The SuperCam Instrument Suite on the Mars 2020 Rover: Science Objectives and Mast-Unit Description

On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2-7 m, while providing data at sub-mm to mm scales. We report on SuperCam's science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.In France was provided by the Centre National d'Etudes Spatiales (CNES). Human resources were provided in part by the Centre National de la Recherche Scientifique (CNRS) and universities. Funding was provided in the US by NASA's Mars Exploration Program. Some funding of data analyses at Los Alamos National Laboratory (LANL) was provided by laboratory-directed research and development funds

0301 : Effects of low and high polyphenols content lettuces consumption on high fat diet induced metabolic syndrome and endothelial dysfunction

Consumption of vegetables has been recommended to reduce the risk of cardiovascular disease. The protection against disease is partly due to bioactive molecules including polyphenols. In order to evaluate the effects of such polyphenols, we supplemented High Fat diet rats with low and high polyphenolic content lettuces. 32 Wistar rats were divided in 4 groups, a control group (Ctrl), a high fat and sucrose diet group (HFS, 60% fat+10%sucrose) and 2 groups that after 6 weeks of HFS diet were supplemented 8 weeks with both HFS diet and either a low or high polyphenol content lettuces (HFS-LP; Blond Oak Leaf, 30g/day vs. HFS-HP; Red Oak Leaf, 30g/day). After 14 weeks of HF diet including 8 weeks of supplementation, we performed a glucose tolerance test and an evaluation of arterial blood pressure (BP) by tail cuff method. Then, aortic endothelial function and eNOS dependent vasodilatation were evaluated ex vivo on isolated rings. Firstly, we observed a higher body weight in HFS group (502±21g) compared to Ctrl group (417±14g) without any effect of both supplementations. Regarding glycemic control, HFS group presented increased fasting blood glucose (1,37g/l vs. 1,20g/l) as well as an impairment of glucose tolerance. Interestingly, both groups with lettuces intake displayed healthy fasting blood glucose values (1.14g/l and 1.15g/l) and an improvement of glucose tolerance. Moreover, both lettuces treatments managed to normalize the increase in mean BP observed in HFS group (HFS; 131mmHg; HFS-LP 120 mmHg; HFS-HP, 117mmHg). However, no effect of lettuce consumption was observed on endothelial dysfunction and impaired eNOS dependent vasodilatation observed in HFS rats. In conclusion, we observed in this study a major effect of lettuce intake on glycemic control as well as arterial BP. However, no effect regarding the difference in polyphenols content has been reported here underlying that the effects were independent of the specific polyphenols contained in the HP lettuce

Myocardial glucotoxicity: Mechanisms and potential therapeutic targets.

Besides coronary artery disease, which remains the main cause of heart failure in patients with diabetes, factors independent of coronary artery disease are involved in the development of heart failure in the onset of what is called diabetic cardiomyopathy. Among them, hyperglycaemia - a hallmark of type 2 diabetes - has both acute and chronic deleterious effects on myocardial function, and clearly participates in the establishment of diabetic cardiomyopathy. In the present review, we summarize the cellular and tissular events that occur in a heart exposed to hyperglycaemia, and depict the complex molecular mechanisms proposed to be involved in glucotoxicity. Finally, from a more translational perspective, different therapeutic strategies targeting hyperglycaemia-mediated molecular mechanisms will be detailed

Sucralose and Cardiometabolic Health: Current Understanding from Receptors to Clinical Investigations

International audienceThe excess consumption of added sugar is consistently found to be associated with weight gain, and a higher risk of type 2 diabetes mellitus, coronary heart disease, and stroke. In an effort to reduce the risk of cardiometabolic disease, sugar is frequently replaced by low- and null-calorie sweeteners (LCSs). Alarmingly, though, emerging evidence indicates that the consumption of LCSs is associated with an increase in cardiovascular mortality risk that is amplified in those who are overweight or obese. Sucralose, a null-caloric high-intensity sweetener, is the most commonly used LCS worldwide, which is regularly consumed by healthy individuals and patients with metabolic disease. To explore a potential causal role for sucralose in increased cardiovascular risk, this present review summarizes the preclinical and clinical data from current research detailing the effects of sucralose on systems controlling food intake, glucose homeostasis, and gut microbiota

Antioxidant properties of tea blunt ROS-dependent lipogenesis: beneficial effect on hepatic steatosis in a high fat-high sucrose diet NAFLD obese rat model

International audienceOxidative stress could trigger lipid accumulation in liver and thus hepatic steatosis. Tea is able to prevent liver disorders, but a direct link between antioxidant capacities and prevention of steatosis has not been reported yet. We aimed to investigate such relationship in a rat model of high fat-high sucrose diet (HFS)-induced obesity and to explore more deeply the mechanisms in isolated hepatocytes. Wistar rats were divided into a control group (standard diet), an HFS group (high fat-sucrose diet) and an HFS+tea group (HFS diet with ad-libitum access to tea drink). Body weight, fat mass, glycemic parameters in blood, lipid and oxidative stress parameters in blood and liver were measured in each group after 14 weeks. Isolated hepatocytes were treated with the reactive oxygen species (ROS) inducer t-BHP in the presence or not of antioxidants (tempol or tea), and superoxide anion production and lipid accumulation were measured using specific fluorescent probes. We reported that the HFS diet highly increased hepatic lipids content, while tea consumption attenuated steatosis and improved the oxidative status (decrease in hepatic oxidative stress, increase in plasma total antioxidant capacity). The role of antioxidant properties of tea in such phenomenon was confirmed in primary cultured rat hepatocytes. Indeed, the increase of mitochondrial ROS production with t-BHP resulted in lipid accumulation in hepatocytes (positive linear regression), and antioxidants (tempol or tea) normalized both. We reported that the antioxidant properties of tea protect rats from an obesogenic HFS diet-induced hepatic steatosis by counteracting the ROS-dependent lipogenesis

Vascular endothelial function masks increased sympathetic vasopressor activity in rats with metabolic syndrome

International audienceSympathetic hyperactivation, a common feature of obesity and metabolic syndrome, is a key trigger of hypertension. However, some obese subjects with autonomic imbalance present a dissociation between sympathetic activity-mediated vasoconstriction and increased blood pressure. Here, we aimed to determine in a rat model of metabolic syndrome whether the endothelium endothelial nitric oxide (NO) synthase (eNOS)-NO pathway contributes to counteract the vasopressor effect of the sympathetic system. Rats were fed a high-fat and high-sucrose (HFS) diet for 15 wk. Sympathovagal balance was evaluated by spectral analysis of heart rate variability and plasmatic catecholamine measurements. Blood pressure was measured in the presence or absence of N-nitro-l-arginine methyl ester (l-NAME) to inhibit the contribution of eNOS. Vascular reactivity was assessed on isolated aortic rings in response to α1-adrenergic agonist. The HFS diet increased sympathetic tone, which is characterized by a higher low on the high-frequency spectral power ratio and a higher plasmatic concentration of epinephrine. Despite this, no change in blood pressure was observed. Interestingly, HFS rats exhibited vascular hyporeactivity (-23.6%) to α1-adrenergic receptor stimulation that was abolished by endothelial removal or eNOS inhibition (l-NAME). In addition, eNOS phosphorylation (Ser1177) was increased in response to phenylephrine in HFS rats only. Accordingly, eNOS inhibition in vivo revealed higher blood pressure in HFS rats compared with control rats (147 vs. 126 mmHg for mean blood pressure, respectively). Restrain of adrenergic vasopressor action by endothelium eNOS is increased in HFS rats and contributes to maintained blood pressure in the physiological range. NEW & NOTEWORTHY Despite the fact that prohypertensive sympathetic nervous system activity is markedly increased in rats with early metabolic syndrome, they present with normal blood pressure. These observations appear to be explained by increased endothelial nitric oxide synthase response to adrenergic stimulation, which results in vascular hyporeactivity to α-adrenergic stimulation, and therefore blood pressure is preserved in the physiological range. Listen to this article's corresponding podcast at http://www.physiology.org.proxy.insermbiblio.inist.fr/doi/10.1152/ajpheart.00217.2017

Exercise does not activate the β3 adrenergic receptor–eNOS pathway, but reduces inducible NOS expression to protect the heart of obese diabetic mice

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