Cold atmospheric plasma (CAP) is a 'partially ionized' gas composed of free electrons, positive and negative ions, radicals, excited species, an electric field, and ultraviolet radiation (UVR) [1][2][3][4]. One of the most important advantages of cold plasma is its ability to work at room temperature and atmospheric pressure, which makes it possible to be utilized in biological media with minimal thermal side effects [5][6][7][8]. In this regard, the prominent applications of CAP are microorganism

Nonlinear heating of collisional plasma when the temporal extent of the laser pulse is smaller than the ambipolar diffusion time has been investigated. The nonlinearity in a collisionless plasma arises through the ponderomotive force, whereas in collisional plasmas ohmic nonlinearity prevails. In this case, by considering the nonrelativistic ponderomotive force effect and the variation of the collision frequency between electrons and ions due to the temperature change, the nonlinear dielectric permittivity of the plasma medium is obtained and the equation of the electromagnetic wave propagation in underdense plasma is solved. It is shown that in this case, due to the ohmic heating of electrons, the effect of the ponderomotive force in the nonrelativistic regime leads to steepening of the electron density profile and decreases the temperature of the plasma electrons noticeably. Bunches of electrons in plasma become narrower and by increasing the laser pulse strength the wavelength of density oscillations decreases. In this regime of laser–plasma interaction, the electron temperature decreases sharply with increasing the intensity of laser pulses.

Cold atmospheric plasma has established its effect on cell adhesion. Given the importance of cell adhesion in stem cells, the current study investigates the effect of plasma treatment on Human Bone Marrow Mesenchymal Stem Cells (HBMMSCs) adhesion by which the differentiation and fate of cells are determined. In this paper, adhesion modification is considered not only for cell- ECM (Extra cellular Matrix), but also between suspended cells, and enhanced adhesions were found in both circumstances. Regarding the previous works, the increase of the cell–ECM adhesion during the plasma therapy was mostly attributed to the enhancement of the production and activity of integrin proteins. Nevertheless, considering the importance of van der Waals forces at the cellular level, the effect of cold plasma on VDWFs and so its effect on adhesion is investigated in this work for the first time, to the best of our knowledge. For this purpose, employing the semi-empirical methods, the role of the plasma therapy on the VDWF between the cells has been studied at three levels; (a) plasma-induced dipole formation, (b) Hammaker coefficient modification of culture medium, and c) cell roughness modification. For suspended cell condition, we conclude and support that van der Waals forces (VDWFs) enhancement has a key role in cell adhesion processes. We believe that, the present work gives a new physical insight in studying the plasma therapy method at the cellular level.

Regarding the fact that cell shape indicates cell health and is of particular importance in the evaluation of new therapies, in this study, stem cell deformation during Atmospheric Pressure Plasma (APP) treatment was investigated. Given that, cell deformation is a warning of cell damage, it is therefore expected that APP-based therapy, a new modern technology that is expanding worldwide, will not lead to the deformation of normal cells. Here, the stem cells exposed to Helium-fed jet plasma, with two di erent powers of 15 and 25W. Moreover, the duration of exposure was changed (30, 50, 70, and 90 seconds) to determine the most appropriate exposure time and voltage, which maintains stem cells’ health condition. First of all, it was found that cold plasma at low power does not change the shape and elongation of stem cells. Besides, it was found that if the power of a cold plasma source is 25W, it will raise cell growth rate. In this paper, the gas ow rate of the helium plasma jet was set to 3.9 liters per minute, and a plasma source frequency of 30kHz was selected.

Using dielectric barrier discharge reactor (DBD) to convert CO2 has attracted considerable attention, recently. The primary challenge with its industrial use, however, is the eligibility and effectiveness of this technology in CO2 conversion, as well as its cost of energy. In this research use has been made of Artificial Neural Network to investigate the effective factors on a DBD reactor, a unique modern instrument for CO2 conversion. A multilayer perceptron approach of feed-forward back-propagation (BP) has been utilized to increase both the energy and CO2 conversion efficiency (outputs) by modeling the effective factors, such as chamber size, gas flow rate, and plasma-generator power (inputs). The findings revealed that an artificial neural network can be used to explain the eligibility and efficiency. Despite the network’s complexity in terms of input and output parameters, the predicted and actual results were found to be in good agreement. The results showed that multilayer perceptron with structure 3-6-2 was the most suitable (MSE = 0.62 and R2 > 0.99). As a result, the artificial neural network can be utilized as a practical and effective tool in predicting the efficiency of energy and carbon dioxide conversion in a DBD reactor.

Cold atmospheric plasma has established its effect on cell adhesion. Given the importance of cell adhesion in stem cells, the current study looked at the effect of plasma treatment on stem cell adhesion by which the differentiation and fate of cells are determined. In this paper, adhesion modification was investigated not just among cell-ECM, but also between suspended cells, and enhanced adhesions were found in both circumstances. Regarding the previous works, increasing the cell-ECM adhesion during the plasma therapy could be mostly attributed to enhancing the production and activity of integrin proteins, while at the suspension condition, we have showed that this increasing is due to the enhancing in van der Waals forces (VDWFs) between the cells. Considering the importance of van der Waals forces at the cellular level, the effect of cold plasma on VDWFs and so its effect on adhesion were investigated in this work for the first time, to the best of our knowledge. For this purpose, employing the semi-empirical methods, the role of the plasma therapy on the VDWF between the cells has been studied at three levels; a) plasma-induced dipole formation, b) Hammaker coefficient modification of culture medium, and c) cell roughness modification. We believe that, the present work gives a new physical insight in studying the plasma therapy method at the cellular level.

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