Contact inhibition of locomotion (CIL) is a multifaceted process that causes many cell types to repel each other upon collision. During development, this seemingly uncoordinated reaction is a critical driver of cellular dispersion within embryonic tissues. Here, we show that Drosophila hemocytes require a precisely orchestrated CIL response for their developmental dispersal. Hemocyte collision ...

0957-4174/$ see front matter 2012 Elsevier Ltd. A http://dx.doi.org/10.1016/j.eswa.2012.07.076 ⇑ Corresponding author. E-mail address: [email protected] (D. Petković) It is known that robotic manipulators are highly nonlinear systems, and an accurate mathematical model is difficult to obtain, thus making it difficult to analyze with conventional analytical methods. Here, a novel design of an ...

In this work, we present an extension to a linear Model Predictive Control (MPC) scheme that plans external contact forces for the robot when given multiple contact locations and their corresponding friction cone. To accomplish this we set up a two step optimization problem. In the first optimization, we compute the Center of Mass (CoM) trajectory, foot step locations, and introduce slack varia...

Experimental techniques that utilize atomic force microscopy are routinely used to examine tribological properties of tip–sample interactions. While analysis of data obtained with these methods provides values for macroscale properties, such as interfacial shear strength, understanding nanoscale properties, such as contact radius, requires an atomic-scale approach. Molecular dynamics simulation...

Knee osteoarthritis (OA) commonly occurs in the medial compartment of the knee and has been linked to overloading of the medial articular cartilage. Gait modification represents a non-invasive treatment strategy for reducing medial compartment knee force. The purpose of this study was to evaluate the effectiveness of a variety of gait modifications that were expected to alter medial contact for...

Frogs are well-known to capture elusive prey with their protrusible and adhesive tongues. However, the adhesive performance of frog tongues and the mechanism of the contact formation with the prey item remain unknown. Here we measured for the first time adhesive forces and tongue contact areas in living individuals of a horned frog (Ceratophrys sp.) against glass. We found that Ceratophrys sp. ...

Carbon nanotubes are usually imaged with the atomic force microscope (AFM) in non-contact mode. However, in many applications, such as mechanical manipulation or elasticity measurements, contact mode is used. The forces affecting the nanotube are then considerable and not fully understood. In this work lateral forces were measured during contact mode imaging with an AFM across a carbon nanotube...

This paper presents a simple and fast solution to the problem of finding the time variation of n contact forces that keep an object under equilibrium while one of the n contact forces is removed/added from/to the grasp. The object is under a constant perturbation force, like for instance its own weight. It is assumed no acceleration of the object during the regrasp operation, as well as the kno...

Small knee flexion angles at initial contact and large ground reaction forces during landing have been identified as risk factors for non-contact anterior cruciate ligament injuries that are common in sports. This study investigated the effects of knee extension constraint on knee flexion angle and ground reaction forces for patients who were 4-6 months post ACL reconstruction surgery, and also...

Impulsive forces are more efficient than dynamic and static forces, and are used to achieve everyday tasks that would be difficult or impossible using the latter two types of forces. Yet, impact is rarely used in robotic manipulation due to difficulties in modeling, planning, and control. This paper studies the problem of batting a free flying object to a target location, with a focus on comput...