Fouling effect testing

The effect of electrode fouling was tested by obtaining calibration curves at two UMBs, one with enzyme and poly( 1,3-DAB), and one with enzyme only. Both UMBs were then placed in a 3% w/v BSA solution in pH=7.4 buffer, for 6 h, at T=4°C. After 6 h, the UMBs were removed, rinsed, and calibration curves were again obtained. The sensitivity of the UMB with polymer film decreased by 10%, some of which can be attributed to experimental error. The sensitivity of the UMB without polymer film decreased over 30%. 

The effect of the polypyirole film on the oxidation of 2 model interferences, acetaminophen and ascorbate was dramatic with the currents being reduced to <1% of their previous values. Furthermore the protective effect was reasonably durable since measurements of c. 250 injections, made over a period of some 17 hours showed only a c. 4 fold increase in the currents due to these compounds. Tests have also been made in diluted complex yeast extract medium (1 100 dilution). An unmodified electrode displayed considerable fouling when tested with this solution, the current falling to c. 30% of the initial value within 6 hours, accompanied by a large increase in the... 

The average effective diffusivity calculated for the 44 compositions is 1.7 x 10"13 cm2/sec and the loss of tin 2.2%. These are in qualitative agreement with the results of laboratory testing. Cardarelli has also reported that antifouling rubber retains a considerable amount of organotin additives even after complete fouling (11). 

In 2005 and 2007 (Phase 2), a more recent study for the U. S. Marine Corps, by Hill et al., evaluated 13 self-applied tourniquets for their applicability in combat applications. This study attempted to measure the functionality of the candidate tourniquets in battlefield conditions by immersing them in a simulated blood/sand mixture prior to testing. In contrast to the earlier Army study by Walters et al., the conclusion drawn from this study was the recommendation that one of the ratcheting or stretch-retention type tourniquet systems be adopted for combat deployment. These types had the best user subjective ratings as well as the lowest application times especially on the upper extremities where one-handed application was required. The recommended group had application times 30-50% lower on the upper extremities than the windlass types recommended by the Army study. Velcro was observed to lose its effectiveness as a clamp when it became fouled with wet sand or mud and, therefore, should be avoided. It should be noted that none of the tourniquet types used in the Marine Corps study were pneumatic. 

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