T. J. Anderson

The application of dielectrophoretic field-flow fractionation (depFFF) to the isolation of circulating tumor cells (CTCs) from clinical blood specimens was studied using simulated cell mixtures of three different cultured tumor cell types with peripheral blood. The depFFF method can not only exploit intrinsic tumor cell properties so that labeling is unnecessary but can also deliver unmodified, viable tumor cells for culture and/or all types of molecular analysis. We investigated tumor cell recovery efficiency as a function of cell loading for a 25 mm wide x 300 mm long depFFF chamber. More than 90% of tumor cells were recovered for small samples but a larger chamber will be required if similarly high recovery efficiencies are to be realized for 10 mL blood specimens used CTC analysis in clinics. We show that the factor limiting isolation efficiency is cell-cell dielectric interactions and that isolation protocols should be completed within approximately 15 min in order to avoid changes in cell dielectric properties associated with ion leakage.

Droplet-based programmable processors promise to offer solutions to a wide range of applications in which chemical and biological analysis and/or small-scale synthesis are required, suggesting they will become the microfluidic equivalents of microprocessors by offering off-the-shelf solutions for almost any fluid based analysis or small scale synthesis problem. A general purpose droplet processor should be able to manipulate droplets of different compositions (including those that are electrically conductive or insulating and those of polar or non-polar nature), to control reagent titrations accurately, and to remain free of contamination and carry over on its reaction surfaces. In this article we discuss the application of dielectrophoresis to droplet based processors and demonstrate that it can provide the means for accurately titrating, moving and mixing polar or non-polar droplets whether they are electrically conductive or not. DEP does not require contact with control surfaces and several strategies for minimizing surface contact are presented. As an example of a DEP actuated general purpose droplet processor, we show an embodiment based on a scaleable CMOS architecture that uses DEP manipulation on a 32 x 32 electrode array having built-in control and switching circuitry. Lastly, we demonstrate the concept of a general-purpose programming environment that facilitates droplet software development for any type of droplet processor.

PURPOSE: The main purpose of this prospective study was to analyze whether 1 year of treatment was as effective as 3 years with respect to remission rate in children with idiopathic epilepsy. METHODS: Treatment for epileptic seizures was started in 207 children aged 2-16 years. They were randomized to treatment for 1 or 3 years. At the end of the predetermined treatment period, 161 children had been seizure-free for 6 months and the treatment could be gradually withdrawn. RESULTS: The overall remission rate in our group of patients was significantly higher (71%) in the group treated for 3 years than in the group treated for 1 year (53%). However, comparison of remission rates between patients with different seizure types showed statistically significant differences in outcome depending on duration of treatment only in children with complex partial seizures (CPS). CONCLUSIONS: Our results show that 1 year of treatment can be recommended in children with benign partial epilepsy with rolandic spikes (BECT) and in children with simple partial seizures (SPS) but is clearly insufficient in children with CPS. A proper seizure classification is one important tool, although not sufficient, in offering recommendations concerning the duration of treatment in children with idiopathic epilepsy.

A difficulty in reliability modeling is how to capture the impact of all of the various reliability defect types. The general approach to optimizing burn-in that we describe in this article addresses a multiple-defect environment. The approach has four main parts: (i) modeling the product's failure rate distribution, (ii) establishing the Pareto distribution of reliability defects, (iii) assessing the kinetic information of each reliability defect, and (iv) estimating the DPPM under product use conditions. This article compares and contrasts the acceleration effects of various extrinsic defects found in 130- and 90-nm CMOS technology products.

The ability to meet ever more demanding customer quality and reliability requirements is becoming increasingly difficult with each advancing technology generation. This issue becomes more complex as customer applications and requirements become more varied for the same basic technology. The customer applications range from cell phones and PDAs to servers to automotive. The reliability requirement descriptions vary from hundreds of defective parts per million (DPPM) to five nines availability to a zero defects culture. This paper focus on how customer quality and reliability expectations are influencing the perception and direction of test