Hybrid Regional Aircraft: A Comparative Review of New Potentials Enabled by Electric Power

This article assesses the benefits of hybridization within the regional aircraft scale using a conventional twin-turbo propeller aircraft as reference. For a fair comparison, this reference aircraft was designed assuming a 2035 technology level. The propulsion system of the reference aircraft is analyzed along the mission and the phases of flight with low efficiencies are highlighted. Then the potential benefits of new power management through the use of secondary power generation systems but also through the variation of the size of prime movers are presented and discussed. In particular, the effect of the gas turbine size on its efficiency is studied. Finally, the article focuses on aerodynamic improvements enabled by new propeller or fan integrations and the associated concepts such as differential thrust, blown wing and boundary layer ingestion. For each topic, simplified analyses provide estimated potential of energy saving. These results can be used as indicators for selecting the most promising hybrid architecture concepts for a regional aircraft

Hybrid Propulsion for Regional Aircraft: a Comparative Analysis based on Energy Efficiency

This article assesses the potential benefits of transient energy storage for a hybrid regional aircraft. The mission profile of a reference aircraft is analyzed according to energetic intermittence and the results are compared to typical figures for cars, trains, and ships. Also, the opportunity of recovering energy in descent and during landing is studied. This article shows that energy saving potential brought by transient energy storage is much smaller than for ground-based transportation. In addition, energy recovering does not bring benefit on a hybrid aircraft in normal operation. Nevertheless, the best energy management strategies in descent are highlighted and the use of a hybrid propulsion system in this phase shows significant potential energy savings. Finally, the article addresses other strategies enabled by hybrid propulsion to improve the aircraft energy efficiency

Isolation and Comparative Transcriptome Analysis of Human Fetal and iPSC-Derived Cone Photoreceptor Cells.

Loss of cone photoreceptors, crucial for daylight vision, has the greatest impact on sight in retinal degeneration. Transplantation of stem cell-derived L/M-opsin cones, which form 90% of the human cone population, could provide a feasible therapy to restore vision. However, transcriptomic similarities between fetal and stem cell-derived cones remain to be defined, in addition to development of cone cell purification strategies. Here, we report an analysis of the human L/M-opsin cone photoreceptor transcriptome using an AAV2/9.pR2.1:GFP reporter. This led to the identification of a cone-enriched gene signature, which we used to demonstrate similar gene expression between fetal and stem cell-derived cones. We then defined a cluster of differentiation marker combination that, when used for cell sorting, significantly enriches for cone photoreceptors from the fetal retina and stem cell-derived retinal organoids, respectively. These data may facilitate more efficient isolation of human stem cell-derived cones for use in clinical transplantation studies

Elucidating the role of brain manganese in health and disease using a patient-derived neuronal model

Introduction: Manganese (Mn) is an essential trace metal, crucial for normal neuronal cell function. Acquired and genetic disorders leading to Mn imbalance in humans can result in a broad spectrum of phenotypes, including parkinsonism-dystonia and neurodevelopmental delay/regression. Bi-allelic mutations in genes encoding Mn transporters ZIP14, ZIP8 and ZnT10 have been identified in patients with Mn dyshomeostasis, and are associated with progressive, often debilitating disorders. Little is known about the molecular mechanisms underlying Mn dysregulation and neurotoxicity, and there are currently no effective treatments. Aim: The aim of this thesis is to identify disease-specific phenotypes and decipher the molecular mechanisms associated with Mn dyshomeostasis in a patient-derived midbrain dopaminergic (mDA) neuronal model. Methods: Using age-matched and CRISPR-Cas9 generated controls and patient-derived induced pluripotent stem cells, I have developed a humanized mDA neuronal model of the three inherited Mn transportopathies. I have used a range of molecular, cellular, and transcriptomic approaches to investigate the physiological role and pathophysiological sequelae of Mn in health and disease. Results: Key results show disease-specific dysregulation of Mn and other metals. Mn dysregulation also leads to an increase in cellular stress through activation of the SAPK/JNK pathway, which leads to caspase-3 activation and is suggestive of increased apoptosis. Assessment of mitochondrial function highlights dysregulation of mitochondrial OXPHOS complexes, with abnormal gene and protein expression as well as impaired enzymatic activity, defects in mitochondrial membrane potential, and ATP production. Broader bulk RNA-sequencing analysis confirms the observed disease-specific mitochondrial dysregulation as well as dysregulation of pathways associated with collagen metabolism, synaptic function, oxidative stress, and cell death. Bulk-RNA sequencing findings are further confirmed by calcium imaging, Seahorse assay, and an endocytic uptake assay. Moreover, transcriptomic analysis highlights common dysregulated pathways between these Mn transportopathies and other similar neurodegenerative disorders such as Parkinson’s and Alzheimer’s disease

Optimization of primary flight control actuation system using parametric sizing models of actuators, power electronics and structural analysis

International audienceThe design of aerospace actuation systems is an exciting challenge in terms of integration and performance requirements, engineering specializations, technological limits and numerical tools. The investigation of future flight control actuation system technologies and architectures has to evaluate the impact of new concepts on each subsystem in a tightly coupled manner. This paper presents an investigation of the effect of control surface splitting on an aileron using a Multidisciplinary System Design Optimization technique. The investigation is then extended to a primary flight control actuation system. Parametric sizing models help determine geometries and performances of rotary on hinge electromechanical actuator, associated power electronics and structural analysis. Promising preliminary results about effects of control surface splitting on aileron and on primary flight control surface layout are presented

Hybrid Regional Aircraft: A Comparative Review of New Potentials Enabled by Electric Power

International audienceThis article assesses the benefits of hybridization within the regional aircraft scale using a conventional twin-turbo propeller aircraft as reference. For a fair comparison, this reference aircraft was designed assuming a 2035 technology level. The propulsion system of the reference aircraft is analyzed along the mission and the phases of flight with low efficiencies are highlighted. Then the potential benefits of new power management through the use of secondary power generation systems but also through the variation of the size of prime movers are presented and discussed. In particular, the effect of the gas turbine size on its efficiency is studied. Finally, the article focuses on aerodynamic improvements enabled by new propeller or fan integrations and the associated concepts such as differential thrust, blown wing and boundary layer ingestion. For each topic, simplified analyses provide estimated potential of energy saving. These results can be used as indicators for selecting the most promising hybrid architecture concepts for a regional aircraft

Hybrid Regional Aircraft: A Comparative Review of New Potentials Enabled by Electric Power

International audienceThis article assesses the benefits of hybridization within the regional aircraft scale using a conventional twin-turbo propeller aircraft as reference. For a fair comparison, this reference aircraft was designed assuming a 2035 technology level. The propulsion system of the reference aircraft is analyzed along the mission and the phases of flight with low efficiencies are highlighted. Then the potential benefits of new power management through the use of secondary power generation systems but also through the variation of the size of prime movers are presented and discussed. In particular, the effect of the gas turbine size on its efficiency is studied. Finally, the article focuses on aerodynamic improvements enabled by new propeller or fan integrations and the associated concepts such as differential thrust, blown wing and boundary layer ingestion. For each topic, simplified analyses provide estimated potential of energy saving. These results can be used as indicators for selecting the most promising hybrid architecture concepts for a regional aircraft

Isolation of human photoreceptor precursors via a cell surface marker panel from stem cell-derived retinal organoids and fetal retinae

Loss of photoreceptor cells due to retinal degeneration is one of the main causes of blindness in the developed world. Although there is currently no effective treatment, cell replacement therapy using stem-cell-derived photoreceptor cells may be a feasible future treatment option. In order to ensure safety and efficacy of this approach, robust cell isolation and purification protocols must be developed. To this end, we previously developed a biomarker panel for the isolation of mouse photoreceptor precursors from the developing mouse retina and mouse embryonic stem cell cultures. In the current study we applied this approach to the human pluripotent stem cell (hPSC) system, and identified novel biomarker combinations that can be leveraged for the isolation of human photoreceptors. Human retinal samples and hPSC-derived retinal organoid cultures were screened against 242 human monoclonal antibodies using a high through-put flow cytometry approach. We identified 46 biomarkers with significant expression levels in the human retina and hPSC differentiation cultures. Human retinal cell samples, either from fetal tissue or derived from embryonic and induced pluripotent stem cell cultures, were fluorescence-activated cell sorted (FACS) using selected candidate biomarkers that showed expression in discrete cell populations. Enrichment for photoreceptors and exclusion of mitotically active cells was demonstrated by immunocytochemical analysis with photoreceptor-specific antibodies and Ki-67. We established a biomarker combination, which enables the robust purification of viable human photoreceptors from both human retinae and hPSC-derived organoid cultures