Measuring spore settling velocity for an improved assessment of dispersal rates in mosses.

BACKGROUND AND AIMS: The settling velocity of diaspores is a key parameter for the measurement of dispersal ability in wind-dispersed plants and one of the most relevant parameters in explicit dispersal models, but remains largely undocumented in bryophytes. The settling velocities of moss spores were measured and it was determined whether settling velocities can be derived from spore diameter using Stokes' Law or if specific traits of spore ornamentation cause departures from theoretical expectations. METHODS: A fall tower design combined with a high-speed camera was used to document spore settling velocities in nine moss species selected to cover the range of spore diameters within the group. Linear mixed effect models were employed to determine whether settling velocity can be predicted from spore diameter, taking specific variation in shape and surface roughness into account. KEY RESULTS: Average settling velocity of moss spores ranged from 0·49 to 8·52 cm s(-1) There was a significant positive relationship between spore settling velocity and size, but the inclusion of variables of shape and texture of spores in the best-fit models provides evidence for their role in shaping spore settling velocities. CONCLUSIONS: Settling velocities in mosses can significantly depart from expectations derived from Stokes' Law. We suggest that variation in spore shape and ornamentation affects the balance between density and drag, and results in different dispersal capacities, which may be correlated with different life-history traits or ecological requirements. Further studies on spore ultrastructure would be necessary to determine the role of complex spore ornamentation patterns in the drag-to-mass ratio and ultimately identify what is the still poorly understood function of the striking and highly variable ornamentation patterns of the perine layer on moss spores.

A low-cost, multiplexable, automated flow cytometry procedure for the characterization of microbial stress dynamics in bioreactors.

BACKGROUND: Microbial cell population heterogeneity is now recognized as a major source of issues in the development and optimization of bioprocesses. Even if single cell technologies are available for the study of microbial population heterogeneity, only a few of these methods are available in order to study the dynamics of segregation directly in bioreactors. In this context, specific interfaces have been developed in order to connect a flow cytometer directly to a bioreactor for automated analyses. In this work, we propose a simplified version of such an interface and demonstrate its usefulness for multiplexed experiments. RESULTS: A low-cost automated flow cytometer has been used in order to monitor the synthesis of a destabilized Green Fluorescent Protein (GFP) under the regulation of the fis promoter and propidium iodide (PI) uptake. The results obtained showed that the dynamics of GFP synthesis are complex and can be attributed to a complex set of biological parameters, i.e. on the one hand the release of protein into the extracellular medium and its uptake modifying the activity of the fis promoter, and on the other hand the stability of the GFP molecule itself, which can be attributed to the protease content and energy status of the cells. In this respect, multiplexed experiments have shown a correlation between heat shock and ATP content and the stability of the reporter molecule. CONCLUSION: This work demonstrates that a simplified version of on-line FC can be used at the process level or in a multiplexed version to investigate the dynamics of complex physiological mechanisms. In this respect, the determination of new on-line parameters derived from automated FC is of primary importance in order to fully integrate the power of FC in dedicated feedback control loops.

Lipid-lowering treatment up to one year after acute coronary syndrome: guidance from a French expert panel for the implementation of guidelines in practice.

The management of patients with coronary artery disease (CAD) is complex, especially after they have been discharged from hospital after an acute coronary syndrome (ACS), because each patient may have numerous healthcare providers, and follow-up after discharge may be disjointed, or even incomplete. During follow-up after ACS, few patients have treatment intensification; rather, there is actually a major tendency towards reductions in treatment intensity, to the potential detriment of outcomes. We present here guidance from a French expert panel for the optimal management of lipid-lowering therapy up to 1 year after ACS. A French expert panel provides a practical guide for the implementation of guidelines for the management of post-ACS patients in routine practice, from hospital discharge up to one year after the index event, focusing in particular on the achievement of target LDL cholesterol (LDL-C) levels. We discuss the early follow-up (up to 6 months after discharge) and review the lipid-lowering treatment strategies that should be implemented. We discuss the evidence underpinning the prescription of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors as well as recent evidence about icosapent ethyl. This review should facilitate implementation of a clear and effective lipid-lowering strategy for all patients after ACS. The panel recommends early use of high-intensity statins, in combination with ezetimibe for patients with LDL-c above 100 mg/dL at baseline. PCSK9i should be rapidly added during the first 3 months in high-risk diabetic patients with residual LDL-C above 70 mg/dL (with further benefit for those with residual LDL-C above ≥100 mg/dL) despite maximal tolerated dose statin and ezetimibe, patients with recent ACS, and patients with recurrent ischemic events under optimal medical therapy, multivessel coronary disease (MVD) and/or polyvascular disease (PVD), especially symptomatic PAD diabetic patients. Concerning icosapent ethyl (EPA), this drug should be introduced in patients ≥45 years of age with clinical atherosclerotic cardiovascular disease (ASCVD) or already on high-intensity or maximally tolerated statin therapy or with fasting triglycerides 135-499 mg/dL (with or without ezetimibe). Lipid-lowering treatment should be introduced as early as possible to obtain a rapid and profound decrease of LDL-c from baseline, using high-intensity statins (atorvastatin or rosuvastatin) and ezetimibe in fixed combination before discharge. Then, the strategy should be rapidly intensified by adding a PCSK9 inhibitor if the patient does not reach LDL-c levels below 55 mg/dL. We advocate this intensive strategy, which has demonstrated a further reduction in ischemic events, without safety concerns, even for patients who reach very low LDL-cholesterol levels. This approach, comprising few therapeutic steps, aims to rapidly reach LDL-c goals, improve patient compliance, and is an efficient method to fight therapeutic inertia, which remains a major issue.

French expert group proposal for lipid-lowering therapy in the first 3 months after acute myocardial infarction.

In patients admitted for acute myocardial infarction (MI), it has been demonstrated that reducing LDL cholesterol (LDL-c) is associated with a reduction in major adverse cardiovascular events. We describe a consensual proposal made by a French group of experts for lipid-lowering therapy at the acute phase of acute myocardial infarction. A group of French experts comprising cardiologists, lipidologists and general practitioners prepared a proposal for a lipid-lowering strategy with a view to optimizing LDL-c levels in patients hospitalized for myocardial infarction. We describe a strategy for the use of statins, ezetimibe and and/or proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors, with a view to reaching target LDL-c levels as early as possible. This approach, which is currently feasible in France, could considerably improve lipid management in patients after ACS, thanks to its simplicity, rapidity and the magnitude of the decrease in LDL-c that it achieves.

Image analysis of shatter and pinning events on hard-to-wet leaf surfaces by drops containing surfactant.

BACKGROUND: A key challenge for developing computer models of spray retention by plants is to accurately predict how spray drops behave when impacting leaf surfaces. One poorly understood outcome occurs when drops bounce or shatter on impact but leave behind a proportion of the liquid on the surface (designated as pinning). This process is studied via impaction experiments with two hard-to-wet leaf surfaces (fat-hen: Chenopodium album and barnyard grass: Echinochloa crus-galli L. P. Beauv) and one hydrophobic artificial surface (Teflon) using three liquid formulations. RESULTS: Drops that impact upon Teflon underwent pinning shatter events via a well-known mechanism referred to as receding breakup. Drops impacting on leaf surfaces did not undergo receding breakup because the liquid rim was not in direct contact with the leaf surface when it broke into secondary droplets. However, pinning did occur on plant surfaces via a different mechanism, especially when using formulations containing a surfactant. CONCLUSION: Newly developed image analysis and methodology has allowed quantification of the volume fraction pinned to surfaces when drops shatter. The addition of surfactant can increase both the probability of pinning and the pinned volume when drops shatter on fat-hen or Teflon. However, the surfactants studied did not substantially improve the probability of pinning on barnyard grass. The difference in behaviour between the two leaf surfaces and the underlying mechanism is worth further study. © 2020 Society of Chemical Industry.

Evaluation of realtime spray drift using RTDrift Gaussian advection-diffusion model.

A spray drift model was developed to deliver real time information to the pesticide applicator. The sprayer is equipped with sensors to deliver real time measurement of operational parameters as spray pressure, boom height, horizontal boom movements and geolocalization. The spray droplet size spectrum as a function of pressure was characterized using PDI measurements. Wind speed and direction were measured using a sprayer mounted 2-D ultrasonic anemometer. For each successive boom position, a diffusion-advection Gaussian tilting plume model is used to compute the spray drift deposits downwind. Drift is computed independently for each droplet classes and each nozzle based on the operating parameters. Field trials were performed on a test plot in various wind conditions. The ground drift was measured for different drift distances using fluorimetry analysis. Results show that drift deposits are mainly affected by wind speed and direction what was correctly accounted for by the model. Short distance drift deposits values were overestimated by the model while long distance drift was underestimated. It appears that this most probably origins from embarked wind speed measurements and diffusion parameter. It is concluded that a treatment of embarked wind speed and diffusion measurement should be used to minimize these errors.