Search Results (21)

Nanometals constitute a rapidly growing area of research within nanotechnology. Nanosilver and nanogold exhibit significant antimicrobial, antifungal, antiviral, anti-inflammatory, anti-angiogenic, and anticancer properties. The size and shape of nanoparticles are critical for determining their antimicrobial activity. In this study, silver and gold nanoparticles were synthesized within a hyaluronic acid matrix utilizing distilled water and distilled water treated with low-pressure, low-temperature glow plasma in an environment of air and argon. Electron microscopy, UV-Vis and FTIR spectra, water, and mechanical measurements were conducted to investigate the properties of nanometallic composites. This study also examined their microbiological properties. This study demonstrated that the properties of the composites differed depending on the preparation conditions, encompassing physicochemical and microbiological properties. The application of plasma-treated water under both air and argon had a significant effect on the size and distribution of nanometals. Silver nanoparticles were obtained between the range of 5 to 25 nm, while gold nanoparticles varied between 10 to 35 nm. The results indicate that the conditions under which silver and gold nanoparticles are produced have a significant effect on their mechanical and antibacterial properties. Full article

In recent years, the production of plasma-treated water (PTW) by low-temperature low-pressure glow plasma (LPGP) has been increasingly gaining in popularity. LPGP-treated water changes its physical and physiochemical properties compared to standard distilled water. In this study, a non-conventional lipolytic yeast species Yarrowia lipolytica was cultivated in culture media based on Nantes plasma water with heightened singlet oxygen content (Nantes PW) or in water treated with low-temperature, low-pressure glow plasma while in contact with air (PWTA) or nitrogen (PWTN). The research aimed to assess the influence of culture conditions on castor oil biotransformation to gamma-decalactone (GDL) and other secondary metabolites in media based on nanowater. The Nantes plasma water-based medium attained the highest concentration of gamma-decalactone (4.81 ± 0.51 g/L at 144 h of culture), maximum biomass concentration and biomass yield from the substrate. The amplified activity of lipases in the nanowater-based medium, in comparison to the control medium, is encouraging from the perspective of GDL biosynthesis, relying on the biotransformation of ricinoleic acid, which is the primary component of castor oil. Although lipid hydrolysis was enhanced, this step seemed not crucial for GDL concentration. Interestingly, the study validates the significance of oxygen in β-oxidation enzymes and its role in the bioconversion of ricinoleic acid to GDL and other lactones. Specifically, media with higher oxygen content (WPTA) and Nantes plasma water resulted in remarkably high concentrations of four lactones: gamma-decalactone, 3-hydroxy-gamma-decalactone, dec-2-en-4-olide and dec-3-en-4-olide. Full article

This comprehensive review begins by tracing the historical development and progress of cold plasma technology as an innovative approach to polymer engineering. The study emphasizes the versatility of cold plasma derived from a variety of sources including low-pressure glow discharges (e.g., radiofrequency capacitively coupled plasmas) and atmospheric pressure plasmas (e.g., dielectric barrier devices, piezoelectric plasmas). It critically examines key operational parameters such as reduced electric field, pressure, discharge type, gas type and flow rate, substrate temperature, gap, and how these variables affect the properties of the synthesized or modified polymers. This review also discusses the application of cold plasma in polymer surface modification, underscoring how changes in surface properties (e.g., wettability, adhesion, biocompatibility) can be achieved by controlling various surface processes (etching, roughening, crosslinking, functionalization, crystallinity). A detailed examination of Plasma-Enhanced Chemical Vapor Deposition (PECVD) reveals its efficacy in producing thin polymeric films from an array of precursors. Yasuda’s models, Rapid Step-Growth Polymerization (RSGP) and Competitive Ablation Polymerization (CAP), are explained as fundamental mechanisms underpinning plasma-assisted deposition and polymerization processes. Then, the wide array of applications of cold plasma technology is explored, from the biomedical field, where it is used in creating smart drug delivery systems and biodegradable polymer implants, to its role in enhancing the performance of membrane-based filtration systems crucial for water purification, gas separation, and energy production. It investigates the potential for improving the properties of bioplastics and the exciting prospects for developing self-healing materials using this technology. Full article

Theoretical and experimental investigations of the radial distribution function of the electron temperature (RDFT), for the abnormal glow region in a low-density plasma fluid and weakly ionized argon gas, are provided. The final proved equation of RDFT agrees with the experimental data for different low pressures ranging from 0.2 to 1.2 torr, confirming that the electron temperatures decrease with an increasing product of radial distance (R) and gas pressures (P). A comparison of the two configurations: $\mathrm{R}>\mathrm{L} \mathrm{and} \mathrm{L}>\mathrm{R},$ for the axial distance (L), from the tip of the single probe to the cathode electrode, and the cathode electrode radius (R), shows that, in both cases, the generated plasma temperatures decrease, and densities increase. The RDFT accurately depicts a dramatic decrease for L < R by 60% compared with the values for L > R. This indicates that, when L < R, the rate of plasma loss by diffusion is reduced. Under this investigation, the mechanical characteristics of treated and pre-treated Ihram Cotton Fabric Samples were compared under the Influence of the different two configurations of Plasma Cell discharge: $\mathrm{R}>\mathrm{L}>\mathrm{R}$. These characteristics included resiliency, strain hardening, tensile strength, elongation percentage, yield strength, ultimate tensile strength, toughness, and fracture (breaking) point. Furthermore, the mechanism parameters of plasma interaction with textile membrane will be discussed, such as: process mechanism, interaction, and gas type. Full article

Yeast plays a key role in the production of alcoholic beverages. Effective fermentation requires appropriate conditions to ensure the production of high-quality beer. The paper discusses the effect of dry brewing yeast (Saccharomyces cerevisiae and Saccharomyces pastorianus) after rehydration with water exposed to low-temperature, low-pressure glow plasma (PTW) in the atmosphere of air (PTWAir) and nitrogen (PTWN) in the course of the fermentation process, the formation of volatile compounds and other quality parameters of the finished beer. The obtained results show that the lager yeast strain initiated the process of fermentation faster after rehydration in the presence of PTWAir compared to all of the other treatments. It was observed that PTWAir significantly changed the composition of volatile compounds in the finished beer, especially by increasing the number of terpenes, which are compounds that positively shape the aroma of beer. In the case of PTWN samples, lower alcohol content, real extract, apparent extract and amount of biomass were observed in all analyzed strains. Full article

The increasing popularity of active dry yeast arises from its properties, such as ease of storage, and simplicity of preparation and dosing. Herein, we elaborate on the effect of plasma-treated water (PTW) under air atmosphere (PTWAir) and nitrogen (PTWN) on the improvement of the reserve polysaccharide glycogen level and other quality parameters of S. cerevisiae brewing dry yeast in comparison with the non plasma-treated water (CW). For this purpose, strains of top-fermenting (S. cerevisiae T58 (poor quality), S33 (poor quality)) and bottom-fermenting (S. pastorianus W30/70 (poor quality)) yeast stored one year after opening and S. cerevisiae US-05 (fresh strain) were selected to examine the influence of PTWs toward the quality parameters of yeast biomass after the rehydration and fermentation process. The obtained results showed that in the case of poor quality yeast strains, PTWAir increased glycogen content after the rehydration and fermentation process, which was a favorable trend. A similar increase was observed for the trehalose content. Results showed that PTWN significantly reduced the number of yeast cells in ale strains and the viability of all analyzed samples. The lowest viability was observed in Sc S33 strain for PTWAir (41.99%), PTWN (18.6%) and CW (22.86%). PTWAir did not contribute to reducing the analyzed parameter; in particular, the results of Sc T58 yeast strain’s viability are shown: PTWAir (58.83%), PTWN (32.28%) and CW (43.56%). The obtained results suggest that rehydration by PTWN of dry yeast with a weakened condition is not recommended for both qualitative and cost-related reasons, while PTWAir significantly contributed to the improvement of some yeast parameters after rehydration and fermentation (higher glycogen and trehalose content). Full article

Recently, a series of papers reported preparation and physicochemical properties of various kinds of water treated in contact with various gases with low-temperature, low-pressure glow plasma of low frequency (LPGP). Consecutive papers presented results of watering numerous herbal plants with those kinds of water in planting of numerous herbal plants. Always, the watering influenced the yield and quality of the crops and considerably changed the composition of the essential oils extracted from the watered plants. This paper provides the effects of watering of Cannabis sativum var. Finola with water LPGP-treated either in the air (LPGPA), under molecular nitrogen (LPGPN) or carbon dioxide (LPGPC). Cannabis sativa, particularly its botanic class called hemp, attracts great attention for its numerous applications. They include rope, textiles, clothing, shoes, food, paper, bioplastics, insulation, biofuel and industrial fibre. The watering was maintained for 12 weeks. Regardless of the kind of the used plasma-treated water, a considerable increase in the plant crop yield was noted for first 7 weeks. Further cultivation resulted in a minute increase in the yield. The watering with LPGPC offered the highest crop yield, followed by nontreated water, LPGPN and LPGPA. The yield of essential oil per 1 g of plant was independent of the used kind of plasma-treated water. Watering Finola with LPGPA resulted in a decrease in the level of cannabidivarin (CBD V) and considerable increase in the deal of Δ 9-tetrahydrocannabinol (Δ⁹-THC). The levels of the remaining components of the essential oil slightly decreased with respect to that in the control sample. Almost identical trends in the influence of watering upon the composition of essential oil were observed in the case of LPGPN. However, an unusually strong decrease in the level of CBD V accompanied by a very high increase in the level of Δ⁹-THC could be noted. The performed study provided strong evidence that watering seeds and plants of Finola with various kinds of the LPGP-treated water could modulate and even tailor the crop yield, functional properties of the plant and essential oils extracted from it. The composition of the essential oil isolated from the plant watered with LPGPN suggests its application as a substitute of medical marijuana (medical cannabis). Full article

Plasma processing is now a key technology across the world, and nonthermal low-temperature plasmas are being increasingly used. This situation can be explained by a rapidly growing interest in the optimization of existing methods, as well as the development of new ones. Over the last few years, the production of plasma-treated water (PTW) by low-temperature low-pressure glow plasma (LPGP) under an atmosphere of various gases has been increasingly gaining in popularity. Research has been conducted on producing plasma-treated water in the presence of air, nitrogen, ammonia, carbon dioxide, and methane. All the obtained results show that the changed physicochemical properties of the water depend on the type of gas used and the duration of the plasma treatment. New research is emerging on the possibility of using this water in plant breeding, animal husbandry, cosmetology, medicine, and food. For the first time, plasma-treated water has also been tested for use in the brewing industry at the raw material preparation stage. The results obtained in all branches of science are very promising, contributing to the growing interest in plasma-treated water within the scientific community. Full article

The nonlinear dust-acoustic instability in the condensed submicron fraction of dust particles in the low-pressure glow discharge at ultra-low temperatures is experimentally and theoretically investigated. The main discharge parameters are estimated on the basisof the dust-acoustic wave analysis. In particular, the temperature and density of ions, as well as the Debye radius, are determined. It is shown that the ion temperature exceeds the temperature of the neutral gas. The drift characteristics of all plasma fractions are estimated. The reasons for the instability excitation are considered. Full article

The aim of this paper is to investigate the process of growth of different carbon deposits in low-current electrical microdischarges in argon with an admixture of cyclohexane as the carbon feedstock. The method of synthesis of carbon structures is based on the decomposition of hydrocarbons in low-temperature plasma generated by an electrical discharge in gas at atmospheric pressure. The following various types of microdischarges generated at this pressure were tested for both polarities of supply voltage with regard to their applications to different carbon deposit synthesis: Townsend discharge, pre-breakdown streamers, breakdown streamers and glow discharge. In these investigations the discharge was generated between a stainless-steel needle and a plate made of a nickel alloy, by electrode distances varying between 1 and 15 mm. The effect of distance between the electrodes, discharge current and hydrocarbon concentration on the obtained carbon structures was investigated. Carbon nanowalls and carbon microfibers were obtained in these discharges. Full article

The low temperature plasma of glow discharge has found a widespread use as a heating source in welding and surface treatment of metals. The meticulous analysis of glow discharge’s instabilities in these processes allowed us to highlight the physicochemical characteristics of the cathode surface (the welded or treated samples) as one of the main reasons of its transition into an electric arc—as a more stable form of gas discharges. The prolonged arc action on the samples surfaces inevitably leads to the disruption of the technological process and, consequently, to undesirable overheating of samples. In this regard, the main aim of this work is to study the influence of the macro- and micro relief of the cathode on the stable glow discharge existence in the processes of metals treatment and diffusion welding. It has been analytically established and experimentally supported that the glow discharge’s stability is mainly affected by the sharp protrusions generated on the cathode surface because of samples pre-treatment by machining before welding. It has been established that the rough surface pre-treatment with the Rz about 60–80 µm decreases the pressure range of glow discharge sustainable existence from 1.33–13.3 kPa to 1.33–5.3 kPa compared with the surface machining with the Rz about 10 µm. Full article

Plantations of lovage, marjoram, rosemary and thyme were watered with water treated with low-temperature, low-pressure glow plasma of low frequency. Such watering appeared beneficial to the extent dependent on particular herb. In terms of crop yield and quality, water treated with glow plasma performed best in the case of rosemary, and the worst results were observed for thyme. When yield of essential oils are taken into account, only in the case of lovage did such watering appear beneficial, while in the remaining cases it had no effect. However, such watering considerably changed the composition of essential oils. These changes were specific for a given herb and involved the quantity of particular components of the oils. Only in the essential oil from lovage did γ-terpinene appear as its novel component. Full article

The effect of watering basil (Ocimum basilicum L.) with water treated with low-pressure, low-temperature glow plasma of low frequency (LPGP) on growth habits and plant metabolites was tested. Watering with the LPGP treated water was beneficial for sprouting basil seeds. Watering with non-treated water was advantageous solely for the number of leaves per plant and mass of one leaf. Watering with the LPGP treated water in contact with the air (LPGPA), nitrogen (LPGPN), carbon dioxide (LPGPC), and methane (LPGPM) increased the total yield of collected essential oil by 40%, 60%, 20%, and 20%, respectively. Watering with water treated under molecular oxygen (LPGPO) decreased that yield by 12.5%. A diverse effect of particular kinds of the LPGP treated water upon the composition of isolated essential oil was also noted. Full article

A low-temperature (400 °C) glow plasma nitriding layer on AISI 904L austenitic stainless steel was obtained at various NH₃ pressures and studied using electrochemical method, X-ray diffraction, and scanning Kelvin probe. The pressure of NH₃ dominated the microstructure of the nitriding layer. The saturation degree of γN controlled corrosion performance and microhardness. Insufficient NH₃ pressure (<100 Pa) resulted in discontinuous nitride caking coverage, whereas excessive NH₃ pressure (>100 Pa) facilitated the transformation of the nitriding layer to harmful nitrides (CrN) due to a localized overheating effect caused by the over-sputtering current. Full article

Lavandula angustifolia was watered with either deionized tap water treated with low-temperature, low-pressure glow plasma of low frequency in the air (LPGPA), under oxygen-free nitrogen (LPGPN), methane (LPGPM), carbon dioxide (LPGPC) or molecular oxygen (LPGPO). The crop yields were slightly dependent on the type of water used for watering. Notably, only plants watered with LPGPN showed a slightly higher crop yield. The plants also contained a higher level of protein and bioaccumulated magnesium. The type of water had a considerable and specific effect on the yield of isolated essential oils and their composition. The yield of essential oil decreased in the following order LPGPA = LPGPN (0.4 g/100 g dry mass) > LPGPC = LPGPO (0.3 g/100 g dry mass) > LPGPM = non-treated water (0.2 g/100 g dry mass). The composition of the isolated essential oils varied depending on the type of water used for watering, which influences their role as a fragrant component of cosmetics, and in herbal therapy and aromatherapy. Full article