In this study, low pressure non-thermal radiofrequency nitrogen plasma at very low power has been used to treat the artichoke seeds on the powered cathode for the first time. The influence of treatment time on the surface physical properties, germination rate, seedling growth, and enzyme activity of the seeds has been investigated. Results showed that plasma treatment considerably improved the germination rate and seedling growth. The root length grew by 28.5% and 50% and root dry weight increased by 13% and 53%, respectively, for 10 and 15 min of treatment. The same trend has been found for the shoot growth parameters although the greater stimulatory efficacy on root has been obtained. The nitrogen plasma treatment substantially made the seeds' surface hydrophilic which leads to 36.9% improvement in seed's water uptake at 15 min of treatment. Our study showed the activity of peroxidase and catalase enzymes slightly increased after the plasma treatment.

In this study, two models of flat film and three-dimensional porous structure made by 3D printing (scaffolding) of poly lactic acid polymer (PLA) were processed by radio frequency (RF; 13.56 MHz) low-pressure nitrogen, nitrogen/oxygen and nitrogen/hydrogen plasma to improve surface properties requested in tissue engineering. Samples were treated at different RF power (80–150 w) and time processing was 90 s. Optical emission spectroscopy was used to identify the species in plasma. A significant change in hydrophilicity and surface energy measured by contact angle was observed. Aging effect on the wettability of PLA films at two different temperatures was examined. The result showed that the samples, kept at low temperature, have not changed significantly. Morphology and surface roughness were studied by Atomic force microscopy. Chemical components at the surface were investigated by x-ray photoelectron spectroscopy (XPS). Mechanical and thermal effect on the 3D scaffold PLA were carried out by tension test and thermogravimetric analysis respectively to indicate the effects of RF plasma treatment on the samples. The structural order, interconnectivity, and scale of the scaffold holes have been recorded by an optical microscope. Surface treatment by plasma increased biocompatibility of PLA samples without any toxicity. Cell adhesion on scaffolds was approved through MTT and scanning electron microscope (SEM) analysis. MTT essay show there was significant different between N2/O2 (1:1) group than control sample. Plasma surface treatment is a convenient method to reach a perfect substrate with desired hydrophilicity for attaching cells.

Dielectric barrier discharges (DBD) are often used for gas conversion such as splitting of carbon dioxide, volatile organic compound removal or ozone generation. Due to the small plasma filaments in DBD discharges an efficient mixing of the gas flow with the plasma is essential. This is studied by using a surface dielectric barrier discharge (sDBD) with an electrode design similar to plasma actuators to optimize plasma-flow interaction. The flow pattern has been measured by Schlieren diagnostics and compared to a fluid dynamic simulation. The efficiency of gas conversion has been tested by monitoring the conversion of 1\% CO$_2$ admixed to an N$_2$ gas stream via infrared spectroscopy in the exhaust. The actuator design of the electrodes induces a significant plasma force on the fluid, which results in the formation of vortices above the electrodes as reproduced in the simulation. It is shown that the height of the vortices created in the velocity field can characterize the mixing process, which dominates the conversion efficiency of carbon dioxide at different gas flow rates.