Switched mode power supplies built in LED lamp radiate electromagnetic noise (LED noise) and may interfere with wireless medical telemeters (WMTs). We conducted research on statistical characteristics of LED noise and its effect on the receiver sensitivity of the WMT. We measured timedomain waveform of LED noise. At the wideband reception, LED noise has impulsive characteristics due to high-speed switching, but this impulsive nature is difficult to identify when the narrow bandwidth. Additionally, this noise is to be approximated as Gaussian noise, because the WMTs use a narrow reception bandwidth of 8.5 kHz and LED noise was limited to this bandwidth. We investigated the required signal power of the WMTs for critical reception under interference by LED noise and for comparison with Gaussian noise. The LED noise and Gaussian noise induce similar degradation in the WMT, confirming that the Gaussian approximation is promising for the evaluation of interference in the WMT caused by LED lamps. Moreover, we showed an experimentally investigation of spatial distribution of LED noise around an LED lamp and its power line under the basic configuration. The spatial variation caused by a standing wave of the disturbance current was observed in the parallel direction to the power line, and the noise amplitude was decreased away from the power line in the perpendicular direction.

We worked on validation of sterilization process when we replaced the steam sterilizer in our hospital. During performance qualification process, we used Self-Contained Biological Indicators (BIs) populated with 10⁵, which we usually use.

For minimum-load testing, we set the sterilization time for one min, and we found those BIs were killed completely, then we measured F-value with Data Logger. According to half cycle method, we calculated the sterilization time to accomplish more than 12D, and it turned out to be 4 min and 5 sec.

For maximum-load testing, we used Type 4 Chemical Indicators (CIs, Stated Value:135°C, 6 min and 30 sec), and Helix-PCD test sets to determine the actual sterilization time, considering sterilization effectiveness and steam penetration of instruments in the sterilization containers, which we assume to be the most difficult to be sterilized.

Then, we finally set the sterilization time for 6 min, which is enough for Type 4CIs to react, to avoid human errors during routine monitoring.

We tested whether surface contamination occurs after packaging probiotic powder (Biofermin; contains 1.1x10⁹ colony forming units (cfu) Enterococcus faecalis) after one use of a fully-automated powder packaging machine. The machine was washed normally once, as recommended followed by three rounds of rinsing in lactose as a means for additional wash. We quantified the viable bacteria in the lactose rinse in the three separate attempts, finding 1.4x10⁵ cfu/g in the first, 6.5x10⁴ cfu/g in the second, and 2.0x10⁴ cfu/g E. faecalis in the third rinse. We found that three additional wash still leaves 0.019%, 0.009% and 0.003% of the bacteria in the automated machine respectively to each trial. The results suggest that contamination of the automated machine persists even after three additional wash with lactose. It further suggests that preparing cancer therapy drugs , for example, by automated powder packaging machine may carry some contamination risks.