In this paper we describe the hitherto unravelled facts on the interactions of a cold atmospheric plasma with living cells and tissues. A specially designed source, plasma needle, is a low-power discharge, which operates under the threshold of tissue damage. When applied properly, the needle does not cause fatal cell injury which would result in cell death (necrosis). Instead, it allows precise and localized cell removal by means of the so-called cell detachment. In addition, plasma can be used for bacterial disinfection. Because of mild treatment conditions, plasma disinfection can be performed in vivo, e.g. on wounds and dental cavities. Presently, one strives to obtain a better control of the operating device. Therefore, plasma has been characterized using a variety of diagnostics, and a smart system has been designed for the positioning of the device with respect to the treated surface.

No abstract

In this survey we analyse the status quo of gas plasma applications in medical sciences. Plasma is a partly ionized gas, which contains free charge carriers (electrons and ions), active radicals, and excited molecules. So-called nonthermal plasmas are particularly interesting, because they operate at relatively low temperatures and do not inflict thermal damage to nearby objects. In the past two decades nonthermal plasmas have made a revolutionary appearance in solid state processing technology. The recent trends focus on using plasmas in health care, for "processing" of medical equipment and even living tissues. The major goal of tissue treatment with plasmas is nondestructive surgery: controlled, high-precision removal of diseased sections with minimum damage to the organism. Furthermore, plasmas allow fast and efficient bacterial inactivation, which makes them suitable for sterilization of surgical tools and local disinfection of tissues. Much research effort must be undertaken before these techniques will become common in medicine, but it is expected that a novel approach to surgery will emerge from plasma science.

In the study of plasma-surface interactions, a well-defined distance from the surface is desired. In this paper, an innovative method is proposed for using the intrinsic properties of a low-power atmospheric plasma to control this distance. It is proposed that the vicinity of a (even poorly) conducting surface imposes a change in the plasma impedance. This effects the reflection of electrical power, which can easily be measured, and provides a non-contact sensor for the distance between the plasma source and the substrate. For this sensor to work, a low-loss and efficient matching network is designed, such that changes in the reflected power are relatively high. With this high-quality matching network at hand, a characterization of the plasma needle is performed in terms of impedance and related parameters. Although characterization is not essential for the development of the sensor, it contributes to fundamental knowledge about the plasma source. Finally, coherence measurements are performed to determine the performance of the above described sensor in different experimental settings.

Abstract-This paper presents a novel control strategy for real-time controlled restraint systems. Today's restraint systems typically include a number of airbags, and a three-point seat belt with load limiter and pretensioner. In the class of realtime controlled restraint systems, the restraint actuator settings are continuously manipulated during the crash. The control strategy developed here is based on reference management, in which a nonlinear device -a reference governor -is added to a primal closed loop controlled system. This governor determines an optimal setpoint in terms of injury reduction and constraint satisfaction by solving a constrained optimization problem. Prediction of the vehicle motion, required to predict future constraint violation, is included in the design and is based on linear regression of past crash data. Simulation results with a MADYMO model show that a significant injury reduction is possible, without prior knowledge of the crash. Furthermore, it is shown that the algorithms are sufficiently fast to be implemented on-line.