Observation of Effectiveness of Clinical Sterilization by CASP-80A Low-Temperature Plasma Sterilizer

The influence on the effectiveness of sterilization by low-temperature plasma sterilizer CASP-80A was investigated so as to provide a theoretical basis for reducing medical costs and achieving ideal sterilization effectiveness. To conduct the on-site simulation test, a clinical material sterilization test and a test of the influence of organic substance were conducted, the former by using the representative of Bacillus Stearothermophilus, preparing the bacteria-contaminated carrier through polytetrafluoroethylene （PTFE） simulated hose endoscopes, and the latter by using calf serum as the influence factor of the organic substance. The results show that the CASP-80A low-temperature plasma sterilizer could achieve effective sterilization by either the short-cycle or the long-cycle sterilization method depending on different materials, apparatus, and extent of contamination. The organic substances could influence the effectiveness of sterilization by the low-temperature plasma （H2O2） sterilizer.

Realizing high efficiency and large-area sterilization by a rotating plasma jet device

By tilting a plasma jet and rotating 360°,a large-area can be scanned and sterilized in a short time.Compared with the previous array device,this pipe has the significant advantages of high sterilization uniformity and low gas consumption.Firstly,a rotatable plasma jet device,which can control the swing and rotation of a jet pipe,is designed,and a corresponding theoretical model is established to guide the experiment.Secondly,with Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)as the target bacteria,the device achieves a short sterilization time of 158 s—the minimum sterilization flow of S.aureus and E.coli is 0.8 slm and 0.6 slm,respectively.The device is compared with an array plasma sterilization device in terms of sterilization speed and gas consumption.The results show that the device is not only better than an array plasma sterilization device with respect to scanning uniformity,but also far less than the array plasma sterilization device in gas consumption of 5 slm.Therefore,the device has great potential in applications involving efficient,large-area sterilization.

Sterilization of Turmeric by Atmospheric Pressure Dielectric Barrier Discharge Plasma

In this study atmospheric pressure dielectric barrier discharge （DBD） plasma has been employed for sterilizing dry turmeric powders. A 6 kV, 6 kHz frequency generator was used to generate plasma with Ar, Ar/Ou, He, and He/O2 gases between the 5 mm gap of two quartz covered electrodes. The complete sterilization time of samples due to plasma treatment was measured. The most important contaminant of turmeric is bacillus subtilis. The results show that the shortest sterilization time of 15 rain is achieved by exposing the samples to Ar/O2 plasma. Survival curves of samples are exponential functions of time and the addition of oxygen to plasma leads to a significant increase of the absolute value of time constant of the curves. Magnitudes of protein and DNA in treated samples were increased to a similar value for all samples. Taste, color, and solubility of samples were not changed after the plasma treatment.

The Effect of Atmospheric Pressure Plasma Corona Discharge on pH, Lipid Content and DNA of Bacterial Cells

Effect of plasma corona discharges on the pH, whole cell lipids and DNA of bacteria is investigated. Results showed an increase in the acidity levels of water due to plasma reactive species which, however, were not responsible for bacterial cell death. No changes in the whole cell lipid contents were observed, while DNA after plasma treatment showed deterioration of the amplified sequences, indicating the possible occurrence of DNA degradation. In conclusion, reactive species produced by plasma discharges affects DNA, possibly contributing to cell death.

Inactivation of Escherichia Coli Using Remote Low Temperature Glow Discharge Plasma

Low-temperature plasma is distinguished as a developing approach for sterilization which can deal with and overcome those problems such as thermal sensitivity and destruction by heat, formation of toxic by-products, higher costs and inefficiency in performances, caused by conventional methods. In this study, an experimental investigation was undertaken to characterize the effects of the operational parameters, such as treating time, discharge power and gas flow rate, of remote glow discharge air plasma. The results show that the inactivation of Escherichia coli can reach above 99.99% in less than 60 seconds and the optimal operational conditions for treating time, discharge power and gas flow rate were： 40 s, 80 W and 60 cm^3/min, respectively. The contribution of UV radiation during plasma germ deactivation is very limited.