Bridging the Titin Gap: The muscle protein titin is a molecular spring that has been extensively studied by single-molecule unfolding experiments and by molecular simulation. However, experimental and simulated unfolding could not be compared directly because they differ by orders of magnitude in pulling velocity. Rico et al. (p 741 ) developed high-speed force spectroscopy to pull titin molecules at speeds that reach the lower limits of molecular dynamics simulations. Bridging the gap between simulation and experiment clarified the mechanism of conformational changes in titin.

Manipulating in the micro- or even nano world still poses a great challenge to robotics. Conventional (stationary) systems suffer from drawbacks regarding integration into process supervision and multi-robot approaches, which become highly relevant to fight scaling effects. This paper describes work currently being carried out which aims to make automated manipulation of micrometer-scaled objects possible by robots with nanometer precision. The goal is to establish a small cluster of (up to five) micro robots equipped with on-board electronics, sensors and wireless power supply. Power autonomy has been reached using inductive energy transmission from an external wireless power supply system or a battery based system. Electronics requirements are fulfilled in the electronic module with the full custom integrated circuit design for the robot locomotion control and the closed loop force control for AFM tool in cell manipulation applications. The maximum velocity obtained i s about 0.4 mm/s with a saw tooth voltage signals of 20Vpp and 2500 Hz. In order to keep a AFM tool on micro-robot a specific tip with integrated piezoresistance, instead of the classical laser beam methodology, is validated for force measurement

The concept and design of a power-conditioning circuit for an autonomous low-power system-in-package (SiP) is presented in this paper. The SiP's main power source is based on the use of micropiezoelectric generators. The electrical model of the power source, which has been obtained based on experimental measurements and implemented on Cadence Analog Artist's Spectre simulation environment, is explained. The model has been used to simulate the power source with the power-conditioning electronics over the entire design process. Finally, the simulated and experimental results of the developed integrated power circuits, which are formed by a rectifier and a low-power bandgap reference voltage source to define the threshold voltage for the closed-loop regulation process, are also shown. These circuits have been designed using a commercial 0.13-mum technology from ST Microelectronics through the multi-projects circuits (CMP) techniques of informatics and microelectronics for integrated systems architecture (TIMA) service.

In this paper, we introduce a cooperative medium access control (MAC) protocol, named cooperative energy harvesting (CEH)-MAC, that adapts its operation to the energy harvesting (EH) conditions in wireless body area networks (WBANs). In particular, the proposed protocol exploits the EH information in order to set an idle time that allows the relay nodes to charge their batteries and complete the cooperation phase successfully. Extensive simulations have shown that CEH-MAC significantly improves the network performance in terms of throughput, delay and energy efficiency compared to the cooperative operation of the baseline IEEE 802.15.6 standard.

One way to enhance the efficiency of energy harvesting systems is complex conjugate impedance matching of its electrical impedance. In Piezoelectric energy Harvesting systems the match is done to increment the energy flows from a vibration energy source to an energy storage electrical circuit. In this article, we compare the power generated using the modulus impedance matching with the power generated using the complex conjugate impedance matching. We present the power ratio between both types of matching methods. The novelty of this article consists of a piezoelectric transducer completely adapted with a complex conjugate impedance match. The theory developed is validated on a commercial piezoelectric transducer QP40w from Midé Technology. The transducer model is first identified by means of a system identification step based on a novel two-port Lumped-Electromechanical Model. The QP40w is complex conjugate matched at its fourth resonant mode increasing the generated power by up to 20% more compared with the modulus match.