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The trace‐O2 removal in coke oven gas, which enables better utilization of its contained H2, is investigated with combinations of atmospheric nonthermal plasma and a Pt/γ‐Al2O3 catalyst. Herein it is shown that a coaxial packed‐bed dielectric barrier discharge (DBD) reactor removes up to 80 % O2 in a model coke oven gas. Along this line, the H2 content and the usage of Al2O3 granules in the plasma zone have been identified as major factors for the plasmachemical trace‐O2 conversion. In contrast to the Pt/γ‐Al2O3 catalyst, nonthermal plasma converts trace O2 at coke oven gas temperatures below 100 °C. [ABSTRACT FROM AUTHOR]

Most studies regarding plasma biomedicine applications mainly focus on the oxidative and/or nitrative stress on bacteria, cancer cells, and other treatment objects. In this study, we evaluate the protective effect of appropriate atmospheric pressure plasma jet (APPJ) treatments on oxygen and glucose deprivation (OGD)‐induced neural cell apoptosis, which is a major pathological process during ischemic stroke, based on the physiological functions of NO. Results show that APPJ treatment reduces the OGD‐induced apoptosis by weakening typical OGD injury consequences including loss of mitochondrial membrane potential, the release of cytochrome c from the mitochondria into the cytoplasm, lower antiapoptotic Bcl‐2 expression, and upregulating the proapoptotic protein Bax. Furthermore, APPJ increased intracellular NO production, which is closely related to the cytoprotective effect of APPJ. [ABSTRACT FROM AUTHOR]

Plasma‐activated water mist (PAWM) is obtained by the ignition of plasma within an air–vapor mixture. PAWM demonstrates significant antibacterial properties, decreasing loads of foodborne pathogens by a factor of 35.5 for Listeria monocytogenes, 166 for Salmonella Typhimurium, and 266 for Escherichia coli O157:H7 within 15 s. Bacterial biofilms have a similar species‐dependant susceptibility. Biofilms of L. monocytogenes, Salmonella Typhimurium, and E. coli O157:H7 are destroyed by 44%, 77%, and 71%, respectively, after being treated for 2 min. Obtained results suggest importance of short‐lived radicals, because PAWM condensate is not bactericidal. A new model of PAW generation as a cyclic process of oxidation reactive nitrogen species by reactive oxygen species, which occurs during effective bidirectional mass transfer between heavily humid air and water mist in plasma discharge, is presented. [ABSTRACT FROM AUTHOR]

Vaccination has been one of the most effective health intervention mechanisms to reduce morbidity and mortality associated with infectious diseases. Vaccines stimulate the body's protective immune responses through controlled exposure to modified versions of pathogens that establish immunological memory. However, only a few diseases have effective vaccines. The biological effects of nonthermal plasma on cells suggest that plasma could play an important role in improving efficacy of existing vaccines and overcoming some of the limitations and challenges with current vaccination strategies. This review summarizes the opportunities for nonthermal plasma for immunization and therapeutic purposes. [ABSTRACT FROM AUTHOR]

The penetration of reactive oxygen and nitrogen species (RONS) across the stratum corneum (SC) is a necessary and crucial process in many skin‐related plasma medical applications. To gain more insights into this penetration behavior, we combined experimental measurements of the permeability of dry and moist SC layers with computer simulations of model lipid membranes. We measured the permeation of relatively stable molecules, which are typically generated by plasma, namely H2O2, NO3−, and NO2−. Furthermore, we calculated the permeation free energy profiles of the major plasma‐generated RONS and their derivatives (i.e., H2O2, OH, HO2, O2, O3, NO, NO2, N2O4, HNO2, HNO3, NO2−, and NO3−) across native and oxidized SC lipid bilayers, to understand the mechanisms of RONS permeation across the SC. Our results indicate that hydrophobic RONS (i.e., NO, NO2, O2, O3, and N2O4) can translocate more easily across the SC lipid bilayer than hydrophilic RONS (i.e., H2O2, OH, HO2, HNO2, and HNO3) and ions (i.e., NO2− and NO3−) that experience much higher permeation barriers. The permeability of RONS through the SC skin lipids is enhanced when the skin is moist and the lipids are oxidized. These findings may help to understand the underlying mechanisms of plasma interaction with a biomaterial and to optimize the environmental parameters in practice in plasma medical applications. [ABSTRACT FROM AUTHOR]

The soliton waves are one of the nonlinear phenomena which can propagate in the different types of plasma such as multiple particles of plasma, nonthermal plasma, and space plasma. Using the Sagdeev potential technique, the stability conditions of the soliton waves in the nonthermal plasma have been theoretically studied. One of the significant factors that can affect the propagation of the soliton waves is the distribution function such as nonMaxwellian distribution function or Kappa distribution function. In this paper, we try to investigate the soliton wave in the unmagnetized multi-component plasma consisting of the nonthermal electron and the nonthermal ion, positron and dust with Kappa distribution function. Then by using the Sagdeev potential, the nonlinear equation for the potential is obtained and then the compression and rarefaction soliton waves are computed with the numerical method for this nonlinear wave. Finally, by imposing the Sagdeev potential condition, we discuss the stability of these soliton waves. [ABSTRACT FROM AUTHOR]

To disclose water roles in plasma reforming of methanol for hydrogen production, gliding arc discharge characteristics, optical emission spectra, and reaction behavior are investigated over a water concentration range of 0–95 mol%. It can be concluded that the varied reaction behavior with water concentration derives from three water roles as a homogeneous catalyst, CO oxidant, and side‐product. The former two roles of water are beneficial for hydrogen production. The side‐product role of water, accompanied by hydrocarbons formation, which is disadvantageous to hydrogen production and can be almost fully inhibited by the homogeneous catalysis of water at above 33 mol% H2O. As an oxidant, water conversion is controlled by the thermodynamic equilibrium at the gas temperature of arc. [ABSTRACT FROM AUTHOR]

Solid structures of different shapes, hydrogen chloride, and a small number of liquid products are formed from chloromethanes (CH2Cl2 and CHCl3) and binary systems with triphenylphosphine (CH2Cl2 + PPh3, CHCl3 + PPh3, and CCl4 + PPh3) under the action of a liquid‐phase low‐voltage discharge (60‐V DC). It is observed that triphenylphosphine additives sharply increase the reactivity of CCl4. Besides, a quantum chemical simulation of chloromethane transformation mechanism in the binary systems with triphenylphosphine is conducted, together with the likely mechanism of chloromethane conversion into active particles under the action of a liquid‐phase low‐voltage pulsed discharge. [ABSTRACT FROM AUTHOR]

Si nanocrystals (NCs) are synthesizable in low-pressure plasmas with narrow diameter distributions because of unipolar negative charging in the plasma. However, NCs must pass into a spatial afterglow, where NCs may decharge and aggregate. We use both low-pressure differential mobility analysis and quantitative TEM image analysis to examine Si NCs sampled from a 2 Torr Ar-SiH 4 plasma reactor. We find that Si NCs are incorporated into aggregates largely composed of 20 and fewer primary particles with nearly equal concentrations of negatively and positively charged NCs. The projected areas of aggregates scale with aggregate volume in similar manner to the scaling observed for aggregates from atmospheric pressure systems. Higher aggregate concentration is observed with increasing flow rate, while larger aggregate size is found with increasing precursor concentration. Measurements show that the spatial afterglow has a significant influence on the charge and extent of NC aggregation. Unlabelled Image • The size structures of Si Nanocrstyals (NCs) are characterized from a plasma. • Characterization combines differential mobility analysis and TEM image analysis. • Influence of spatial afterglow on NC charge levels and aggregation is quantified. • Aggregate structure is similar aggregates from atmospheric pressure systems. [ABSTRACT FROM AUTHOR]

This article presents a numerical model and simulation results for the flow stabilization problem behind a solid cylinder. Four dielectric barrier discharge actuators are attached to the cylinder surface, each consisting of two tape electrodes. The surface-exposed electrodes are supplied with a high sinusoidal voltage, whereas the embedded ones are electrically grounded. A surface low-temperature plasma is generated near the edge of the exposed electrode, where the electric field intensity is very high. Ions generated by the discharge drift along the cylinder surface and collide with neutral air molecules, generating airflow. This electrohydrodynamic flow suppresses, or completely eliminates, the flow separation in the downwind part of the cylindrical surface. It can also quench, or mitigate, the von Kármán vortices behind the cylinder. The simulation results reasonably agree with the experimental data published in the literature, validating the proposed numerical algorithm. [ABSTRACT FROM AUTHOR]

Integrating oxide coatings with narrow‐gap hybrid discharge (HD) can modulate ozone (O3) synthesis. O3 concentration (CO3) and energy yield (η) for HD can be enhanced by single‐valent oxides, whereas they are reduced by multivalent oxides. The discharge and oxide characterizations suggest that surface catalytic reactions play a crucial role in the synthesis of O3: single‐valent oxide coatings facilitate O3 production by offering abundant catalytic sites for surface catalytic reactions; surface catalytic reactions on multivalent oxide coatings suppress O3 production because of the dominating O3 decomposition over highly active sites of oxygen vacancies. This study is inspirational for designing and fabricating high‐efficiency O3 generators. [ABSTRACT FROM AUTHOR]

A pulsed bipolar plasma-catalytic system was used to treat organic waste gases over perovskite catalysts. The characteristics of the catalyst impedances, plasma discharge, and in situ optical emission spectra were represented for describing the plasma and catalyst actions. Compared with the reaction without plasma, the temperature at 99% conversion of butanone oxidation over La0.7Sr0.3MnO3/mullite catalyst at SED of 3.340 kJ L−1 reduced from 320 to 198 °C for the reaction with plasma. The maximum residual amounts of toluene and butanone in ozone after plasma catalysis were 0.30 and 0.52 ppmv, respectively. No organic by-products were observed in the plasma-catalysis. A synergy factor in the terms of the temperature was defined for the synergistic catalysis. Plasma-dissociation and synergistic catalysis were integrated into the plasma-catalytic reaction to establish the theoretical formula of the reaction by introducing the synergy factor. The results demonstrate that this formula can successfully interpret the behaviors of plasma-catalysis. [ABSTRACT FROM AUTHOR]

We discuss the synthesis and properties of nanoparticles and thin films for refractory plasmonic applications. The approach focuses on titanium nitride (TiN), which overcomes the limitations of more common plasmonic materials like silver and gold with respect to temperature stability. Freestanding TiN-based nanoparticles are produced in two serially connected plasma reactors, where TiN nanocrystals are nucleated in a first plasma stage, then aerodynamically dragged in a second stage, and conformally coated with a silicon nitride layer. An in-depth comparison between bare and coated TiN nanoparticles is presented in terms of the structural, chemical, and optical properties. Coating of the titanium nitride core reduces its oxidation upon exposure to air, drastically improving the plasmonic response. Thin films realized using the core–shell structure show practically no change in reflectivity, even when the thin films are heated to 900 °C in an inert atmosphere. This study introduces a simple surface passivation scheme that enhances the functionality of the material, providing further confirmation of the potential of nitride-based plasmonic materials as high-quality refractory optical compounds for a broad range of applications. [ABSTRACT FROM AUTHOR]

III–V semiconductor nanocrystals are an important class of optoelectronic materials. However, the gas‐phase synthesis of these materials, especially of the stibnides, has been left relatively unexplored. In this study, we demonstrate the synthesis of free‐standing GaSb nanocrystals for the first time, using a novel gas‐phase process. We show that when elemental aerosols are used as precursors for Ga and Sb, the elements mix at the nanometer length scale as the aerosols pass through a nonequilibrium plasma reactor. At sufficiently high plasma power, the mixing produces free‐standing GaSb nanocrystals, with a small amount of excess Ga segregated at the periphery of the particles. The reaction is initiated by vaporization of elemental aerosols in the plasma despite the low‐background temperature. Ion bombardment determines the extent of vaporization of Ga and Sb and thereby controls the ensemble stoichiometry and reaction rates. [ABSTRACT FROM AUTHOR]

A prior prediction of oxides of nitrogen, i.e., NOX (sum of NO and NO2), in diesel exhaust while treating with electric discharge-based nonthermal plasma (NTP) technique, would assist the researchers in planning the resources required for the treatment. In this present study, the performance of different regression-based models, i.e., linear, support vector regression and Gaussian process regression (GPR), has been analyzed for predicting the NOX concentrations based on the values of five dominating parameters of the NTP treatment. Experiments have been conducted and collected a dataset of 4032 number of input–output pairs to be used for training and testing of the regression models. The performances of these models have been assessed while testing them for the unseen set of data. A comparison of root-mean-square error (RMSE) has been made, where Matern 3/2 type of GPR model has been found to be the best among all the considered models with an RMSE of 1.86 ppm for a test data of 1210 sets. The model is shown to perform consistently well even when the test data are increased to 50% of total data. Regression analysis shows that the NOX can be predicted with very good accuracy using the Matern 3/2 type of GPR model. [ABSTRACT FROM AUTHOR]

We propose a pretreatment method for monosilane (SiH4) gas by high‐density plasma toward the relatively low‐temperature formation (≤600°C) of a crystalline Si film by thermal chemical vapor deposition (TCVD). SiH4 reaction behaviors with the plasma are investigated by using gas‐phase Fourier‐transform infrared spectroscopy. The dependence of the Si2H6 formation characteristics on total gas flow rate and input microwave power is examined. Si2H6 gas yields with the plasma treatment for SiH4 gas increased with decreasing input microwave power and increased with increasing total gas flow rate. Si films are prepared by TCVD using the plasma‐treated SiH4 gas. As a result, the pretreatment for SiH4 gas by high‐density plasma affects not only the deposition rate but also the crystallinity of the obtained Si film. The mechanism by which Si film formation is improved by plasma treatment is discussed. [ABSTRACT FROM AUTHOR]

Fungal infections induced by Candida albicans have increased worldwide due to emerging resistance to antifungal agents, which is largely caused by biofilm formation. Thus, a new and effective antimicrobial strategy is urgently required in treatment of C. albicans biofilm‐associated infections. In this study, the inactivation effects of cold plasma treatment for C. albicans biofilm are assessed in vitro and in vivo. In vitro studies indicate that C. albicans in suspension and the C. albicans biofilm are inactivated significantly by plasma treatment. In vivo studies indicate that plasma treatment achieves the best antifungal effect with an optimal dose (4 min in this case), as excessive plasma treatment damages the normal tissues and thus induces aggravation of infection compared to the 4‐min group. [ABSTRACT FROM AUTHOR]

Collagen coating of polystyrene (PS) labware involves a multistep process with high costs and complexity. Nonthermal plasma processes have recently been found to deposit coagulated and biologically functional protein layers in a single process step. A series of investigations were, therefore, conducted to compare plasma‐deposited collagen to an equivalent commercially coated product. Chemical and microscopic analysis suggests that the plasma‐deposited collagen retains the surface morphology and functional chemistry of the traditional collagen coating. Cell‐culture studies using two separate cell lines confirmed that the plasma‐deposited materials replicated the cell viability, proliferation and activity of the traditional collagen surfaces and outperformed uncoated PS plates. The implications of this for the protein coating of plastic labware surfaces are discussed. [ABSTRACT FROM AUTHOR]

As a novel sterilization technology, nonthermal plasma (NTP) has attracted a lot of attention. However, it could induce microorganisms into a viable but nonculturable (VBNC) state, posing a potential risk to food safety and public health. In this study, the molecular mechanisms of VBNC Staphylococcus aureus induced by NTP was investigated. With the use of a propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) technique combined plate count method, we confirmed that 8.1~24.3 KJ NTP induced S. aureus into a VBNC state at a level of 7.4 to 7.6 log10 CFU/mL. The transcriptomic analysis was conducted and revealed that most energy-dependent physiological activities (e.g., metabolism) were arrested in VBNC S. aureus, while the oxidative stress response-related genes (katA, dps, msrB, msrA, trxA) were significantly up regulated. In addition, this study showed that the ATP depletion by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) pretreatment could accelerate the formation of VBNC S. aureus. The NTP generated oxidative stress triggers the staphylococcal oxidative stress response, which consumes part of cellular energy (e.g., ATP). The energy allocation is therefore changed, and the energy assigned for other energy dependent physiological activities (cell growth and division, etc.) is reduced, subsequently forcing S. aureus into a VBNC state. Therefore, the alterations of energy allocation should be one of major contributors to the induction of VBNC S. aureus with NTP exposure. This study provides valuable knowledge for controlling the formation of VBNC S. aureus during NTP treatment. [ABSTRACT FROM AUTHOR]

Microwave plasma technology is revolutionizing reaction engineering fields such as methane dry reforming, chemical synthesis, biomass conversion, and waste treatment. Microwave generated plasma offers sustainable, cleaner and efficient operations compared to conventional methods. Microwave plasma reactions are more efficient when integrated with catalysts. In this article, a thorough categorization and comparison of microwave plasma-assisted catalytic reactions are presented, while highlighting their contribution to an energy efficient and sustainable future in chemical processing. An introduction on commercial applications of microwave plasma technology is also presented to emphasize its advantages in modern industries. Microwave irradiation can be used as a source of heat or plasma. The addition of heterogeneous catalyst to either microwave heated or microwave enhanced plasma systems can lead to complex pathways in reaction systems. A final section in this article is dedicated to comprehend this complexity in chemical reactions occurring in microwave heated and microwave plasma-enhanced catalytic systems. [ABSTRACT FROM AUTHOR]

As NOx and SOx have significant environmental impacts, advanced treatments are required to remove them from the exhaust gas of a glass melting furnace. Here, we investigate a plasma-chemical hybrid process (PCHP) for this purpose. A pilot-scale experiment of the simultaneous removal of NOx and SOx using a PCHP combined with the existing semi-dry type desulfurization reactor is conducted on actual high-temperature exhaust gas from a glass melting furnace. NO (the majority of NOx exist as NO) in the exhaust gas is oxidized to NO2 using active oxygen (ozone: O3) generated by a plasma ozonizer. The exhaust gas must be cooled to less than 150 °C in order to suppress the thermal decomposition of O3, while the gas temperature at the outlet of the semi-dry reactor must be kept at 200–;250 °C to protect the dry-type electrostatic precipitator. Therefore, it is important to form a local cooling area for NO oxidation in the reactor. In this article, we use the three-fluid nozzles of O3, water, and air to form the local cooling area and effectively oxidize NO to NO2. In addition, we spray NaOH aqueous solution for SO2 absorption downstream of the NO oxidation area to allow sufficient time for NO oxidation. The SO2 reacts with NaOH to produce Na2SO3, a powerful reducing agent. Subsequently, NO2 reacts with Na2SO3 and is reduced to N2, and the Na2SO4 generated in this reaction is reused as a clarifier of the raw materials for glass manufacturing. As a result, the ratio of the amount of removed NO and NOx to the amount of injected O3 (de-NO/O3 and de-NOx/O3) is 64% and 78%, respectively; therefore, high efficiency is obtained. This article includes actual examples of the treatment of exhaust gas in a glass melting furnace, using PCHP de-SOx and de-NOx technologies along with results from pilot-scale experiments. [ABSTRACT FROM AUTHOR]

Nonthermal processing methods are often preferred over conventional food processing methods to ensure nutritional quality. Nonthermal plasma (NTP) is a new field of nonthermal processing technology and seeing increased interest for application in food preservation. In food applications of NTP, liquid interactions are the most prevalent. The NTP reactivity and product storability are altered during this interaction. The water activated by NTP (plasma‐activated water [PAW]) has gained considerable attention during recent years as a potential disinfectant in fruits and vegetable washing. However, detailed understanding of the interactions of NTP reactive species with food nutritional components in the presence of water and their stability in food is required to be explored to establish the potential of this emerging technology. Hence, the main objective of this review is to give a complete overview of existing NTP–liquid interactions. Further, their microbial inactivation mechanisms and the effects on food quality are discussed in detail. Most of the research findings have suggested the successful application of NTP and PAW for microbial inactivation and food preservation. Still, there are some research gaps identified and a complete analysis of the stability of plasma reactive species in food is still missing. By addressing these issues, along with the available research output in this field, it is possible that NTP can be successfully used as a food decontamination method in the near future. [ABSTRACT FROM AUTHOR]

The effect of multiple sublethal doses of non-thermal plasma treatments on fungal cells phenotypical changes and the reduction in phytopathogenicity of Fusarium oxysporum , Botrytis cinerea, and Alternaria alternata was examined. The intensity of these changes depended on the species of fungus and the number of exposures of the mycelia to the DBD plasma. Microscopic observations showed that the plasma damaged the surface of the hyphae, increased their thickness and decreased overall dry biomass of the organisms. A decrease in pectinolytic activity was found in F. oxysporum and A. alternata , in contrast to B. cinerea , where an increase in pectinolytic activity was observed after the fifth plasma treatment. Changes in specific xylanase activity varied and were dependent on the species of fungus. The percentage of cucumber seeds germinated artificially infected with mycelium after multiple plasma treatments increased compared to those that were mycelium infected prior to plasma exposure. Plants that developed from seeds after plasma exposure were characterized by a higher biomass and longer roots and stems. Multiple treatments of the studied fungi with plasma, followed by seed infection, increased the SWVI and SWVI indexes of cucumber seedlings, but they did not reach the characteristic value of the control seeds (not infected with fungi). The reduced phytopathogenicity of the tested fungi was confirmed by artificial infestation of tomato fruits. • Nonthermal plasma effectively destroys phytopathogenic fungi. • Multiple treatments of the mycelium with plasma cause a reduction in pathogenicity. • Phenotypic changes in fungal cells are the result of multiple exposures to plasma. [ABSTRACT FROM AUTHOR]

• Plasma actuator using magnetic fluid as an electrode. • Plasma actuator with electrode arrangement controllable by a magnetic field. • Ionic wind generation using different electrode configurations investigated. • Ozone generation with different electrode configurations investigated. • Efficient ionic wind generation. Plasma actuators are compact wind power generators without mechanical power mechanisms. Plasma actuators have been investigated and developed. In a previous study of the authors, a single dielectric barrier discharge (DBD) plasma actuator using magnetic fluid (MF), termed "MF-DBD plasma actuator," was proposed for application to fanless air purification devices that can collect low-resistive particulate matter, such as diesel particulate, by electrostatic force without re-entrainment. The fundamental characteristics of the MF-DBD plasma actuator, such as ionic wind, temperature distribution, and ozone and ion concentrations, were investigated in the previous study. The advantage of an MF-DBD plasma actuator is that the position and shape of the MF electrode can be controlled using a magnetic field. In view of this advantage, in this study, ionic wind and ozone generation in a single MF-DBD plasma actuator with different electrode configurations is investigated for the future development of MF-DBD plasma actuators and their application in fanless air purification. In these experiments, the width of the insulated electrode and the distance between the exposed and insulated electrodes are varied. As a result, in the case of a constant applied voltage, the ionic wind velocity and ozone concentration depend only on the overlap between the magnetic fluid and the insulated electrode, and these values increase as the overlap increases. It is clarified that a large overlap between the MF and insulated electrodes can generate an efficient ionic wind in terms of wind velocity and energy consumption. [ABSTRACT FROM AUTHOR]

• Plasma partial oxidative reforming of the tar model compound was carried out. • A detailed kinetics model was established based on the calculated G-values of active species. • Performance was evaluated under pure N 2 and gasification gas atmospheres. • The highest toluene conversion was 100.0 % with an energy efficiency of 25.7 g/kWh, without catalysts usage. In this study, partial oxidation of toluene as a biomass tar surrogate was carried out in a dielectric barrier discharge (DBD) plasma reactor. In order to understand the reaction characteristics and thus potential of the approach, the effect of reaction temperature, O 2 /toluene molar ratio (OTR) and discharge power on performances was investigated by experiments and kinetic modeling. The results showed that the three factors could change the E/n and hence the G-values of species, as well as alter O 2 concentration in background gas and input energy, leading to the variation in active species production and thus, the performance. Appropriate high temperatures, as well as higher OTRs and discharge power obtained better performances by promoting toluene destruction and gas product production. Excited N 2 species play a crucial role in the process, by means of participating in reactions directly and strongly influencing on the production of secondary active species. At 300 °C, the highest toluene conversion of 100.0 % with an energy efficiency of 25.7 g/kWh was achieved without catalysts usage, a comparable performance as compared to the steam reforming by plasma catalysis, demonstrating the potential of this method for the purification of gasification gases. Furthermore, based on the rate of production (ROP) and sensitivity analyses of the model developed, as well as experimental results, the reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Although nonthermal plasma (NTP) technology has high removal efficiency for volatile organic compounds (VOCs), it has limited carbon dioxide (CO 2) selectivity, which hinders its practical application. In this study, α-MnO 2 nanorods with tunable oxygen vacancies and hydroxyl groups were synthesized by two-step hydrothermal process to enhance their activity for deep oxidation of toluene. Hydrochloric acid (HCl) was used to assist in synthesis of α-MnO 2 nanorods with tunable oxygen vacancies, furtherly, more hydroxyl groups were introduced to HCl-assisted synthesized α-MnO 2 by K+ supplement. The results showed that the as-synthesized nanorods exhibited superior activity, improved by nearly 30% removal efficiency of toluene compared to pristine MnO 2 at SIE = 339 J/L, and reaching high CO x selectivity of 72% at SIE = 483 J/L, successfully promoting the deep oxidation of toluene. It was affirmed that oxygen vacancies played an important role in toluene conversion, improving the conversion of ozone (O 3) and resulting in higher mobility of surface lattice oxygen species. Besides, the enhancement of deep oxidation performance was caused by the increase of hydroxyl groups concentration. In-situ DRIFTS experiments revealed that the adsorbed toluene on catalyst surface was oxidized to benzyl alcohol by surface lattice oxygen, and hydroxyl groups were also found participating in toluene adsorption. Overall, this study provides a new approach to designing catalysts for deep oxidation of VOCs. [Display omitted] • α-MnO 2 nanorods with tunable oxygen vacancies and hydroxyl groups were synthesized. • Hydrochloric acid assisted synthesis of α-MnO 2 raised oxygen vacancy concentration. • Oxygen vacancy facilitated toluene conversion performance. • Generation of hydroxyl groups by K+ supplement enhanced CO 2 selectivity. [ABSTRACT FROM AUTHOR]

Nonthermal plasma treatment has been proven effective in decontaminating microorganisms in various foods on a laboratory scale. Various techniques for creating plasma have been investigated extensively due to their potential application in multiple settings; one of these methods is dielectric barrier discharge. This article summarizes our current understanding of plasma physics, different methods for producing plasma, the resulting reactive species, and their role in microbial degradation. The effect of plasma treatment on the inactivation of microorganisms is discussed, along with the intrinsic and extrinsic factors involved. In addition, the use of dielectric barrier discharge plasma in microbial destruction in various foods, as well as the effect of the treatment on other relevant properties, is also addressed. [ABSTRACT FROM AUTHOR]

Cold plasma technology has received significant attention in agriculture due to its effect on the seeds and plants of important cultivars, such as wheat. Due to climate change, wherein increasing temperatures and droughts are frequent, it is important to consider novel approaches to agricultural production. As increased dormancy levels in wheat are correlated with high temperatures and drought, improving the germination and root growth of wheat seeds could offer new possibilities for seed sowing. The main objective of this study was to evaluate the influence of direct (glow) and indirect (afterglow) radio-frequency (RF) oxygen plasma treatments on the germination of two winter wheat varieties: Apache and Bezostaya 1. The influence of plasma treatment on seed surface morphology was studied using scanning electron microscopy, and it was observed that direct plasma treatment resulted in a high etching and nanostructuring of the seed surface. The effect of plasma treatment on germination was evaluated by measuring the germination rate, counting the number of roots and the length of the root system, and the fresh weight of seedlings. The results of this study indicate that the response of seeds to direct and indirect plasma treatment may be variety-dependent, as differences between the two wheat varieties were observed.

The increasing use of functional aramids in a wide array of applications and the inert nature of aramids against conventional dye and print methods requires developing new dyeing methods. This study aims to use environmentally friendly method with a cationic dye as an alternative for dyeing para-aramid fabrics. Experiments used a multi-factorial design with functions of pretreatment, dye solvent (water and/or glycerol) and auxiliary chemical additives (swelling agent and surfactant) and a sequential experimentation methodology. The most effective dyeing procedures involved the following steps: (i) pretreatments of the fabrics with soybean oil and nonthermal plasma (NTP), (ii) using water at T = 100 °C as the dye solvent, and (iii) omitting other chemical additives. With a commercial cationic dye, these conditions achieved a color strength in K/S value of 2.28, compared to ~1 for untreated samples. FTIR analysis revealed that a functional network formed on the fibers and yarns of the fabrics by chemical reactions of excited plasma species with double bonds in the soybean oil molecules was responsible for significantly improving the color strength. These results extend the potential uses of a renewable material (soybean oil) and an environmentally friendly technology (NTP) to improve the dyeing of para-aramid textiles and reduce the use of harsh dye chemicals.

Combination therapies for the treatment of oral squamous cell carcinoma have been studied extensively and represent a synergistic approach with better outcomes than monotherapy. In this study, a novel combination therapy was investigated using gold nanoparticles (GNP) conjugated to programmed cell death protein ligand 1 (PD-L1) antibodies and nonthermal plasma (NTP). The present study describes the effectiveness of NTP using PD-L1 antibody conjugated to GNP in PD-L1 expressing SCC-25 cells, an oral squamous cell carcinoma line. Immunocytochemistry revealed higher levels of PD-L1 expression and an increase in the selective uptake of PD-L1 antibody + GNP on SCC-25 cells compared to HaCaT cells. In addition, cell viability analyses confirmed higher levels of cell death of SCC-25 cells after treatment with PD-L1 antibody, GNP, and NTP compared to HaCaT cells. Among the experimental groups, the highest cell death was observed upon treatment with PD-L1 antibody + GNP + NTP. Following the Western blot analysis and immunofluorescence staining, the expression of apoptosis-related proteins was found to increase after treatment with PD-L1 antibody + GNP + NTP among the other experimental groups. In conclusion, the treatment of SCC-25 cells with PD-L1 antibody + GNP + NTP significantly increased the number of dead cells compared to other experimental groups. The results of this in vitro study confirmed the therapeutic effects of PD-L1 antibody + GNP + NTP treatment on oral squamous cell carcinoma.

This Special Issue, entitled “Plasma Medicine Technologies”, covers the latest remarkable developments in the field of plasma bioscience and medicine. Plasma medicine is an interdisciplinary field that combines the principles of plasma physics, material science, bioscience, and medicine, towards the development of therapeutic strategies. A study on plasma medicine has yielded the development of new treatment opportunities in medical and dental sciences. An important aspect of this issue is the presentation of research underlying new therapeutic methods that are useful in medicine, dentistry, sterilization, and, in the current scenario, that challenge perspectives in biomedical sciences. This issue is focused on basic research on the characterization of the bioplasma sources applicable to living cells, especially to the human body, and fundamental research on the mutual interactions between bioplasma and organic–inorganic liquids, and bio or nanomaterials.

Polycrystalline Ni, Pd, Cu, Ag, and Au foils exposed to nonthermal plasma (NTP)-activated N 2 are found to exhibit a vibrational feature near 2200 cm -1 in polarization-modulation infrared reflection-absorption spectroscopy (PM-IRAS) observations that are not present in the same materials exposed to N 2 under nonplasma conditions. The feature is similar to that reported elsewhere and is typically assigned to chemisorbed N 2 . We employ a combination of temperature-dependent experiments, sequential dosing, X-ray photoelectron spectroscopy, isotopic labeling, and density functional theory calculations to characterize the feature. Results are most consistent with a triatomic species, likely NCO, with the C and O likely originating from ppm-level impurities in the ultrahigh-purity (UHP) Ar and/or N 2 gas cylinders. The work highlights the potential for nonthermal plasmas to access adsorbates inaccessible thermally as well as the potential contributions of ppm-level impurities to corrupt the interpretation of plasma catalytic chemistry.

Nanoscale metallic titanium (Ti) offers unique energetic and biocompatible characteristics for the aerospace and biomedical industries. A rapid and sustainable method to form purified Ti nanocrystals is still in demand due to their high oxygen affinity. Herein, we report the production of highly purified Ti nanoparticles with a nonequilibrium face center cubic (FCC) structure from titanium tetrachloride (TiCl 4 ) via a capacitively coupled plasma (CCP) route. Furthermore, we demonstrate a secondary H 2 treatment plasma as an effective strategy to improve the air stability of a thin layer of nanoparticles by further removal of chlorine from the particle surface. Hexagonal and cubic-shaped Ti nanocrystals of high purity were maintained in the air after the secondary H 2 plasma treatment. The FCC phase potentially originates from small-sized grains in the initial stage of nucleation inside the plasma environment, which is revealed by a size evolution study with variations of plasma power input.

Few investigations have tested the practical use of cold plasma as a novel technology to meet the requirements in the plant cell and tissue culture field. To fill the knowledge gap, we intend to respond to the question of whether plasma priming influenced DNA ultrastructure and the production of atropine (a tropane alkaloid) in Datura inoxia. Calluses were treated with the corona discharge plasma at time durations ranging from 0 to 300 s. Significant increases (about 60%) in biomass were observed in the plasma-primed calluses. The plasma priming of calluses enhanced the accumulation of atropine about 2-fold. The plasma treatments increased proline concentrations and soluble phenols. The drastic increases in the activity of the phenylalanine ammonia-lyase (PAL) enzyme resulted from the applied treatments. Likewise, the plasma treatment of 180 s upregulated the expression of the PAL gene by 8-fold. Also, the expression of the ornithine decarboxylase (ODC) and tropinone reductase I (TR I) genes were stimulated by 4.3-fold and 3.2-fold, respectively, in response to the plasma treatment. The putrescine N-methyltransferase gene displayed a similar trend to that of TR I and ODC genes following the plasma priming. Methylation sensitive amplification polymorphism method was employed to explore the plasma-associated epigenetic changes in DNA ultrastructure. The molecular assessment referred to DNA hypomethylation, validating an epigenetic response. This biological assessment study validates the hypothesis that plasma priming of callus is an efficient, cost-effective, and eco-friendly tool to enhance callogenesis efficiency, elicit metabolism, affect gene regulation, and modify chromatin ultrastructure in D. inoxia., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Forward feed multilayered perception and central composite rotatable design were used to model the nonthermal plasma (NTP) experimental data in artificial neural network (ANN) and response surface methodology, respectively. The ANN was found to be more accurate in modeling the experimental dataset. The NTP process parameters (voltage and time) were optimized for pineapple juice within the range of 25-45 kV and 120-900 s using an ANN coupled with the genetic algorithm (ANN-GA). After 176 generations of GA, the ANN-GA approach produced the optimal condition, 38 kV and 631 s, and caused the inactivation of peroxidase (POD) and bromelain by 87.24% and 51.04%, respectively. However, 100.32% of the overall antioxidant capacity and 89.96% of the ascorbic acid were maintained in the optimized sample with a total color change (ΔE) of less than 1.97 at all plasma treatment conditions. Based on optimal conditions, NTP provides a sufficient level of POD inactivation combined with excellent phenolic component extractability and high antioxidant retention. Furthermore, plasma treatment had an insignificant effect (p > 0.05) on the physicochemical attributes (pH, total soluble solid, and titratable acidity) of juice samples. From the intensity peak of the Fourier-transform infrared spectroscopy analysis, it was found that the sugar components and phenolic compounds of plasma-treated juice were effectively preserved compared to the thermal-treated juice., (© 2023 Institute of Food Technologists.)

The feasibility of fabricating better solid acid catalysts using nonthermal plasma (NTP) technology for biobased acrolein production is demonstrated. NTP discharge exposure was integrated in catalyst fabrication in air or argon atmosphere. The fabricated catalysts were characterized by Brunauer–Emmett–Teller surface area analysis, temperature-programmed desorption of ammonia, X-ray powder diffraction and Fourier-transform infrared spectroscopy of pyridine adsorption, in comparison to regularly prepared catalysts as a control. Further, kinetic results collected via glycerol dehydration experiments were compared, and improvement in acrolein selectivity was displayed when the catalyst was fabricated in the argon NTP, but not in the air NTP. Possible mechanisms for the improvement were also discussed.

• PM low-temperature decomposition assisted by NTP technology has been tested. • The SOF proportion declined, and the DS proportion of PM increased. • New oxygen-containing functional groups (C O) were generated as intermediates. • High-carbon-atom-number components becamelow-carbon-atom-number components. • NTP can improve PM oxidizing activity and promote low-temperature combustion of PM. Nonthermal plasma (NTP) technology can oxidize and decompose diesel particulate matter (PM) under much lower temperatures (≤200 °C), showing promise for potential applications. A test bench for the treatment of diesel PM using an NTP injection system was constructed, and PM samples before and after NTP reaction were accumulated on filter papers. The apparent morphology, oxidative activity, surface functional groups, and soluble organic fractions (SOF) components of PM samples were investigated using modern techniques (i.e., SEM, TGA, FT-IR, and GC–MS). Results show that after NTP reactions, the amount of PM declined substantially and the surface stacking structure became relatively smooth; the proportion of SOF reduced and that of DS increased. Carbon atoms and functional groups on the edge or surface of the carbon layer were first oxidized by the NTP active substance (O 3 , O) to form CO or CO 2 , causing carbon atoms to fall off the original bond and new oxygen-containing functional groups to be generated as intermediates. After the NTP reaction, the oxidation characteristic temperatures decreased and high-carbon-atom-number components were transformed into low-carbon-atom-number components. Results reveal that NTP can improve PM oxidizing activity and promote low-temperature combustion of PM; PM decomposition can be regarded as a process of constantly removing carbon atoms. [ABSTRACT FROM AUTHOR]

Recently, plasma activated water (PAW) has drawn huge attention because it is considered to be useful for biomedical and agricultural applications. Because the PAW contains several nitrogen compounds such as nitrate, it can be used as a natural fertilizer. In this article, we report the comparative test results of PAW production by combining nonthermal plasma, thermal plasma, and hybrid methods. As a thermal plasma source, gas-jet assisted pulsed discharge (GAPD) under water was used, and the coaxial cylindrical dielectric barrier discharge (DBD) was adopted as the nonthermal plasma source. The difference in the radical generation rate between the two methods was identified. Some synergy effects in the formation of nitrate ion by the hybrid system were also confirmed. It is considered that the surface discharge through the air channel in GAPD formed by the gas jet stabilized more rapidly by increasing the conductivity of water by relatively high power DBD. This combination can greatly improve the energy efficiency of nitric acid production at relatively low input energies. [ABSTRACT FROM AUTHOR]

Diesel exhaust treatment in plasma environment is a complex phenomenon mainly involving oxidation of several gaseous pollutants. With the help of artificial neural network, an attempt has been made in this paper to predict the variation of nitric oxide/nitrogen dioxide when the exhaust is subjected to discharge plasma. Electrical (power and frequency) and physical (engine load and flow rate) parameters have been considered as inputs of a three-layered artificial neural network model to track the performance of the treatment. Two different backpropagation algorithms named Bayesian regularization and Levenberg–Marquardt have been applied to compare the prediction performance. Bayesian regularization training algorithm shows better agreement with the experimental data than Levenberg–Marquardt in terms of root-mean-square error and correlation coefficient. Further, sensitivity analysis has been carried out to obtain an insight about the relative importance of input parameters on output parameters. This investigation shows that the applied input power is the most influential among the four input parameters from the point of variation of nitric oxide/nitrogen dioxide. [ABSTRACT FROM AUTHOR]

The ion acoustic nonlinear periodic (cnoidal) waves are studied in an unmagnetized plasma consisting of cold ions and nonthermal electrons following Cairns distribution. By employing reductive perturbation method, the nonlinear Korteweg-de Vries (KdV) and modified Korteweg-de Vries (mKdV) equations are derived, and their periodic wave solutions are obtained and analyzed numerically. It has been pointed that the KdV equation fails at plasma critical composition, and we have thus taken into account the higher order nonlinearity and derived the mKdV equation. In the latter case, the coexistence of compressive and rarefactive periodic wave structures is pointed out in the critical case. So far, this aspect has not been tackled at all in the nonthermal plasma literature on periodic waves. In the present work, it is the degree of nonthermality of electrons that is responsible for the rarefactive solutions. The present plasma model accounts for the cnoidal wave structures (Jovanovic and Shukla Phys. Rev. Lett. 84, 4373 2000) in the magnetosphere observed via FAST and POLAR spacecrafts. [ABSTRACT FROM AUTHOR]