77 results on '"Mozetič, M."'
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2. Gas Analyses of First complete JET Cryopump Regeneration with ITER-Like Wall
- Author
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Romanelli, S. Grunhagen, Brezinsek, S., Butler, B., Coad, J. P., Drenik, A., Giroud, C., Jachmich, S., Keenan, T., Kruezi, U., Mozetic, M., Oberkofler, M., Parracho, A., Romanelli, M., Smith, R., and contributors, JET EFDA
- Subjects
Physics - Instrumentation and Detectors - Abstract
Analytical results of a complete JET cryopump regeneration, including the nitrogen panel, following the first ITER-Like Wall campaign are presented along with the in-situ analyses of residual gas. H/D mixtures and impurities such as nitrogen and neon were injected during plasma operation in the vessel to study radiation cooling in the scrape-off-layer and divertor region. The global gas inventory over the campaign is incomplete, suggesting residual volatile impurities are remaining on the cryogenic panel. This paper presents results on a) residual deuterium on the panel which is related to the campaign very low, b) impurities like nitrogen which sticks on the panel and c) the ammonia production which can be observed in the RGA spectrum., Comment: 7 pages, 3 figures. This is an author-created, un-copyedited version of an article accepted for publication in Physica Scripta. IOP Publishing Ltd and IAEA are not responsible for any errors or omissions in this version of the manuscript or any version derived from it
- Published
- 2014
- Full Text
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3. RF wall conditioning at the Uragan-2M with use of high vacuum cryogenic trap
- Author
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Кorovin, V. B., Baron, D. I., Kozulya, M., Chernichenko, V., Kramskoy, E. D., Pashnev, V. K., and Mozetič, M.
- Subjects
Магнитное удержание - Abstract
The results of evaluating the effectiveness of the vacuum chamber wall conditioning procedure by the use VHF of continuous discharge and RF pulse discharge that were applied either separately or in combination with each other in helium atmosphere at Uragan-2M are presented. The high-vacuum cryogenic traps are enabled in these experiments. Some amount of gas pumped from the vacuum chamber is condensed on the surfaces of cryogenic traps integrated in the input branch pipes of the vacuum system. Periodically, one trap is separated from the chamber and from the pump by vacuum valves and warmed up what led to release of the condensed gases into the enclosed volume. The value of pressure Pg inside this volume is proportional to the amount of pumped gas and, consequently, to the effectiveness of the wall conditioning process. It was found that the value Pg in the combined VHF + RF discharge is 2-3 times higher than in the case of using only pulsed RF discharge. Приведены результаты ВЧ-чистки в стеллараторе Ураган-2М с использованием УКВ непрерывного разряда в атмосфере гелия. При этом часть откачиваемого газа конденсировалась на криогенную ловушку. Процесс чистки контролировался измерением давления газа Pг в отсеченном объеме с ловушкой после ее отепления. Значение Pг пропорционально количеству откачиваемого газа. Обнаружено, что количество сконденсированного на ловушке газа при комбинированном УКВ+ВЧ-разряде в 2-3 раза выше, чем в случае использования только импульсного ВЧ-разряда. Наведено результати ВЧ-чистки в стелараторі Ураган-2М з використанням УКХ безперервного розряду в атмосфері гелію. При цьому частина відкачуваного газу конденсувалась на криогенну пастку. Процес чищення контролювався за допомогою вимірювання тиску газу Pг у відсіченому об`ємі з пасткою після її отеплення. Значення Pг пропорційно кількості відкачуваного газу. Виявлено, що кількість сконденсованого на пастці газу при комбінованому УКХ + ВЧ-розряді в 2-3 рази вище, ніж у випадку використання тільки імпульсного ВЧ-розряду.
- Published
- 2015
4. Recent advances in vacum sciences and applications
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Stana-Kleinschek, K., Mozetič, M., Ostrikov, K., Ruzic, D. N., Curreli, D., Cvelbar, U., Vesel, A., Primc, G., Leisch, M., Jousten, K., Malyshev, O. B., Hendricks, J. H., Kövér, L., Tagliaferro, A., Conde, O., Silvestre, A. J., Giapintzakis, John, Buljan, M., Radić, N., Dražić, G., Bernstorff, S., Biederman, H., Kylián, O., Hanuš, J., Miloševič, S., Galtayries, A., Dietrich, P., Unger, W., Lehocky, M., Sedlarik, V., Drmota-Petrič, A., Pireaux, J. J., Rogers, J. W., Anderle, M., and Giapintzakis, John [0000-0002-7277-2662]
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Cell death ,Acoustics and Ultrasonics ,Vacuum ,Innovative techniques ,Cardio-vascular disease ,Nanotechnology ,Diseases ,Historic preservation ,Plasma ,Interfaces (materials) ,Vacuum applications ,Tissue engineering ,vacuum science ,Pressure measurement ,Carbon nanomaterials ,Conservation technologies ,Chemistry ,Solid surface ,Solid-liquid interfaces ,Optical interferometer ,Interface ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Surfaces ,Carbon nano-materials ,Surface ,Vacuum technology ,Nanoscience ,Plasmas ,Drug delivery ,Thin-film characterization ,Cultural heritage objects ,Plasma medicine - Abstract
Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid-liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented. © 2014 IOP Publishing Ltd. 47
- Published
- 2014
5. Plasma and Sol-Gel Technology for Creating Nanostructured Surfaces of Fibrous Polymers
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Gorjanc, M., Vasiljević, J., Vesel, Al., Mozetič, M., and Simončič, B.
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modification ,surface activation ,nanostructure ,XPS ,poly(ethylene terephthalate) ,sol-gel ,AFM ,ablation ,plasma ,cellulose - Abstract
For a modification of natural and synthetic fibrous polymers low-pressure ICRF plasma and liquid repellent sol-gel fluoroalkyl-functional siloxane precursor were used. Plasma induced surface chemical and morphological changes on fluorinated poly(ethylene terephthalate) and cellulose were analysed using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Wettability properties of sol-gel functionalized polymers were determined by the goniometric water contact angles and water sliding angle measurements. After plasma treatment the oxygen content on the surface of both polymers increased (increase of O/C ratio) and a nanostructured surface roughness appeared. Plasma ablation caused partially defluorinated nanostructured surface of fluorinated poly(ethylene terephthalate) polymer and increased its hydrophilicity. Plasma activation and etching of cellulose polymer contributed to the creation of highly adhesive and wash resistant sol-gel coating with superhydrophobic, oleophobic and self-cleaning properties. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35391
- Published
- 2012
6. Formation of tetragonal or monoclinic ZrO2coatings by oxygen plasma treatment of Zr74.7Cu19.7Nb5.6glassy thin films
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Panagiotopoulos, N. T., primary, Kovač, J., additional, Mozetič, M., additional, Patsalas, P., additional, and Evangelakis, G. A., additional
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- 2011
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7. Modeling of Electron Kinetics in BF3
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Nikitović, Ž., primary, Šašić, O., additional, Raspopović, Z., additional, Stojanović, V., additional, Radovanov, S., additional, Mozetič, M., additional, and Cvelbar, U., additional
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- 2010
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8. Plazemsko čiščenje kovinskih površin
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Brecelj, F., Drobnič, M., Kveder, M., and Mozetič, M.
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- 1993
9. Antibacterial treatment of LDPE with halogen derivatives via cold plasma.
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Popelka, A., Novák, I., Lehocký, M., Bílek, F., Kleinová, A., Mozetič, M., Špírková, M., and Chodák, I.
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LOW density polyethylene ,BACTERIAL growth ,HALOGENS ,LOW temperature plasmas ,ANTIBACTERIAL agents ,MICROBIAL sensitivity tests ,POLYACRYLIC acid - Abstract
The factor limiting the application of low-density polyethylene (LDPE) in healthcare is its high susceptibility to bacterial growth. For this reason, we here investigated antibacterial treatments of LDPE foils using appropriate antibacterial agents. Benzalkonium chloride and bronopol were selected because of their satisfactory antibacterial effect, which has been confirmed by their application in the medical and cosmetic industries. The aforementioned substances were immobilized by a multistep approach via the grafting of polyacrylic acid (PAA) brushes onto LDPE surfaces pre-treated with low-temperature plasma. Measurements of the surface energy, peel strength of the adhesive joints, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), and atomic force micro scopy (AFM) were used to investigate the surface and adhesive properties of the antibacterial-treated LDPE. Moreover, the antibacterial effect was determined via measurements of the inhibition zone of the Staphylococcus aureus (S. aureus) bacterial strain. The antibacterial activity of benzalkonium chloride was observed to be more pronounced than that of bronopol. Inhibition- zone measurements of Escherichia coli (E. coli) were also conducted, but an antibacterial effect was not observed. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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10. Modeling of Electron Kinetics in BF3.
- Author
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Nikitovic, Ž., Šašić, O., Raspopović, Z., Stojanović, V., Radovanov, S., Mozetič, M., and Cvelbar, U.
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ELECTRON scattering ,DYNAMICS ,NUCLEAR cross sections ,MONTE Carlo method ,ELECTRIC fields ,ELECTRON bombardment conductivity ,DIFFUSION ,PLASMA devices ,ION bombardment - Abstract
In this paper we used the available data for the electron impact scattering cross sections BF
3 to calculate the transport coefficients for electrons. Monte Carlo simulation was used to perform calculations of the transport coefficients as well as the rate coefficients in DC electric fields, crossed electric and magnetic DC and RF fields. [ABSTRACT FROM AUTHOR]- Published
- 2010
11. Plasma-wall interaction studies within the EUROfusion consortium
- Author
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Brezinsek, S., Coenen, J. W., Schwarz-Selinger, T., Schmid, K., Kirschner, A., Hakola, A., Tabares, F. L., Meiden, H. J., Mayoral, M. L., Reinhart, M., Tsitrone, E., Ahlgren, T., Aints, M., Airila, M., Almaviva, S., Alves, E., Angot, T., Anita, V., Arredondo Parra, R., Aumayr, F., Balden, M., Bauer, J., Ben Yaala, M., Berger, B. M., Bisson, R., Björkas, C., Bogdanovic Radovic, I., Borodin, D., Bucalossi, J., Butikova, J., Butoi, B., Čadež, I., Caniello, R., Caneve, L., Cartry, G., Catarino, N., Čekada, M., Ciraolo, G., Ciupinski, L., Colao, F., Corre, Y., Costin, C., Craciunescu, T., Cremona, A., Angeli, M., Castro, A., Dejarnac, R., Dellasega, D., Dinca, P., Dittmar, T., Dobrea, C., Hansen, P., Drenik, A., Eich, T., Elgeti, S., Falie, D., Fedorczak, N., Ferro, Y., Fornal, T., Fortuna-Zalesna, E., Gao, L., Gasior, P., Gherendi, M., Ghezzi, F., Gosar, Greuner, H., Grigore, E., Grisolia, C., Groth, M., Gruca, M., Grzonka, J., Gunn, J. P., Hassouni, K., Heinola, K., Höschen, T., Huber, S., Jacob, W., Jepu, I., Jiang, X., Jogi, I., Kaiser, A., Karhunen, J., Kelemen, M., Köppen, M., Koslowski, H. R., Kreter, A., Kubkowska, M., Laan, M., Laguardia, L., Lahtinen, A., Lasa, A., Lazic, V., Lemahieu, N., Likonen, J., Linke, J., Litnovsky, A., Linsmeier, Ch, Loewenhoff, T., Lungu, C., Lungu, M., Maddaluno, G., Maier, H., Makkonen, T., Manhard, A., Marandet, Y., Markelj, S., Marot, L., Martin Oberkofler, Martin-Rojo, A. B., Martynova, Y., Mateus, R., Matveev, D., Mayer, M., Meisl, G., Mellet, N., Michau, A., Miettunen, J., Möller, S., Morgan, T. W., Mougenot, J., Mozetič, M., Nemanič, V., Neu, R., Nordlund, K., Oberkofler, M., Oyarzabal, E., Panjan, M., Pardanaud, C., Paris, P., Passoni, M., Pegourie, B., Pelicon, P., Petersson, P., Piip, K., Pintsuk, G., Pompilian, G. O., Popa, G., Porosnicu, C., Primc, G., Probst, M., Räisänen, J., Rasinski, M., Ratynskaia, S., Reiser, D., Ricci, D., Richou, M., Riesch, J., Riva, G., Rosinski, M., Roubin, P., Rubel, M., Ruset, C., Safi, E., Sergienko, G., Siketic, Z., Sima, A., Spilker, B., Stadlmayr, R., Steudel, I., Ström, P., Tadic, T., Tafalla, D., Tale, I., Terentyev, D., Terra, A., Tiron, V., Tiseanu, I., Tolias, P., Tskhakaya, D., Uccello, A., Unterberg, B., Uytdenhoven, I., Vassallo, E., Vavpetič, P., Veis, P., Velicu, I. L., Vernimmen, J. W. M., Voitkans, A., Toussaint, U., Weckmann, A., Wirtz, M., Založnik, A., Zaplotnik, R., Jülich Research Centre, Max Planck Institute for Plasma Physics, VTT Technical Research Centre of Finland, CIEMAT, Dutch Institute for Fundamental Energy Research, Culham Science Centre, CEA, University of Helsinki, University of Tartu, Agenzia nazionale per le nuove tecnologie, l'energia e lo sviluppo economico sostenibile, Instituto Superior Tecnico Lisboa, CNRS, Al. I. Cuza University, Vienna University of Technology, Swiss Federal Institute of Technology Lausanne, Ruder Boskovic Institute, University of Latvia, National Institute for Laser, Plasma and Radiation Physics, J. Stefan Institute, National Research Council of Italy, Warsaw University of Technology, Czech Academy of Sciences, Polytechnic University of Milan, Soltan Institute for Nuclear Studies, Department of Applied Physics, University of Innsbruck, KTH Royal Institute of Technology, Belgian Nuclear Research Centre, Comenius University in Bratislava, Aalto-yliopisto, and Aalto University
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power exhaust ,tungsten ,particle exhaust ,plasma-facing components ,beryllium ,plasma-surface interaction - Abstract
The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma-material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.
12. Preparation of thin coatings of titanium compounds with ion implantation
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Mozetič, M., Zalar, A., Jagielski, J., Evangelakis, G. A., Drobnič, M., and Vladimir Chab
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semiconductor compounds ,aes ,srim ibm software ,ion beams ,titanium nitrides ,surface technologies ,surface coatings ,auger electron spectroscopy ,thin films ,stopping and range of ions in matter ,microelectronics ,aes depth profiling ,surface engineering ,ion implantation ,computer simulations ,ti compounds ,ti nitrides ,thin coatings ,ti oxides ,irradiation damages ,titanium compounds ,titanium oxides - Abstract
The growth of thin coatings of titanium oxide and nitride during ion implantation of respective ions into titanium substrate was studied theoretically and experimentally. The IBM SRIM software was used to determine the concentration profiles of implanted ions. the sputtering rate, probability of back - scattering and ion energy loss mechanisms. Theoretical results were compared with experiments. Samples of pure titanium plates were carefully polished and exposed to a flux of oxygen and nitrogen ions with the kinetic energy of 100 keV per molecule (50 keV per atom). The ion doses were 5X10(16), 1X10(17), 2.5X10(17), 5X10(17), 5X10(17), 1X10(18) atoms/cm(2). Depth profiles of the samples were determined by the AES method. Both the theory and experiment showed that the ion range at the low dose was about 90 nm for the case of nitrogen, and 80 nm for the case of oxygen, with depth distribution typical for ion implantation. Experimental results showed that a layer of titanium compound with a constant composition was formed at the ion dose above 7.5X10(17) atoms/cm(2). Informacije Midem-Journal of Microelectronics Electronic Components and Materials
13. Cell Adhesion On Hydrophobic Polymer Surfaces
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Jaganjac, M., Lidija Milkovic, Cipak, A., Mozetič, M., Recek, N., Žarković, N., and Vesel, A.
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Basic Medical Sciences ,plasma surface modification ,human osteosarcoma cells (HOS) ,biopolymers ,hydrophobic surface ,CF4 plasma - Abstract
Adhesion of human osteosarcoma (HOS) cells on hydrophobic polymer surface was studied. Surface of polymer polystyrene (PS) was made hydrophobic by treatment in plasma created in tetrafluoromethane gas (CF4). The PS samples were exposed for 30 s to CF4 plasma created by RF generator powered at 200 W. This treatment time allowed for optimal polymer surface functionalization with fluorine functional groups. This caused an increase of surface hydrophobicity from initial 85° to about 110° as measured by water contact angle. The HOS cells were deposited on untreated and plasma treated samples and incubated for 1, 2 and 6 days. Both untreated and plasma treated samples were tested for biocompatibility by two different methods: optical micrographs were used to study the cell morphology and MTT test was used to study the cell viability. The results showed better adhesion of cells on plasma treated samples with more hydrophobic surface in comparison to the untreated sample. MTT test revealed about 1.6-times higher activity of cell enzymes after 6-day incubation for plasma treated sample. Optical micrographs have shown that both untreated and fluorine-plasma treated polymer surfaces are not optimal for cell proliferation, since cells need about 2 days to adapt to the surface. After this adaptation time cells start to proliferate on the polymer surface, especially, on that one treated in plasma.
14. Modeling of Electron Kinetics in BF3.
- Author
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Nikitovic, Ž., Šašić, O., Raspopović, Z., Stojanović, V., Radovanov, S., Mozetič, M., and Cvelbar, U.
- Subjects
- *
ELECTRON scattering , *DYNAMICS , *NUCLEAR cross sections , *MONTE Carlo method , *ELECTRIC fields , *ELECTRON bombardment conductivity , *DIFFUSION , *PLASMA devices , *ION bombardment - Abstract
In this paper we used the available data for the electron impact scattering cross sections BF3 to calculate the transport coefficients for electrons. Monte Carlo simulation was used to perform calculations of the transport coefficients as well as the rate coefficients in DC electric fields, crossed electric and magnetic DC and RF fields. [ABSTRACT FROM AUTHOR]
- Published
- 2010
15. Low-pressure inductively coupled oxygen plasma loaded with acetone vapours studied by optical emission spectroscopy
- Author
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Glavan, Nataša, Krstulović, Nikša, Kregar, Zlatko, Milošević, Slobodan, Amon, S, Mozetič, M, and Šorli, I
- Subjects
RF aceton plasma ,optical emission spectroscopy - Abstract
Low-pressure inductively coupled oxygen plasma sustained within a linear glass tube was loaded by acetone vapours and characterized by means of the optical emission spectroscopy. Both spatial and temporal emission measurements were performed. Spectra consist mainly of the CO molecular bands which were used to characterize the plasma conditions. Spectral intensity of CO molecular band was studied versus partial acetone vapour and oxygen pressure.
- Published
- 2008
16. Evolution of the Surface Wettability of Vertically Oriented Multilayer Graphene Sheets Deposited by Plasma Technology.
- Author
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Paul D, Zaplotnik R, Primc G, Vesel A, and Mozetič M
- Abstract
Carbon deposits consisting of vertically oriented multilayer graphene sheets on metallic foils represent an interesting alternative to activated carbon in electrical and electrochemical devices such as super-capacitors because of the superior electrical conductivity of graphene and huge surface-mass ratio. The graphene sheets were deposited on cobalt foils by plasma-enhanced chemical vapor deposition using propane as the carbon precursor. Plasma was sustained by an inductively coupled radiofrequency discharge in the H mode at a power of 500 W and a propane pressure of 17 Pa. The precursor effectively dissociated in plasma conditions and enabled the growth of porous films consisting of multilayer graphene sheets. The deposition rate varied with time and peaked at 100 nm/s. The evolution of surface wettability was determined by the sessile drop method. The untreated substrates were moderately hydrophobic at a water contact angle of about 110°. The contact angle dropped to about 50° after plasma treatment for less than a second and increased monotonously thereafter. The maximal contact angle of 130° appeared at a treatment time of about 30 s. Thereafter, it slowly decreased, with a prolonged deposition time. The evolution of the wettability was explained by surface composition and morphology. A brief treatment with oxygen plasma enabled a super-hydrophilic surface finish of the films consisting of multilayer graphene sheets.
- Published
- 2024
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17. Recent Advances in Corrosion Inhibition of Bonded NdFeB Magnets.
- Author
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Primc G and Mozetič M
- Abstract
Bonded permanent NdFeB magnets are useful in numerous applications, including electric vehicles, and the demand is steadily increasing. A major drawback is corrosion due to inadequate wetting of the magnetic particles by liquid polymers such as polyphenylene sulfide or polyamide. Recently reported methods for corrosion inhibition are summarized, and their applicability is critically evaluated. The phosphorylation of magnetic particles inhibits corrosion but does not enable appropriate properties in harsh environments. The same applies to metallic coatings, which usually contain aluminum and zinc. Advanced epoxy adhesives are a promising solution, although some authors have reported inadequate corrosion resistance. The application of composite coatings seems like an appropriate solution, but the exact mechanisms are yet to be studied.
- Published
- 2024
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18. Kinetics of Surface Wettability of Aromatic Polymers (PET, PS, PEEK, and PPS) upon Treatment with Neutral Oxygen Atoms from Non-Equilibrium Oxygen Plasma.
- Author
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Vesel A, Zaplotnik R, Primc G, and Mozetič M
- Abstract
The wettability of polymers is usually inadequate to ensure the appropriate spreading of polar liquids and thus enable the required adhesion of coatings. A standard ecologically benign method for increasing the polymer wettability is a brief treatment with a non-equilibrium plasma rich in reactive oxygen species and predominantly neutral oxygen atoms in the ground electronic state. The evolution of the surface wettability of selected aromatic polymers was investigated by water droplet contact angles deposited immediately after exposing polymer samples to fluxes of oxygen atoms between 3 × 10
20 and 1 × 1023 m-2 s-1 . The treatment time varied between 0.01 and 1000 s. The wettability evolution versus the O-atom fluence for all aromatic polymers followed similar behavior regardless of the flux of O atoms or the type of polymer. In the range of fluences between approximately 5 × 1020 and 5 × 1023 m-2 , the water contact angle decreased exponentially with increasing fluence and dropped to 1/e of the initial value after receiving the fluence close to 5 × 1022 m-2 .- Published
- 2024
- Full Text
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19. The Impact of Plasma Surface Treatments on the Mechanical Properties and Magnetic Performance of FDM-Printed NdFeB/PA12 Magnets.
- Author
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Damnjanović A, Primc G, Zaplotnik R, Mozetič M, and Kovačević N
- Abstract
This study presents a novel approach for improving the interfacial adhesion between Nd-Fe-B spherical magnetic powders and polyamide 12 (PA12) in polymer-bonded magnets using plasma treatments. By applying radio frequency plasma to the magnetic powder and low-pressure microwave plasma to PA12, we achieved a notable enhancement in the mechanical and environmental stability of fused deposition modeling (FDM)-printed Nd-Fe-B/PA12 magnets. The densities of the FDM-printed materials ranged from 92% to 94% of their theoretical values, with magnetic remanence (B
r ) ranging from 85% to 89% of the theoretical values across all batches. The dual plasma-treated batch demonstrated an optimal mechanical profile with an elastic modulus of 578 MPa and the highest ductility at 21%, along with a tensile strength range of 6 to 7 MPa across all batches. Flexural testing indicated that this batch also achieved the highest flexural strength of 15 MPa with a strain of 5%. Environmental stability assessments confirmed that applied plasma treatments did not compromise resistance to corrosion, evidenced by negligible flux loss in both hygrothermal and bulk corrosion tests. These results highlight plasma treatment's potential to enhance mechanical strength, magnetic performance, and environmental stability.- Published
- 2024
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- View/download PDF
20. Surface Modification of Polymers by Plasma Treatment for Appropriate Adhesion of Coatings.
- Author
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Primc G and Mozetič M
- Abstract
In this study, recent advances in tailoring the surface properties of polymers for the optimization of the adhesion of various coatings by non-equilibrium gaseous plasma are reviewed, and important findings are stressed. Different authors have used various experimental setups and reported results that scatter significantly and are sometimes contradictory. The correlations between the processing parameters and the adhesion are drawn, and discrepancies are explained. Many authors have explained improved adhesion with the adjustment of the surface free energy or wettability of the polymer substrate and the surface tension of liquids used for the deposition of thin films. The adhesion force between the polymer substrate and the coating does not always follow the evolution of the surface wettability, which is explained by several effects, including the aging effects due to the hydrophobic recovery and the formation of an interlayer rich in loosely bonded low molecular weight fragments.
- Published
- 2024
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21. Recent Progress in Cellulose Hydrophobization by Gaseous Plasma Treatments.
- Author
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Primc G, Vesel A, Zaplotnik R, Gorjanc M, Gselman P, Lehocký M, and Mozetič M
- Abstract
Cellulose is an abundant natural polymer and is thus promising for enforcing biobased plastics. A broader application of cellulose fibers as a filler in polymer composites is limited because of their hydrophilicity and hygroscopicity. The recent scientific literature on plasma methods for the hydrophobization of cellulose materials is reviewed and critically evaluated. All authors focused on the application of plasmas sustained in fluorine or silicon-containing gases, particularly tetrafluoromethane, and hexamethyldisiloxane. The cellulose materials should be pre-treated with another plasma (typically oxygen) for better adhesion of the silicon-containing hydrophobic coating. In contrast, deposition of fluorine-containing coatings does not require pre-treatment, which is explained by mild etching of the cellulose upon treatment with F atoms and ions. The discrepancy between the results reported by different authors is explained by details in the gas phase and surface kinetics, including the heating of samples due to exothermic surface reactions, desorption of water vapor, competition between etching and deposition, the influence of plasma radiation, and formation of dusty plasma. Scientific and technological challenges are highlighted, and the directions for further research are provided.
- Published
- 2024
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22. Carboxymethylated and Sulfated Furcellaran from Furcellaria lumbricalis and Its Immobilization on PLA Scaffolds.
- Author
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Štěpánková K, Ozaltin K, Sáha P, Vargun E, Domincová-Bergerová E, Vesel A, Mozetič M, and Lehocký M
- Abstract
This study involved the creation of highly porous PLA scaffolds through the porogen/leaching method, utilizing polyethylene glycol as a porogen with a 75% mass ratio. The outcome achieved a highly interconnected porous structure with a thickness of 25 μm. To activate the scaffold's surface and improve its hydrophilicity, radiofrequency (RF) air plasma treatment was employed. Subsequently, furcellaran subjected to sulfation or carboxymethylation was deposited onto the RF plasma treated surfaces with the intention of improving bioactivity. Surface roughness and water wettability experienced enhancement following the surface modification. The incorporation of sulfate/carboxymethyl group (DS = 0.8; 0.3, respectively) is confirmed by elemental analysis and FT-IR. Successful functionalization of PLA scaffolds was validated by SEM and XPS analysis, showing changes in topography and increases in characteristic elements (N, S, Na) for sulfated (SF) and carboxymethylated (CMF). Cytocompatibility was evaluated by using mouse embryonic fibroblast cells (NIH/3T3).
- Published
- 2024
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23. The Influence of Reaction Conditions on the Properties of Graphene Oxide.
- Author
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Huskić M, Kepić D, Kleut D, Mozetič M, Vesel A, Anžlovar A, Bogdanović DB, and Jovanović S
- Abstract
The present study focuses on correlations between three parameters: (1) graphite particle size, (2) the ratio of graphite to oxidizing agent (KMnO
4 ), and (3) the ratio of graphite to acid (H2 SO4 and H3 PO4 ), with the reaction yield, structure, and properties of graphene oxide (GO). The correlations are a challenge, as these three parameters can hardly be separated from each other due to the variations in the viscosity of the system. The larger the graphite particles, the higher the viscosity of GO. Decreasing the ratio of graphite to KMnO4 from 1:4 to 1:6 generally leads to a higher degree of oxidation and a higher reaction yield. However, the differences are very small. Increasing the graphite-to-acid-volume ratio from 1 g/60 mL to 1 g/80 mL, except for the smallest particles, reduced the degree of oxidation and slightly reduced the reaction yield. However, the reaction yield mainly depends on the extent of purification of GO by water, not on the reaction conditions. The large differences in the thermal decomposition of GO are mainly due to the bulk particle size and less to other parameters.- Published
- 2024
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24. Aging of Plasma-Activated Polyethylene and Hydrophobic Recovery of Polyethylene Polymers.
- Author
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Mozetič M
- Abstract
Available literature on the aging of plasma-activated polyethylene due to hydrophobic recovery has been reviewed and critically assessed. A common method for the evaluation of hydrophobic recovery is the determination of the static water contact angle, while the surface free energy does not reveal significant correlations. Surface-sensitive methods for the characterization of chemical composition and structure have limited applicability in studying the aging phenomenon. Aging is driven by thermodynamics, so it is observed even upon storage in a vacuum, and hydrophobic recovery increases with increasing temperature. Storage of plasma-activated polyethylene in the air at ambient conditions follows almost logarithmic behavior during the period studied by most authors; i.e., up to one month. The influence of the storage medium is somehow controversial because some authors reported aging suppression by storing in polar liquids, but others reported the loss of hydrophilicity even after a brief immersion into distilled water. Methods for suppressing aging by hydrophobic recovery include plasma treatment at elevated temperature followed by brief treatment at room temperature and application of energetic ions and photons in the vacuum ultraviolet range. Storing at low temperatures is a trivial alternative, but not very practical. The aging of plasma-activated polyethylene suppresses the adhesion of many coatings, but the correlation between the surface free energy and the adhesion force has yet to be addressed adequately.
- Published
- 2023
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25. Cold plasma within a stable supercavitation bubble - A breakthrough technology for efficient inactivation of viruses in water.
- Author
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Filipić A, Dobnik D, Gutiérrez-Aguirre I, Ravnikar M, Košir T, Baebler Š, Štern A, Žegura B, Petkovšek M, Dular M, Mozetič M, Zaplotnik R, and Primc G
- Subjects
- Animals, Humans, Water, Virus Inactivation, Plasma Gases pharmacology, Viruses
- Abstract
Water scarcity, one of the most pressing challenges we face today, has developed for many reasons, including the increasing number of waterborne pollutants that affect the safety of the water environment. Waterborne human, animal and plant viruses represent huge health, environmental, and financial burden and thus it is important to efficiently inactivate them. Therefore, the main objective of this study was to construct a unique device combining plasma with supercavitation and to evaluate its efficiency for water decontamination with the emphasis on inactivation of viruses. High inactivation (>5 log
10 PFU/mL) of bacteriophage MS2, a human enteric virus surrogate, was achieved after treatment of 0.43 L of recirculating water for up to 4 min. The key factors in the inactivation were short-lived reactive plasma species that damaged viral RNA. Water treated with plasma for a short time required for successful virus inactivation did not cause cytotoxic effects in the in vitro HepG2 cell model system or adverse effects on potato plant physiology. Therefore, the combined plasma-supercavitation device represents an environmentally-friendly technology that could provide contamination-free and safe water., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)- Published
- 2023
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26. Loss of Oxygen Atoms on Well-Oxidized Cobalt by Heterogeneous Surface Recombination.
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Paul D, Mozetič M, Zaplotnik R, Ekar J, Vesel A, Primc G, and Đonlagić D
- Abstract
Calorimetry is a commonly used method in plasma characterization, but the accuracy of the method is tied to the accuracy of the recombination coefficient, which in turn depends on a number of surface effects. Surface effects also govern the kinetics in advanced methods such as atomic layer oxidation of inorganic materials and functionalization of organic materials. The flux of the reactive oxygen atoms for the controlled oxidation of such materials depends on the recombination coefficient of materials placed into the reaction chamber, which in turn depends on the surface morphology, temperature, and pressure in the processing chamber. The recombination coefficient of a well-oxidized cobalt surface was studied systematically in a range of temperatures from 300 to 800 K and pressures from 40 to 200 Pa. The coefficient increased monotonously with decreasing pressure and increasing temperature. The lowest value was about 0.05, and the highest was about 0.30. These values were measured for cobalt foils previously oxidized with oxygen plasma at the temperature of 1300 K. The oxidation caused a rich morphology with an average roughness as deduced from atomic force images of 0.9 µm. The results were compared with literature data, and the discrepancy between results reported by different authors was explained by taking into account the peculiarities of their experimental conditions.
- Published
- 2023
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27. The Sensitivity of Fungi Colonising Buckwheat Grains to Cold Plasma Is Species Specific.
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Mravlje J, Kobal T, Regvar M, Starič P, Zaplotnik R, Mozetič M, and Vogel-Mikuš K
- Abstract
Fungi are the leading cause of plant diseases worldwide and are responsible for enormous agricultural and industrial losses on a global scale. Cold plasma (CP) is a potential tool for eliminating or inactivating fungal contaminants from biological material such as seeds and grains. This study used a low-pressure radiofrequency CP system with oxygen as the feed gas to test the decontamination efficacy of different genera and species commonly colonising buckwheat grains. Two widely accepted methods for evaluating fungal decontamination after CP treatment of seeds were compared: direct cultivation technique or contamination rate method (%) and indirect cultivation or colony-forming units (CFU) method. For most of the tested fungal taxa, an efficient decrease in contamination levels with increasing CP treatment time was observed. Fusarium graminearum was the most susceptible to CP treatment, while Fusarium fujikuroi seems to be the most resistant. The observed doses of oxygen atoms needed for 1-log reduction range from 10
24 -1025 m-2 . Although there was some minor discrepancy between the results obtained from both tested methods (especially in the case of Fusarium spp.), the trends were similar. The results indicate that the main factors affecting decontamination efficiency are spore shape, size, and colouration.- Published
- 2023
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28. Germination and Growth of Plasma-Treated Maize Seeds Planted in Fields and Exposed to Realistic Environmental Conditions.
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Recek N, Zaplotnik R, Vesel A, Primc G, Gselman P, Mozetič M, and Holc M
- Subjects
- Germination drug effects, Zea mays drug effects, Zea mays growth & development, Seeds drug effects, Seeds growth & development, Plasma Gases pharmacology, Oxygen pharmacology, Insect Control
- Abstract
In this study, we applied an inductively coupled, radio frequency oxygen plasma to maize seeds and investigated its effects on seedling emergence, plant number at tasseling, and crop yield of maize in realistic field conditions. Maize seeds of seven different hybrids were treated over two harvest years. In addition to plasma-treated seeds, a control sample, fungicide-treated seeds, an eco-layer, and a plasma and eco-layer combination, were planted. Seedling emergence, plant number at tasseling (plants/m
2 ), and yield (kg/ha), were recorded. In the first harvest year, results were negatively affected by the presence of an insect pest. In the second harvest year, plant number and yield results were more uniform. In both years, for two and three hybrids, respectively, the highest yield arose from plants from plasma-treated seeds, but the differences were only partially significant. Considering our results, plasma treatment of maize seeds appears to have a positive effect on the yield of the plant.- Published
- 2023
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29. Mechanisms Involved in the Modification of Textiles by Non-Equilibrium Plasma Treatment.
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Primc G, Zaplotnik R, Vesel A, and Mozetič M
- Abstract
Plasma methods are often employed for the desired wettability and soaking properties of polymeric textiles, but the exact mechanisms involved in plasma-textile interactions are yet to be discovered. This review presents the fundamentals of plasma penetration into textiles and illustrates mechanisms that lead to the appropriate surface finish of fibers inside the textile. The crucial relations are provided, and the different concepts of low-pressure and atmospheric-pressure discharges useful for the modification of textile's properties are explained. The atmospheric-pressure plasma sustained in the form of numerous stochastical streamers will penetrate textiles of reasonable porosity, so the reactive species useful for the functionalization of fibers deep inside the textile will be created inside the textile. Low-pressure plasmas sustained at reasonable discharge power will not penetrate into the textile, so the depth of the modified textile is limited by the diffusion of reactive species. Since the charged particles neutralize on the textile surface, the neutral species will functionalize the fibers deep inside the textile when low-pressure plasma is chosen for the treatment of textiles.
- Published
- 2022
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30. Effect of Oxygen Plasma Treatment on Wheat Emergence and Yield in the Field.
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Holc M, Mozetič M, Zaplotnik R, Vesel A, Gselman P, and Recek N
- Abstract
This paper investigates the effects of an inductively coupled, radio frequency oxygen plasma on the plant emergence and crop yield of wheat in field growth conditions. Wheat seeds of eight different cultivars were plasma-treated using conditions selected based on preliminary experiments. Additionally, a control sample, as well as seeds treated with fungicide, an eco-layer, or a plasma + eco-layer combination, were planted in parallel. Four cultivars per harvest year were used. Plant emergence (plants/m
2 ) and yield (kg/ha) were followed. There was little variation among the control and the various treatments regarding plant emergence. Regarding yield, there were statistically significant differences, but no discernible trend was seen when comparing the individual treatments. In the case of several cultivars, plasma-treated seeds performed as well as the control, but there was a significant increase in yield only in the case of cultivar 88.5 R. In several cases, yield of plants for plasma-treated seeds was also lower than the control. Our results demonstrate that the response of wheat yield to plasma treatment, as well as to other seed treatments, differs depending on the wheat cultivar.- Published
- 2022
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31. Nanoporous Stainless Steel Materials for Body Implants-Review of Synthesizing Procedures.
- Author
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Benčina M, Junkar I, Vesel A, Mozetič M, and Iglič A
- Abstract
Despite the inadequate biocompatibility, medical-grade stainless steel materials have been used as body implants for decades. The desired biological response of surfaces to specific applications in the body is a highly challenging task, and usually not all the requirements of a biomaterial can be achieved. In recent years, nanostructured surfaces have shown intriguing results as cell selectivity can be achieved by specific surface nanofeatures. Nanoporous structures can be fabricated by anodic oxidation, which has been widely studied for titanium and its alloys, while no systematic studies are so far available for stainless steel (SS) materials. This paper reviews the current state of the art in the anodisation of SS; correlations between the parameters of anodic oxidation and the surface morphology are drawn. The results reported by various authors are scattered because of a variety of experimental configurations. A linear correlation between the pores' diameter anodisation voltage was deduced, while no correlation with other processing parameters was found obvious. The analyses of available data indicated a lack of systematic experiments, which are recommended to understand the kinetics of pore formation and develop techniques for optimal biocompatibility of stainless steel.
- Published
- 2022
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32. Effect of Saccharides Coating on Antibacterial Potential and Drug Loading and Releasing Capability of Plasma Treated Polylactic Acid Films.
- Author
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Karakurt I, Ozaltin K, Pištěková H, Vesela D, Michael-Lindhard J, Humpolícek P, Mozetič M, and Lehocky M
- Subjects
- Anti-Bacterial Agents pharmacology, Carbodiimides pharmacology, Coated Materials, Biocompatible pharmacology, Polyesters pharmacology, Chitosan pharmacology, Staphylococcus aureus
- Abstract
More than half of the hospital-associated infections worldwide are related to the adhesion of bacteria cells to biomedical devices and implants. To prevent these infections, it is crucial to modify biomaterial surfaces to develop the antibacterial property. In this study, chitosan (CS) and chondroitin sulfate (ChS) were chosen as antibacterial coating materials on polylactic acid (PLA) surfaces. Plasma-treated PLA surfaces were coated with CS either direct coating method or the carbodiimide coupling method. As a next step for the combined saccharide coating, CS grafted samples were immersed in ChS solution, which resulted in the polyelectrolyte complex (PEC) formation. Also in this experiment, to test the drug loading and releasing efficiency of the thin film coatings, CS grafted samples were immersed into lomefloxacin-containing ChS solution. The successful modifications were confirmed by elemental composition analysis (XPS), surface topography images (SEM), and hydrophilicity change (contact angle measurements). The carbodiimide coupling resulted in higher CS grafting on the PLA surface. The coatings with the PEC formation between CS-ChS showed improved activity against the bacteria strains than the separate coatings. Moreover, these interactions increased the lomefloxacin amount adhered to the film coatings and extended the drug release profile. Finally, the zone of inhibition test confirmed that the CS-ChS coating showed a contact killing mechanism while drug-loaded films have a dual killing mechanism, which includes contact, and release killing.
- Published
- 2022
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33. The Influence of Glow and Afterglow Cold Plasma Treatment on Biochemistry, Morphology, and Physiology of Wheat Seeds.
- Author
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Starič P, Mravlje J, Mozetič M, Zaplotnik R, Šetina Batič B, Junkar I, and Vogel Mikuš K
- Subjects
- Germination, Seedlings, Seeds, alpha-Amylases, Plasma Gases pharmacology, Triticum physiology
- Abstract
Cold plasma (CP) technology is a technique used to change chemical and morphological characteristics of the surface of various materials. It is a newly emerging technology in agriculture used for seed treatment with the potential of improving seed germination and yield of crops. Wheat seeds were treated with glow (direct) or afterglow (indirect) low-pressure radio-frequency oxygen plasma. Chemical characteristics of the seed surface were evaluated by XPS and FTIR analysis, changes in the morphology of the seed pericarp were analysed by SEM and AFM, and physiological characteristics of the seedlings were determined by germination tests, growth studies, and the evaluation of α-amylase activity. Changes in seed wettability were also studied, mainly in correlation with functionalization of the seed surface and oxidation of lipid molecules. Only prolonged direct CP treatment resulted in altered morphology of the seed pericarp and increased its roughness. The degree of functionalization is more evident in direct compared to indirect CP treatment. CP treatment slowed the germination of seedlings, decreased the activity of α-amylase in seeds after imbibition, and affected the root system of seedlings.
- Published
- 2022
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34. Hydrophobic Recovery of Plasma-Hydrophilized Polyethylene Terephthalate Polymers.
- Author
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Primc G and Mozetič M
- Abstract
Oxygen plasma is widely used for enhancing the wettability of numerous polymers, including polyethylene terephthalate (PET). The treatment with plasma containing oxygen will cause surface functionalization with polar functional groups, which will, in turn, improve the wettability. However, the exact mechanisms leading to the hydrophilic or even super-hydrophilic surface finish are still insufficiently explored. The wettability obtained by plasma treatment is not permanent, since the hydrophobic recovery is usually reported. The mechanisms of hydrophobic recovery are reviewed and explained. Methods for suppressing this effect are disclosed and explained. The recommended treatment which assures stable hydrophilicity of PET samples is the treatment with energetic ions and/or vacuum ultraviolet radiation (VUV). The influence of various plasma species on the formation of the highly hydrophilic surface finish and stability of adequate wettability of PET materials is discussed.
- Published
- 2022
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35. Surface Modifications of Wheat Cultivar Bologna upon Treatment with Non-Equilibrium Gaseous Plasma.
- Author
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Holc M, Vesel A, Zaplotnik R, Paul D, Primc G, Mozetič M, Gselman P, and Recek N
- Abstract
Seeds of wheat cultivar Bologna were treated with a low-pressure, inductively coupled, radio frequency oxygen plasma. E-mode and H-mode plasma at the real powers of 25 and 275 W, respectively, was used at treatment times of 0.1-300 s. Plasma affected seed surface chemistry, determined by XPS, and surface topography, visualized by SEM. The combined effects of functionalization and etching modified seed surface wettability. The water contact angle (WCA) exponentially decreased with treatment time and correlated with the product of discharge power and treatment time well. Super-hydrophilicity was seen at a few 1000 Ws, and the necessary condition was over 35 at.% of surface oxygen. Wettability also correlated well with O-atom dose, where super-hydrophilicity was seen at 10
24 -1025 m-2 . A relatively high germination percentage was seen, up to 1000 Ws (O-atom dose 1023 -1024 m-2 ), while seed viability remained unaffected only up to about 100 Ws. Extensively long treatments decreased germination percentage and viability.- Published
- 2022
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36. Decontamination and Germination of Buckwheat Grains upon Treatment with Oxygen Plasma Glow and Afterglow.
- Author
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Mravlje J, Regvar M, Starič P, Zaplotnik R, Mozetič M, and Vogel-Mikuš K
- Abstract
Buckwheat is an alternative crop known for its many beneficial effects on our health. Fungi are an important cause of plant diseases and food spoilage, often posing a threat to humans and animals. This study reports the effects of low-pressure cold plasma treatment on decontamination and germination of common (CB) and Tartary buckwheat (TB) grains. Both plasma glow and afterglow were applied. The glow treatment was more effective in decontamination: initial contamination was reduced to less than 30% in CB and 10% in TB. Fungal diversity was also affected as only a few genera persisted after the glow treatment; however, it also significantly reduced or even ceased the germination capacity of both buckwheat species. Detailed plasma characterisation by optical spectroscopy revealed extensive etching of outer layers as well as cotyledons. Afterglow treatment resulted in a lower reduction of initial fungal contamination (up to 30% in CB and up to 50% in TB) and had less impact on fungal diversity but did not drastically affect germination: 60-75% of grains still germinated even after few minutes of treatment. The vacuum conditions alone did not affect the fungal population or the germination despite an extensive release of water.
- Published
- 2022
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37. Biocompatibility and Mechanical Stability of Nanopatterned Titanium Films on Stainless Steel Vascular Stents.
- Author
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Yelkarasi C, Recek N, Kazmanli K, Kovač J, Mozetič M, Urgen M, and Junkar I
- Subjects
- Coated Materials, Biocompatible pharmacology, Endothelial Cells metabolism, Oxides, Oxygen, Plastics, Stents, Surface Properties, Stainless Steel, Titanium
- Abstract
Nanoporous ceramic coatings such as titania are promoted to produce drug-free cardiovascular stents with a low risk of in-stent restenosis ( ISR ) because of their selectivity towards vascular cell proliferation. The brittle coatings applied on stents are prone to cracking because they are subjected to plastic deformation during implantation. This study aims to overcome this problem by using a unique process without refraining from biocompatibility. Accordingly, a titanium film with 1 µm thickness was deposited on 316 LVM stainless-steel sheets using magnetron sputtering. Then, the samples were anodized to produce nanoporous oxide. The nanoporous oxide was removed by ultrasonication, leaving an approximately 500 nm metallic titanium layer with a nanopatterned surface. XPS studies revealed the presence of a 5 nm-thick TiO
2 surface layer with a trace amount of fluorinated titanium on nanopatterned surfaces. Oxygen plasma treatment of the nanopatterned surface produced an additional 5 nm-thick fluoride-free oxide layer. The samples did not exhibit any cracking or spallation during plastic deformation. Cell viability studies showed that nanopatterned surfaces stimulate endothelial cell proliferation while reducing the proliferation of smooth muscle cells. Plasma treatment further accelerated the proliferation of endothelial cells. Activation of blood platelets did not occur on oxygen plasma-treated, fluoride-free nanopatterned surfaces. The presented surface treatment method can also be applied to other stent materials such as CoCr, nitinol, and orthopedic implants.- Published
- 2022
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38. Comparison of Plasma Deposition of Carbon Nanomaterials Using Various Polymer Materials as a Carbon Atom Source.
- Author
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Vesel A, Zaplotnik R, Primc G, Paul D, and Mozetič M
- Abstract
Carbon nanowalls are promising materials for various electrochemical devices due to their chemical inertness, desirable electrical conductivity, and excellent surface-to-mass ratio. Standard techniques, often based on plasma-assisted deposition using gaseous precursors, enable the synthesis of top-quality carbon nanowalls, but require long deposition times which represents a serious obstacle for mass applications. Here, an alternative deposition technique is presented. The carbon nanowalls were synthesized on titanium substrates using various polymers as solid precursors. A solid precursor and the substrate were mounted into a low-pressure plasma reactor. Plasma was sustained by an inductively coupled radiofrequency discharge in the H-mode at the power of 500 W. Spontaneous growth of carbon nanomaterials was observed for a variety of polymer precursors. The best quality of carbon nanowalls was obtained using aliphatic polyolefins. The highest growth rate of a thin film of carbon nanowalls of about 200 nm/s was observed. The results were explained by different degradation mechanisms of polymers upon plasma treatment and the surface kinetics.
- Published
- 2022
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- View/download PDF
39. Approaches to Inactivating Aflatoxins-A Review and Challenges.
- Author
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Kutasi K, Recek N, Zaplotnik R, Mozetič M, Krajnc M, Gselman P, and Primc G
- Subjects
- Humans, Aflatoxins chemistry, Crops, Agricultural, Decontamination, Food Contamination prevention & control, Plasma Gases chemistry
- Abstract
According to the World Health Organization, the contamination of crops with aflatoxins poses a significant economic burden, estimated to affect 25% of global food crops. In the event that the contaminated food is processed, aflatoxins enter the general food supply and can cause serious diseases. Aflatoxins are distributed unevenly in food or feedstock, making eradicating them both a scientific and a technological challenge. Cooking, freezing, or pressurizing have little effect on aflatoxins. While chemical methods degrade toxins on the surface of contaminated food, the destruction inside entails a slow process. Physical techniques, such as irradiation with ultraviolet photons, pulses of extensive white radiation, and gaseous plasma, are promising; yet, the exact mechanisms concerning how these techniques degrade aflatoxins require further study. Correlations between the efficiency of such degradation and the processing parameters used by various authors are presented in this review. The lack of appropriate guidance while interpreting the observed results is a huge scientific challenge.
- Published
- 2021
- Full Text
- View/download PDF
40. Rapid Functionalization of Polytetrafluorethylene (PTFE) Surfaces with Nitrogen Functional Groups.
- Author
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Vesel A, Zaplotnik R, Primc G, Mozetič M, Katan T, Kargl R, Mohan T, and Kleinschek KS
- Abstract
The biocompatibility of body implants made from polytetrafluoroethylene (PTFE) is inadequate; therefore, the surface should be grafted with biocompatible molecules. Because PTFE is an inert polymer, the adhesion of the biocompatible film may not be appropriate. Therefore, the PFTE surface should be modified to enable better adhesion, preferably by functionalization with amino groups. A two-step process for functionalization of PTFE surface is described. The first step employs inductively coupled hydrogen plasma in the H-mode and the second ammonia plasma. The evolution of functional groups upon treatment with ammonia plasma in different modes is presented. The surface is saturated with nitrogen groups within a second if ammonia plasma is sustained in the H-mode at the pressure of 35 Pa and forward power of 200 W. The nitrogen-rich surface film persists for several seconds, while prolonged treatment causes etching. The etching is suppressed but not eliminated using pulsed ammonia plasma at 35 Pa and 200 W. Ammonia plasma in the E-mode at the same pressure, but forward power of 25 W, causes more gradual functionalization and etching was not observed even at prolonged treatments up to 100 s. Detailed investigation of the XPS spectra enabled revealing the surface kinetics for all three cases.
- Published
- 2021
- Full Text
- View/download PDF
41. Non-Equilibrium Plasma Methods for Tailoring Surface Properties of Polyvinylidene Fluoride: Review and Challenges.
- Author
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Vesel A, Zaplotnik R, Primc G, Mozetič M, Katan T, Kargl R, Mohan T, and Kleinschek KS
- Abstract
Modification and functionalization of polymer surface properties is desired in numerous applications, and a standard technique is a treatment with non-equilibrium gaseous plasma. Fluorinated polymers exhibit specific properties and are regarded as difficult to functionalize with polar functional groups. Plasma methods for functionalization of polyvinylidene fluoride (PVDF) are reviewed and different mechanisms involved in the surface modification are presented and explained by the interaction of various reactive species and far ultraviolet radiation. Most authors used argon plasma but reported various results. The discrepancy between the reported results is explained by peculiarities of the experimental systems and illustrated by three mechanisms. More versatile reaction mechanisms were reported by authors who used oxygen plasma for surface modification of PVDF, while plasma sustained in other gases was rarely used. The results reported by various authors are analyzed, and correlations are drawn where feasible. The processing parameters reported by different authors were the gas pressure and purity, the discharge configuration and power, while the surface finish was predominantly determined by X-ray photoelectron spectroscopy (XPS) and static water contact angle (WCA). A reasonably good correlation was found between the surface wettability as probed by WCA and the oxygen concentration as probed by XPS, but there is hardly any correlation between the discharge parameters and the wettability.
- Published
- 2021
- Full Text
- View/download PDF
42. The Oleofobization of Paper via Plasma Treatment.
- Author
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Resnik M, Levičnik E, Gosar Ž, Zaplotnik R, Kovač J, Ekar J, Mozetič M, and Junkar I
- Abstract
Cellulose is a promising biomass material suitable for high volume applications. Its potential lies in sustainability, which is becoming one of the leading trends in industry. However, there are certain drawbacks of cellulose materials which limit their use, especially their high wettability and low barrier properties, which can be overcome by applying thin coatings. Plasma technologies present a high potential for deposition of thin environmentally friendly and recyclable coatings. In this paper, two different plasma reactors were used for coating two types of cellulose-based substrates with hexamethyldisiloxane (HMDSO). The changes in surface characteristics were measured by atomic force microscopy (AFM), scanning electron microscopy (SEM), surface free energy and contact angles measurements, X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS). Successful oleofobization was observed for an industrial scale reactor where pure HMDSO was used in the absence of oxygen.
- Published
- 2021
- Full Text
- View/download PDF
43. Germination of Phaseolus vulgaris L. Seeds after a Short Treatment with a Powerful RF Plasma.
- Author
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Recek N, Holc M, Vesel A, Zaplotnik R, Gselman P, Mozetič M, and Primc G
- Subjects
- Photoelectron Spectroscopy, Plant Development drug effects, Seeds ultrastructure, Surface Properties, Water, Wettability, Germination drug effects, Phaseolus drug effects, Phaseolus growth & development, Plasma Gases pharmacology, Seeds drug effects, Seeds growth & development
- Abstract
Seeds of common bean ( Phaseolus vulgaris L.), of the Etna variety, were treated with low-pressure oxygen plasma sustained by an inductively coupled radiofrequency discharge in the H-mode for a few seconds. The high-intensity treatment improved seed health in regard to fungal contamination. Additionally, it increased the wettability of the bean seeds by altering surface chemistry, as established by X-ray photoelectron spectroscopy, and increasing surface roughness, as seen with a scanning electron microscope. The water contact angle at the seed surface dropped to immeasurably low values after a second of plasma treatment. Hydrophobic recovery within a month returned those values to no more than half of the original water contact angle, even for beans treated for the shortest time (0.5 s). Increased wettability resulted in accelerated water uptake. The treatment increased the bean radicle length, which is useful for seedling establishment in the field. These findings confirm that even a brief plasma treatment is a useful technique for the disinfection and stimulation of radicle growth. The technique is scalable to large systems due to the short treatment times.
- Published
- 2021
- Full Text
- View/download PDF
44. Recent Advances in the Plasma-Assisted Synthesis of Zinc Oxide Nanoparticles.
- Author
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Primc G, Brenčič K, Mozetič M, and Gorjanc M
- Abstract
An overview of recent work on the low-temperature plasma-assisted synthesis of zinc oxide (ZnO) nanoparticles is presented and interpreted in terms of gas-phase and surface reactions with illustrated examples. The thermodynamical nonequilibrium conditions allow the formation of chemically reactive species with a potential energy of several eV, which readily interact with the Zn precursors and initiate reactions leading to the formation of nanoparticles or nanowires. The high-quality nanowires were synthesized from Zn powders only upon interaction with moderately ionized plasma in a narrow range of plasma parameters. This technique is promising for the synthesis of large quantities of nanowires with aspect ratios well above 10, but the exact range of parameters remains to be determined. Apart from the ex situ techniques, the ZnO nanoparticles can be synthesized by depositing a film of precursors (often Zn salts or Zn-containing organometallic compounds) and exposing them to oxygen plasma. This technique is useful for the synthesis of well-adherent ZnO nanoparticles on heat-sensitive objects but requires further scientific validation as it often leads to the formation of a semicontinuous ZnO film rather than nanoparticles. Both low-pressure and atmospheric plasmas are useful in converting the precursor film into ZnO nanoparticles despite completely different mechanisms.
- Published
- 2021
- Full Text
- View/download PDF
45. Cold Plasma Affects Germination and Fungal Community Structure of Buckwheat Seeds.
- Author
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Mravlje J, Regvar M, Starič P, Mozetič M, and Vogel-Mikuš K
- Abstract
Crop seeds are frequently colonised by fungi from the field or storage places. Some fungi can cause plant diseases or produce mycotoxins, compromising the use of seeds as seeding material, food or feed. We have investigated the effects of cold plasma (CP) on seed germination and diversity of seed-borne fungi in common and Tartary buckwheat. The seeds were treated with CP for 15, 30, 45, 60, 90, and 120 s in a low-pressure radiofrequency system using oxygen as the feed gas. The fungi from the seed surface and fungal endophytes were isolated using potato dextrose agar plates. After identification by molecular methods, the frequency and diversity of fungal strains were compared between CP treated and chemically surface-sterilised (30% of H
2 O2 ) seeds. CP treatments above 60 s negatively affected the germination of both buckwheat species. A significant reduction in fungal frequency and diversity was observed after 90 s and 120 s in common and Tartary buckwheat, respectively. The filamentous fungi of genera Alternaria and Epicoccum proved to be the most resistant to CP. The results of our study indicate that CP treatment used in our study may be applicable in postharvest and food production, but not for further seed sowing.- Published
- 2021
- Full Text
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46. One-Step Plasma Synthesis of Nitrogen-Doped Carbon Nanomesh.
- Author
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Vesel A, Zaplotnik R, Primc G, Pirker L, and Mozetič M
- Abstract
A one-step method for plasma synthesis of nitrogen-doped carbon nanomesh is presented. The method involves a molten polymer, which is a source of carbon, and inductively coupled nitrogen plasma, which is a source of highly reactive nitrogen species. The method enables the deposition of the nanocarbon layer at a rate of almost 0.1 µm/s. The deposited nanocarbon is in the form of randomly oriented multilayer graphene nanosheets or nanoflakes with a thickness of several nm and an area of the order of 1000 nm
2 . The concentration of chemically bonded nitrogen on the surface of the film increases with deposition time and saturates at approximately 15 at.%. Initially, the oxygen concentration is up to approximately 10 at.% but decreases with treatment time and finally saturates at approximately 2 at.%. Nitrogen is bonded in various configurations, including graphitic, pyridinic, and pyrrolic nitrogen.- Published
- 2021
- Full Text
- View/download PDF
47. Sterilization of polypropylene membranes of facepiece respirators by ionizing radiation.
- Author
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Pirker L, Krajnc AP, Malec J, Radulović V, Gradišek A, Jelen A, Remškar M, Mekjavić IB, Kovač J, Mozetič M, and Snoj L
- Abstract
Ionizing radiation has been identified as an option for sterilization of disposable filtering facepiece respirators in situations where the production of the respirators cannot keep up with demand. Gamma radiation and high energy electrons penetrate deeply into the material and can be used to sterilize large batches of masks within a short time period. In relation to reports that sterilization by ionizing radiation reduces filtration efficiency of polypropylene membrane filters on account of static charge loss, we have demonstrated that both gamma and electron beam irradiation can be used for sterilization, provided that the respirators are recharged afterwards., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 The Authors.)
- Published
- 2021
- Full Text
- View/download PDF
48. Inactivation of Pepper Mild Mottle Virus in Water by Cold Atmospheric Plasma.
- Author
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Filipić A, Dobnik D, Tušek Žnidarič M, Žegura B, Štern A, Primc G, Mozetič M, Ravnikar M, Žel J, and Gutierrez Aguirre I
- Abstract
Water scarcity is one of the greatest threats for human survival and quality of life, and this is increasingly contributing to the risk of human, animal and plant infections due to waterborne viruses. Viruses are transmitted through polluted water, where they can survive and cause infections even at low concentrations. Plant viruses from the genus Tobamovirus are highly mechanically transmissible, and cause considerable damage to important crops, such as tomato. The release of infective tobamoviruses into environmental waters has been reported, with the consequent risk for arid regions, where these waters are used for irrigation. Virus inactivation in water is thus very important and cold atmospheric plasma (CAP) is emerging in this field as an efficient, safe, and sustainable alternative to classic waterborne virus inactivation methods. In the present study we evaluated CAP-mediated inactivation of pepper mild mottle virus (PMMoV) in water samples. PMMoV is a very resilient water-transmissible tobamovirus that can survive transit through the human digestive tract. The efficiency of PMMoV inactivation was characterized for infectivity and virion integrity, and at the genome level, using test plant infectivity assays, transmission electron microscopy, and molecular methods, respectively. Additionally, the safety of CAP treatment was determined by testing the cytotoxic and genotoxic properties of CAP-treated water on the HepG2 cell line. 5-min treatment with CAP was sufficient to inactivate PMMoV without introducing any cytotoxic or genotoxic effects in the in-vitro cell model system. These data on inactivation of such stable waterborne virus, PMMoV, will encourage further examination of CAP as an alternative for treatment of potable and irrigation waters, and even for other water sources, with emphasis on inactivation of various viruses including enteric viruses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Filipić, Dobnik, Tušek Žnidarič, Žegura, Štern, Primc, Mozetič, Ravnikar, Žel and Gutierrez Aguirre.)
- Published
- 2021
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49. Modulation of Differentiation of Embryonic Stem Cells by Polypyrrole: The Impact on Neurogenesis.
- Author
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Skopalová K, Radaszkiewicz KA, Kašpárková V, Stejskal J, Bober P, Junkar I, Mozetič M, Capáková Z, Lehocký M, Kašparová M, Pacherník J, and Humpolíček P
- Subjects
- Animals, Basic Helix-Loop-Helix Transcription Factors genetics, Cell Differentiation genetics, Cell Line, Embryoid Bodies cytology, Gene Expression drug effects, Mice, Molecular Structure, Mouse Embryonic Stem Cells cytology, Mouse Embryonic Stem Cells metabolism, Neural Stem Cells cytology, Neural Stem Cells drug effects, Neural Stem Cells metabolism, Neurogenesis genetics, PAX6 Transcription Factor genetics, Polymers chemistry, Pyrroles chemistry, Reverse Transcriptase Polymerase Chain Reaction, SOXB1 Transcription Factors genetics, Cell Differentiation drug effects, Embryoid Bodies drug effects, Mouse Embryonic Stem Cells drug effects, Neurogenesis drug effects, Polymers pharmacology, Pyrroles pharmacology
- Abstract
The active role of biomaterials in the regeneration of tissues and their ability to modulate the behavior of stem cells in terms of their differentiation is highly advantageous. Here, polypyrrole, as a representantive of electro-conducting materials, is found to modulate the behavior of embryonic stem cells. Concretely, the aqueous extracts of polypyrrole induce neurogenesis within embryonic bodies formed from embryonic stem cells. This finding ledto an effort to determine the physiological cascade which is responsible for this effect. The polypyrrole modulates signaling pathways of Akt and ERK kinase through their phosphorylation. These effects are related to the presence of low-molecular-weight compounds present in aqueous polypyrrole extracts, determined by mass spectroscopy. The results show that consequences related to the modulation of stem cell differentiation must also be taken into account when polypyrrole is considered as a biomaterial.
- Published
- 2021
- Full Text
- View/download PDF
50. Effects of Nonthermal Plasma on Morphology, Genetics and Physiology of Seeds: A Review.
- Author
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Starič P, Vogel-Mikuš K, Mozetič M, and Junkar I
- Abstract
Nonthermal plasma (NTP), or cold plasma, has shown many advantages in the agriculture sector as it enables removal of pesticides and contaminants from the seed surface, increases shelf life of crops, improves germination and resistance to abiotic stress. Recent studies show that plasma treatment indeed offers unique and environmentally friendly processing of different seeds, such as wheat, beans, corn, soybeans, barley, peanuts, rice and Arabidopsis thaliana , which could reduce the use of agricultural chemicals and has a high potential in ecological farming. This review covers the main concepts and underlying principles of plasma treatment techniques and their interaction with seeds. Different plasma generation methods and setups are presented and the influence of plasma treatment on DNA damage, gene expression, enzymatic activity, morphological and chemical changes, germination and resistance to stress, is explained. Important plasma treatment parameters and interactions of plasma species with the seed surface are presented and critically discussed in correlation with recent advances in this field. Although plasma agriculture is a relatively new field of research, and the complex mechanisms of interactions are not fully understood, it holds great promise for the future. This overview aims to present the advantages and limitations of different nonthermal plasma setups and discuss their possible future applications.
- Published
- 2020
- Full Text
- View/download PDF
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