Mapping densely distributed membrane receptors in blood platelets with expansion microscopy

Interrogating small platelets and their densely packed, highly abundant receptor landscape is key to understand platelet clotting. Blot clots can save lives when stopping blood loss after an injury, but also kill when blocking a major vessel. The highly abundant and densely distributed GPIIb/IIIa receptors are one reason why the underlying key distributions and interactions, in particular the relevance of integrin clustering, are not fully understood. Such dense receptor scenarios are difficult to assess even by super-resolution fluorescence microscopy. Here, we quantify various receptor interactions, and demonstrate that expansion microscopy can pinpoint such challenging interactions where conventional methods fail in such dense 3D scenarios with highly abundant receptors. We successfully combine dual-color expansion and confocal microscopy with colocalization analysis and assess platelet receptor organization without the need of a super-resolution microscope. We reveal that GPIIb/IIIa receptors are organized in pre-formed clusters in resting platelets – a pattern that orchestrates platelet clotting. We show that 4x expansion is most straight-forward for platelet imaging, while 10x expansion provides highest precision which turned out to be absolutely necessary for the most difficult of the scenarios described here.Graphical AbstractNonstandard Abbreviations and AcronymsGPIX: glycoprotein IXExM: expansion microscopyKey PointsMapping of the very dense, highly abundant platelet receptor landscape requires 10x Expansion MicroscopyExM reveals that GPIIb/IIIa receptors are organized in pre-formed clusters in resting platelets.

3D Exploration and Navigation with Optimal-RRT Planners for Ground Robots in Indoor Incidents

Navigation and exploration in 3D environments is still a challenging task for autonomous robots that move on the ground. Robots for Search and Rescue missions must deal with unstructured and very complex scenarios. This paper presents a path planning system for navigation and exploration of ground robots in such situations. We use (unordered) point clouds as the main sensory input without building any explicit representation of the environment from them. These 3D points are employed as space samples by an Optimal-RRTplanner (RRT * ) to compute safe and efficient paths. The use of an objective function for path construction and the natural exploratory behaviour of the RRT * planner make it appropriate for the tasks. The approach is evaluated in different simulations showing the viability of autonomous navigation and exploration in complex 3D scenarios.

An approach for real-time motion planning of an inchworm robot in complex steel bridge environments

SUMMARYPath planning can be difficult and time consuming for inchworm robots especially when operating in complex 3D environments such as steel bridges. Confined areas may prevent a robot from extensively searching the environment by limiting its mobility. An approach for real-time path planning is presented. This approach first uses the concept of line-of-sight (LoS) to find waypoints from the start pose to the end node. It then plans smooth, collision-free motion for a robot to move between waypoints using a 3D-F2algorithm. Extensive simulations and experiments are conducted in 2D and 3D scenarios to verify the approach.

Creating 3D Scenarios with OGRE Creativity Labs

Currently, there are several languages and tools to provide the creation of virtual scenarios. However, the existing approaches are not intuitive and require further knowledge of the user. This paper introduces an application to allow the creation of virtual scenarios with high graphical quality called OGRE Creativity Labs (OGRE-CL). OGRE-CL provides OGRE application developers with a graphical environment for the rapid prototyping of 3D scenarios, and the subsequent automatic generation of the respective OGRE code. With this tool, developers can have their development time optimized since they rather focus on the codification of the dynamics and strategies of the application being developed without spending much time with the design of its graphical components.

Interfaces for 3D Flight Path Visualization

Increased use of unmanned aerial vehicles on the battlefield is driving a transition of human operators into supervisory roles. In these roles, operators will have access to mission data and they will be required to make rapid decisions based on criteria, prior experience, and instincts. To facilitate rapid decisions, an interface must provide information in a format that operators can readily understand. A study was performed to investigate an operator’s ability to rapidly understand flight path data presented in either top-down 2D or perspective 3D. Additionally, the study aimed to explore the benefits of interactivity when observing the 3D scenarios. It was found that participants in the 3D group with automatic camera movement were not more accurate but were faster than participants who saw a top-down 2D view or a 3D view with manual camera control. This suggests that there may be benefits to a 3D interface for displaying three-dimensional path data. It also confirms that providing an interactive interface will not necessarily lead to higher performance, as the user may not use it efficiently.