Path planning for flexible needle based on both insertion mechanism kinematics and needle bending model.

Objective: Due to the limited operating space in the magnetic resonance (MR) environment, there is coupled motion in the insertion mechanism, which not only reduces the flexibility of the robot but also challenges the insertion path planning. Meanwhile, the path planning is also restricted by the bending rule of the flexible needle, thus the bending model of the needle is also essentially built.

Approach: This paper proposes a path planner for the flexible needle based on both the coupled motion kinematics of the insertion robot and the bending model of the flexible needle.

Regulation of Cytosolic pH: The Contributions of Plant Plasma Membrane H-ATPases and Multiple Transporters.

Cytosolic pH homeostasis is a precondition for the normal growth and stress responses in plants, and H flux across the plasma membrane is essential for cytoplasmic pH control. Hence, this review focuses on seven types of proteins that possess direct H transport activity, namely, H-ATPase, NHX, CHX, AMT, NRT, PHT, and KT/HAK/KUP, to summarize their plasma-membrane-located family members, the effect of corresponding gene knockout and/or overexpression on cytosolic pH, the H transport pathway, and their functional regulation by the extracellular/cytosolic pH. In general, H-ATPases mediate H extrusion, whereas most members of other six proteins mediate H influx, thus contributing to cytosolic pH homeostasis by directly modulating H flux across the plasma membrane.