Frédéric Lebeau

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

BackgroundMicrobial 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.ResultsA 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.ConclusionThis 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.

Modeling the hygrothermal behavior of biobased construction materials

Materials with high moisture exchange capacity may have a strong impact on indoor climate conditions as well as building energy performance. Crop-based materials, characterized by their high porosity and hygroscopicity, belong to this category. Modeling their hygrothermal behavior accurately is thus particularly relevant for appropriate building design. A COMSOL Multiphysics transient heat air and moisture model is developed in this article to simulate moisture exchange between a lime–hemp concrete block and surrounding air during a Moisture Buffer Value evaluation test. Results are then compared with the validated heat air and moisture software using performance criteria showing a slight preference for both moisture exchanges and latent heat effect characterization. It offers yet additional advantages in terms of flexibility and transparency as well as further evolution potential.

Measurements of the horizontal sprayer boom movements by sensor data fusion

A study investigated the horizontal movements of trailed sprayer booms with the aim of distinguishing their yaw and jolt motions as well as their deformations. Two vehicles were equipped with a radar speed sensor and a three-axis dynamic measurement unit, while each boom was instrumented with ultrasonic sensors and accelerometers. Sensor fusion was used to extract yaw, jolt and deformation speeds by assuming that the motion of any point of the boom is equal to the superimposition of complementary high and low-frequency motions, delimited by a cut-off frequency, estimated on the basis of laboratory trials. Tests performed on trailed sprayers equipped with 22 and 24 m boom lengths, on different soils, indicated that yaw, jolting and deformation, respectively, occurred near 0.3, 2 and 1 Hz. Velocity variations relative to the forward speed of the vehicle were lower than 0.57 m/s and were reached at a speed of 3.5 m/s (12.7 km/h). Ground deposit, roughly estimated as proportional to the inverse of the speed, exhibited coefficients of variation between 4 and 6% for all tests.

Impact of the horizontal movements of a sprayer boom on the longitudinal spray distribution in field conditions

Abstract The influence of horizontal sprayer boom movements on the longitudinal distribution of the sprayed product was investigated in field and laboratory conditions. The boom movements of a sprayer were measured in the field using a specially designed measurement chain, and the resulting ground distribution was estimated by spraying a dye (Nigrosine) on large sheets of wallpaper and using image analysis to compute the spray coverage. The horizontal movements, identical to those measured in the field, were applied to a laboratory boom part moving on horizontal rails, in the absence of wind. For the three tested situations, the longitudinal coefficients of variation (CV) of the spray coverage were very close in the field (8.81%, 6.9%, 10.9%) and in the laboratory (9.17%, 8.17%, 10.96%). This indicates that horizontal movements were the main source of spray deposit variations, even if other factors such as vertical movements or wind may have an influence. The mean ratio RCV between the CV of the horizontal movements and the spray coverage was estimated. In addition, the amplitude of the boom movements was investigated in a large range of situations (five different sprayers, three different crops). On basis of the measured movements and the computed RCV, the variability of the longitudinal spray distribution due to horizontal movements was estimated at between 3.5% and 5.2%.

Web-based cattle behavior service for researchers based on the smartphone inertial central

Abstract Smartphones, particularly iPhones, can be relevant instruments for researchers in animal behavior because they are readily available on the planet, contain many sensors and require no hardware development. They are equipped with high performance inertial measurement units (IMU) and absolute positioning systems analyzing users’ movements, but they can easily be diverted to analyze likewise the behaviors of domestic animals such as cattle. The study of animal behavior using smartphones requires the storage of many high frequency variables from a large number of individuals and their processing through various relevant variables combinations for modeling and decision-making. Transferring, storing, treating and sharing such an amount of data is a big challenge. In this paper, a lambda cloud architecture and a scientific sharing platform used to archive and process high-frequency data are proposed. An application to the study of cattle behavior on pasture on the basis of the data recorded with the IMU of iPhones 4S is exemplified. The package comes also with a web interface to encode the actual behavior observed on videos and to synchronize observations with the sensor signals. Finally, the use of fog computing on the iPhone reduced by 42% on average the size of the raw data by eliminating redundancies.

Web Monitoring of Bee Health for Researchers and Beekeepers Based on the Internet of Things

Abstract The Colony Collapse Disorder (CCD) also entitled ‘Colony Loss’ has a significant impact on the biodiversity, on the pollination of crops and on the profitability. The Internet of Things associated with cloud computing offers possibilities to collect and treat a wide range of data to monitor and follow the health status of the colon. The surveillance of the animals’ pollination by collecting data at large scale is an important issue in order to ensure their survival and pollination, which is mandatory for food production. Moreover, new network technologies like Low Power Wide Area (LPWAN) or 3GPP protocols and the appearance on the market easily programmable nodes allow to create, at low-cost, sensors and effectors for the Internet of Things. In this paper, we propose a technical solution easily replicable, based on accurate and affordable sensors and a cloud architecture to monitor and follow bees’ behavior. This solution provides a platform for researchers to better understand and measure the impacts factors which lead to the mass extinction of bees. The suggested model is also a digital and useful tool for beekeepers to better follow up with their beehives. It helps regularly inspect their hives to check the health of the colony. The massive collection of data opens new research for a better understanding of factors that influence the life of bees.

Monitoring System Using Internet of Things For Potential Landslides

Abstract The North-Western RIF of Morocco is considered as one of the most mountainous zone in the Middle East and North Africa. This area is more serious in the corridor faults region, where the recent reactivation of those tectonic layering may greatly contribute to the triggering of landslides. The consequences of this phenomenon can be enormous property damage and human casualties. Furthermore, this disaster can disrupt progress and destroy developmental efforts of government, and often pushing nations back by many years. In our previous works of Tetouan-Ras-Mazari region, we identified the areas that are prone to landslides by different methods like Weights of Evidence (WofE) and Logistic Regression (LR). In fact, these zones are built and susceptible. Undoubtedly, the challenge to save human lives is vital. For this reason, we develop a robust monitoring model as part of an alert system to evacuate populations in case of imminent danger risks. This model is ground-based remote monitoring system consist of more than just field sensors; they employ data acquisition units to record sensor measurements, automated data processing, and display of current conditions usually via the Internet of Things (IoT). To sum up, this paper outlines a new approach of monitoring to detect when hillslopes are primed for sliding and can provide early indications of rapid and catastrophic movement. It reports also continuous information from up-to-the-minute or real-time monitoring, provides prompt notification of landslide activities, advances our understanding of landslide behaviors, and enables more effective engineering and planning efforts.

Applying Control Volume Finite Element for Modelling Direct Injection Boom Spraying Flow

Assessment of injection lag transport and uniformity of direct injection boom sprayer is an important issue for successful variable rate spraying technology. To estimate the boom lag transport and pressure loss, a numerical model is formulated on the basis of fluid hydrodynamic conservation equations. The software is implemented in visual basic. To solve the pressure – velocities equations, control volume finite element method (CV) is used to delimit elementary volumes of the boom. Linearization of the conservation laws is ensured by considering discrete form of the equations and calculating velocity and pressure step by step throughout the whole boom. The flow behaviour is simulated into a boom section divided into N elementary volumes, each of them including one nozzle.