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This paper reports the design, fabrication procedure and functional tests of a continuous-flow hybrid technology 16-line evaporative concentrator. The unique and complete integration of the microscale silicon-glass evaporator with a mesoscale 3D printed polymer manifold platform is successfully demonstrated. The hardware platform of concentrator control unit is described. The continuous-flow concentrator chips were tested with respect to their evaporation capability. A very high water evaporation rates were achieved in evaporative concentrator. An evaporation rate of 10 μL/min, achieved in mild conditions, compatible with biological sample treatment (T≤37°C), allowed for 4-fold sample enrichment. High-throughput flow ability and 33-fold concentration factor achieved in temperature of 50°C facilitates the application of prototype for chemical sample enrichment.

In this paper we describe components for integrated microliquid handling systems such as fluid injection analysis, and first results of planar integration of components. The components discussed are channels, passive and active valves, actuators for micropumps, micromixers, microflow sensors, optical detectors, pumps and dosage systems. The dosage system described comprises a flow sensor and a pump micromachined on a single silicon wafer sandwiched between Pyrex wafers. The liquid pump is of the reciprocating type with a thermo-pneumatic actuator. The microliquid flow sensor is based on the thermal anemometer type. Both pump and flow sensor are realized in a 3 inch (100)- Si wafer using a KOH bulk etch from both sides of the wafer. The dosing system allows accurate dosing of liquid in the mu l regime and can easily be integrated with components as mixers and detectors to microliquid handling systems. A new concept for micromixing of liquids is introduced and its feasibility is demonstrated. The mixer allows fast mixing of small amounts of two liquids and it is applicable to microliquid handling systems. The mixer has a channel for the liquid, an inlet port for the reagent, and a mixing area, the bottom of which has 400 micronozzles (15 mu m*15 mu m). Through these nozzles, a reagent is injected into the sample liquid, making many microplumes. These plumes speed up mixing by diffusion over a short distance.

We investigated 185 adolescents under the age of 19 years with spondylolysis. All but five were active in sport. The pars defect was classified into early, progressive and terminal stages. Of the 346 pars defects in 185 patients, 39.6% were early, 29.5% progressive and 30.9% in the terminal stages. Conservative management produced healing in 73.0% of the early, 38.5% of the progressive and none of the terminal defects. These results suggest that spondylolysis is caused by repetitive microtrauma during growth and can be successfully treated conservatively if treatment is started in the early stage. There was elongation of the pars interarticularis as the pars defect progressed, and this is likely to be a consequence of the defect rather than a contributing cause.

A new concept for micro-mixing of liquid is introduced and feasibility is demonstrated. The mixer allows fast mixing of small amounts of two liquids and it is application to micro-liquid handling systems [1]. The mixer has a channel for the liquid, an inlet port for the reagent, and a 2.2 mm × 2 mm × 330 μm mixing area, and its bottom has 400 micro-nozzles (15 μm × 15 μm). Through these nozzles, a reagent is injected into the sample liquid, making many micro-plumes. These plumes increase the contact surface between the two liquids drastically, and hasten the speed of the mixing by diffusion. The nozzle holes and channel are etched using KOH into a 3-inch (100)-Si wafer from both sides. The fabrication process is extremely simple. Flow visualization by microscope shows the mixing is complete within a few seconds, and absorptiometry using a pair of optical fibers showed that a homogeneous state of mixing is reached in 1.2 seconds, when the total volume injected is 0.5 μl and the injection flow rate is 0.75 μVs.