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Gas breakdown in large scale systems has been widely studied and is reasonably well understood. Deviations from the well-known Paschen law, however, have been reported in microgaps. One possible mechanism responsible for these deviations is the increase of the secondary electron emission yield due to the quantum tunnelling of electrons from the metal electrodes to the gas phase. The high electric fields obtained in small gaps combined with the lowering of the potential barrier seen by the electrons in the cathode as an ion approaches lead to the onset of ion-enhanced field emissions. Particle-in-cell/Monte Carlo simulations including ion-enhanced field emission have been performed to evaluate the importance of these mechanisms in the discharge breakdown. Deviations from the Paschen curve in gaps smaller than 5 µm can be explained based on this mechanism. [ABSTRACT FROM AUTHOR]

Single fluid linear simulations of a KSTAR RMP ELM suppressed discharge with the M3D-C1 resistive magnetohydrodynamic code have been performed for the first time. The simulations show that the application of the n  =  1 perturbation using the KSTAR in-vessel control coils (IVCC), which apply modest levels of n  =  3 sidebands (~20% of the n  =  1), leads to levels of n  =  3 sideband that are comparable to the n  =  1 when plasma response is included. This is due to the reduced level of screening of the rational-surface-resonant n  =  3 component relative to the rational-surface-resonant n  =  1 component. The n  =  3 sidebands could play a similar role in ELM suppression on KSTAR as the toroidal sidebands (n  =  1, 2, 4) in DIII-D n  =  3 ELM suppression with missing I-coil segments (Paz Soldan et al 2014 Nucl. Fusion54 073013). This result may help to explain the uniqueness of ELM suppression with n  =  1 perturbations in KSTAR since the effective perturbation is a mixed n  =  1/n  =  3 perturbation similar to n  =  3 ELM suppression in DIII-D. [ABSTRACT FROM AUTHOR]

As interest has increased in the interaction between low-temperature plasmas and living cells or organic materials, the role of modelling and simulation of atmospheric pressure plasmas has become important in understanding the effects of charged particles and radicals in biomedical applications. This review paper introduces the general properties of low-temperature atmospheric pressure plasma devices for biomedical applications and explains recently reported simulation results. Control parameters of atmospheric pressure plasmas, such as gas mixture composition, driving frequency and voltage and the function shape of sinusoidal and pulsed power, are considered through both a review of previous findings and new simulation results in order to improve plasma properties for given purposes. Furthermore, the simulation or modelling techniques are explained along with surface interactions of the plasma for the future development of simulation codes to study the interaction of plasmas with living cells. [ABSTRACT FROM AUTHOR]

Low-energy electrons are confined in the bulk plasma by the ambipolar potential and are typically heated inefficiently due to their low collisionality and the weak rf electric field present in the bulk when their mean-free path is much larger than the system length in capacitively coupled discharges. It is shown in this study, however, that electrons in the bulk that bounce inside the electrostatic potential well with a frequency equal to the rf excitation frequency are efficiently heated by coherent interaction with the rf field. This resonant heating manifests itself as a plateau in the electron energy probability function and is observed in a wide range of pressures from 25 mTorr to 1 Torr while decreasing the gap distance. The weak transverse magnetic field significantly influences the bounce frequency of the low-energy electrons. As a result, the electrons not in the resonant condition in the absence of a magnetic field can be led to satisfy the resonant condition, becoming effectively heated in the presence of a weak transverse magnetic field. [ABSTRACT FROM AUTHOR]

Bone marrow-derived mesenchymal stem cells (MSCs) have the potential to differentiate into a variety of cell types, including osteocytes, chondrocytes, and adipocytes. Moreover, MSCs have the capacity to differentiate into neural lineages. The present study aimed to investigate the differences between the expression profiles during neural differentiation of rat and cat MSCs. MSCs in the 4th passage, which were isolated from the femurs and tibias by standard methodology, were used in our study. Culture media was divided into pre-induction medium, which consisted of DMEM-HG, 10% fetal bovine serum, 10 ng mL-1 of basic fibroblast growth factor (bFGF), and 1 mM -mercaptoethanol, for 24 h, and neuron induction medium, which was composed of DMEM-HG, 2% DMSO, 200 M BHA, 25 mMKCl, 10 M forskolin, 5 g mL-1 insulin-transferrin-sodium selenite, and 20 ng mL-1 bFGF, for 24 h. Thereafter, cell morphology and growth traits were determined by light microscopy imaging and by examining the cell-surface antigen profile and differentiation repertoire by immunocytochemistry, respectively. Regarding the expression of 3 MSC-related surface antigens, rat cells were positive for CD18 and CD44, whereas cat cells expressed CD9 and CD44. Under proneurogenic conditions, rat neuron-like cells progressively increased at 30 min post-induction, peaked at 1 h, and gradually declined after 12 h. At 24 h after neural induction, there were still some neuron-like cells. Meanwhile, cat cells were expressed increasingly during the first hour, peaked at 2 to 3 h, were sustained for 8 h after neural induction, and then gradually declined.A few neuron-like cells remained until 24 h post-induction. In neural differentiation, rat MSCs were positive for III-tubulin, NF-L, NF-M, NF-H, trkA, and vimentin; cat MSCs were negative for III-tubulin and NF-H but positive for NF-L, NF-M, trkA, and vimentin. Both MSCs were negative for oligodendrocyte markers. Our results revealed that there is variation in neural differentiation sensitivity due to species type. Rat cells were more sensitive in response to neuroinduction agents, maintained their morphology for a longer time, and expressed relatively mature neuronal markers. On the contrary, the sensitivity of cat cells was weaker, and survival time was shorter compared to that of the rat cells. The cat cells expressed immature neuronal markers. The present data suggest a significant aspect of the culture of MSCs from higher-grade species.This work was supported by KOSEF (Grant ? M10525010001-05N2501-00110). [ABSTRACT FROM AUTHOR]