VEGF expression. Systemic administration of rhVEGF165 to normoxic chick embryos resulted in LV dilatation and a dose-dependent loss of LV wall mass. Lowering VEGF levels in hypoxic embryonic chick hearts by systemic administration of sFlt-1 yielded an almost complete normalization of the phenotype. Conclusions/Significance: Our data show that hypoxia causes a decreased cardiac performance and cardiomyopathy in chick embryos, involving a significant VEGF-mediated component. This cardiomyopathy persists into adulthood

Fabrication and Characterization of Chalcogenide nano composite based materials for Photonic device applications

In this context,in search of new materials based on chalcogenide glasses,we have developed a novel technique for fabrication of chalcogenide nano composites which are presented in this theis.The techniques includes the dissolution of bulk chalcogenide glasses in amine solvent.This solution casting method allows to retain the attractive optical properties of chalcogenide glasses enabling new fabrication routes for realization of large area thick-thin films with less cost. Chalcogenide glass fiber geometry opens new possibilities for a large number of applications in optics,like remote temperature measurements ,CO2 laser power delivery, and optical sensing and single mode propagation of IR light.We have fabricated new optical polymer fibers doped with chalcogenide glasses which can be used for many optical applications.The present thesis also describes the structural,thermal and optical characterization of certain chalocogenide based materials prepared for different methods and its applications.International School of Photonics, Cochin University of Science and Technolog

Turnaround time prediction for clinical chemistry samples using machine learning

Objectives: Turnaround time (TAT) is an essential performance indicator of a medical diagnostic laboratory. Accurate TAT prediction is crucial for taking timely action in case of prolonged TAT and is important for efficient organization of healthcare. The objective was to develop a model to accurately predict TAT, focusing on the automated pre-analytical and analytical phase. Methods: A total of 90,543 clinical chemistry samples from Erasmus MC were included and 39 features were analyzed, including priority level and workload in the different stages upon sample arrival. PyCaret was used to evaluate and compare multiple regression models, including the Extra Trees (ET) Regressor, Ridge Regression and K Neighbors Regressor, to determine the best model for TAT prediction. The relative residual and SHAP (SHapley Additive exPlanations) values were plotted for model evaluation. Results: The regression-tree-based method ET Regressor performed best with an R2 of 0.63, a mean absolute error of 2.42 min and a mean absolute percentage error of 7.35%, where the average TAT was 30.09 min. Of the test set samples, 77% had a relative residual error of at most 10%. SHAP value analysis indicated that TAT was mainly influenced by the workload in pre-analysis upon sample arrival and the number of modules visited. Conclusions: Accurate TAT predictions were attained with the ET Regressor and features with the biggest impact on TAT were identified, enabling the laboratory to take timely action in case of prolonged TAT and helping healthcare providers to improve planning of scarce resources to increase healthcare efficiency

Differential accumulation of potassium in the vegetative and reproductive organs of three grapevine cultivars

Vine nutrition and vineyard fertilizer management have long-term implications for plant performance, notably vigour, crop load and fruit composition. Grape and wine composition is intrinsically linked to vineyard management practises. Wine sensory outcomes such as flavour, colour and aroma are heavily dependent upon intrinsic grape properties including pH, which in turn is influenced by berry potassium (K) concentration. Cultivar differences in the accumulation of nutrients is evident, however, tracking the accumulation of K in the various vine tissues is crucial for understanding how this macronutrient should be monitored during the season to achieve optimum growth performance and grape quality. We studied three economically important wine grape cultivars in Australia, grown under identical conditions, to determine how K accumulation differs between the cultivars, between the vegetative and reproductive organs and between two node positions on the shoot. The samples were collected at flowering and veraison and analysed for K by inductively coupled plasma atomic emission spectroscopy (ICP-AES). K concentrations ([K]) increased or decreased between these two phenological stages depending on cultivar, organ and node position. [K] in the berry and flower were not correlated with [K] in the leaf blade, petiole, or bunch stem. The differential accumulation of K in various organs points towards complex partitioning and mobilisation patterns, and this will have implications for berry pH and acidity at harvest. The differential accumulation of K between cultivars suggests that cultivar specific reference standards are required

Experimental demonstration and numerical study of plasmon-soliton waves

International audienceMerging the fields of plasmonics and nonlinear optics authorizes a variety of fascinating and original physical phenomena. In this work, we specifically study the combination of the strong light confinement ability of surface plasmon polaritons (SPP) with the beam self-trapping effect in a nonlinear optical Kerr medium. Although this idea of plasmon-soliton has been the subject of numerous theoretical papers since the eighties [1–4], up to now, no experimental evidence had been revealed yet. In the present study, a proper structure (Fig. 1a) has been designed and fabricated allowing the first experimental demonstration of these hybrid nonlinear waves merging spatial solitons and SPP

Evaluation of the Optical nonlinearities of Slab Waveguides by beam Self-Trapping

International audience&nbsp

Mesures de l'effet de Kerr dans des guides plans par analyse de faisceaux auto-pièges

International audienceNous présentons une nouvelle technique expérimentale basée sur l'analyse de faisceaux auto-piégés pour mesurer les non-linéarités Kerr dans des guides plans. Cette technique est appliquée pour analyser les propriétés non linéaires de guides constitués de verres de chalcogénure Ge-Sb-Se qui possèdent un effet Kerr autorisant la formation de solitons spatiaux. Les caractéristiques optiques linéaires et non linéaires de ces structures sont étudiées à 1550 nm en régime femtoseconde. Les coefficients non linéaires obtenus par la technique proposée sont en accord avec les valeurs publiées dans la littérature

Characterising leaf petiole, blade and bunchstem nutrient concentration across three grapevine cultivars

Background and Aims: Tissue nutrient concentration is useful for determining vine nutritional status and managing vineyard nutrition. Current Australian guidelines are based on the analysis of petioles at flowering and leaf blades at veraison, sampled adjacent to the basal inflorescence and bunch. The comparative value of these two tissue types and that of the bunchstem for assessing plant nutrient status at the two phenological stages is required. Moreover, the impact of node position and cultivar is unclear. Methods and Results: We characterised the macro and micronutrients at flowering and veraison of three segments of the petiole, the entire leaf blade and the bunchstem at two node positions of cvs Cabernet Sauvignon, Shiraz and Chardonnay grown under identical conditions. Nutrient concentration was non-uniform along the length of the petiole. The middle segment had the lowest concentration of most macronutrients, while Mn was generally highest in the middle segment. When averaged across petioles, blades and bunchstems the lower node had a higher nutrient concentration than the upper node, except for K. The concentration of some nutrients within the leaf blade was correlated with those of the petiole but this was dependent on the cultivar and the time of sampling. The nutrient concentration of the bunchstem was more closely correlated to the petiole than to the blade. Cultivar differences were also apparent, but this depended on the individual nutrient and the sampling time. Conclusions: Nutrient concentration was inconsistent along the length of the petiole. The nutrient concentration of petioles, blades and bunchstems was node, cultivar and time specific. Therefore, tissue nutrient analysis will be meaningful only if sampling is consistent across these variables. Significance of the Study: These results will aid in the formation of better sampling protocols for accurate grapevine nutrient diagnosis