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In this paper, we present a novel microscale “Smart Dust” type system designed to operate in aqueous solutions, with a volume of 200~\mu \textm \,\, \times 100~\mu \textm \,\, \times 35 \mu \textm , called a lablet. The lablet contains a 20Hz low-power clock generator, a sensor, electric actuators, and a simple finite state machine to implement a predefined response to the sensor input. It is designed to be rechargeable and to communicate via local contacts through aqueous solution either between lablets or with a docking station chip. The system operates with supply voltages ranging from 0.3 to 1.8V and is thus suitable to be supplied from a capacitor with decreasing voltage. An input rectifier allows powering the lablet independent of polarity. The average current consumption of the system was measured to be 1.3nA when supplied from a capacitor with an initial voltage of 1.8V. The small system scale allows the investigation of “pourable electronics”, a concept where large quantities of microsystems are deployed within a chemical solution to perform a predefined task. Several lablets have been designed and fabricated in a standard 180nm CMOS process and the electrical functionality has been verified by contacting the lablet electrodes with multiple probe needles. In order to use low voltage energy sources to supply the lablet, a voltage up-converter has been designed which is small enough to fit on the lablet. [ABSTRACT FROM AUTHOR]

The nonlinear mechanics of three-layered microcantilevers under base excitation is investigated numerically. Employing the modified version of the couple stress-based theory, together with the Bernoulli-Euler beam theory, the potential energy of the three-layered microsystem is derived, while accounting for size effects. Obtaining the kinetic energy, the equations of motion in the longitudinal and transverse directions are derived via Hamilton's principle. Application of the inextensibility condition reduces the two equations of motion to one nonlinear integro-partial differential equation for the transverse oscillation, consisting of geometrical and inertial nonlinearities. The nonlinear equation of partial-differential type is reduced to set of equations of ordinary-differential type through use of a weighted-residual method. Solving the resultant set of discretised equations via a continuation technique gives the frequency-amplitude and force-amplitude responses of the microsystem. The nonlinear response is investigated for different layer composition and different layer thicknesses. The effect of small-scale parameter, as well as base excitation amplitude, is also examined. [ABSTRACT FROM AUTHOR]

As externally powered microsystems become more common, designers need better tools to understand power delivery systems such as non-resonant capacitive coupling. In this paper we present the first general method which allows a designer to easily model power delivery through capacitive coupling. The method uses a power iteration technique which allows one to analyze systems when the time to charge the coupling capacitor is longer than a charge cycle, enabling us to analyze a greater range of systems than previously possible. In fact, we are able to model the entire system with an equivalent resistance. We show that our model accurately reproduces both static and dynamic characteristics of the exact solution and that this model is general, in that it is valid for capacitor charge times that are longer as well as shorter than a charge cycle. This model also reveals several regions of operation where different parameters (e.g., capacitance, frequency and series resistance) dominate, allowing the designer to quickly and intuitively understand the design space for capacitive power transfer. [ABSTRACT FROM PUBLISHER]

A reconfigurable transducer interface circuit that combines the communication and signal conditioning necessary to link a variety of sensors and actuators to a microsystem controller is reported. The adaptive readout circuitry supports high-resolution signal acquisition from capacitive, resistive, voltage and current mode sensors with programmable control of gain and offset to match sensor range and sensitivity. The chip accommodates sensor self test and self calibration and supports several power management schemes. It provides digital and analog outputs to control actuators and a standard interface to peripheral components. The 2.2 × 2.2 mm CMOS chip was fabricated in 0.5-μm, 3-metal, 2-poly process, dissipates ∼ 50 μW at 3.3 V in a typical multisensor application utilizing periodic sleep mode, and can read out a wide range of sensors with high sensitivity. A prototype microsystem with a microcontroller and MEMS pressure, humidity, and temperature sensors has been implemented to characterize interface chip performance. [ABSTRACT FROM AUTHOR]

This paper presents a hand-held microsystem based on new fully integrated magnetoresistive biochips for biomolecular recognition (DNA hybridization, antibody antigen interaction, etc.). Magnetoresistive chip surfaces are chemically treated, enabling the immobilization of probe biomolecules such as DNA or antibodies. Fluid handling is also integrated in the biochip. The proposed microsystem not only integrates the biochip, which is an array of 16 × 16 magnetoresistive sensors, but it also provides all the electronic circuitry for addressing and reading out each transducer. The proposed architecture and circuits were specifically designed for achieving a compact, programmable and portable microsystem. The microsystem also integrates a handheld analyzer connected through a wireless channel. A prototype of the system was already developed and detection of magnetic nanoparticles was obtained. This indicates that the system may be used for magnetic label based bioassays. [ABSTRACT FROM AUTHOR]

In a placebo-controlled study involving 23 patients with craniomandibular disorders, headache, and local pain in the orofacial, cervical, and temporomandibular joint areas, treatment with acupuncture (points chosen using the "very-point" technique) was found to significantly reduce pain, assessed by palpation of 14 muscles and measured according to a visual analogue scale. The authors conclude, "Acupuncture may bring about immediate pain relief in patients with oromyofacial disorders, increasing the chance to initiate other therapeutic measures." [ABSTRACT FROM AUTHOR]