Effect Of Non-thermal Plasma Treatment Research Articles

Effect of non-thermal plasma treatment and resin cements on the bond strength of zirconia ceramics with different yttria concentrations.

To investigate the effect of different surface treatments and resin cements on the shear bond strength of zirconia ceramics with different yttria concentrations. Zirconia blocks characterized by different yttria concentrations [Vita YZ HT (HT), Vita YZ ST (ST) and Vita YZ XT (XT)] were used to prepare disc-shaped specimens (n=252). Specimens prepared to investigate shear bond strength (SBS), water contact angle and surface roughness (Ra) were divided into four subgroups; control (C), sandblasting (S), sandblasting+nonthermal plasma treatment (SNTP) and nonthermal plasma treatment (NTP). For SBS testing, specimens were further divided into two groups (n=108) according to the luting cement used [Panavia F2.0 (P)and Rely X U200 (R)]. The water contact angles were determined by sessile drop technique and Ra was analyzed with optical profilometer. SBS tests were performed in a universal testing machine at a crosshead speed of 0.5 mm/min. The data sets were statistically analyzed with two and three-way ANOVAs followed by post-hoc comparisons (α=0.05). The water contact angle and Ra data were significantly affected by surface treatments. The mean Ra values of ST and XT were significantly lower than HT for the surface treatment groups of C and NTP. The SBS values were significantly different among the groups subjected to different surface treatments. The mean SBS values of surface treatment groups (S, SNTP and NTP) when cemented with R were significantly higher than the groups of C (p<0.05). For the tested zirconia ceramics with different yttria concentrations, non-thermal plasma activation helps to improve SBS and is a promising tool in practical use.

On the Effect of Non-Thermal Atmospheric Pressure Plasma Treatment on the Properties of PET Film.

The aim of the work was to investigate the effect of non-thermal plasma treatment of an ultra-thin polyethylene terephthalate (PET) film on changes in its physicochemical properties and biodegradability. Plasma treatment using a dielectric barrier discharge plasma reactor was carried out in air at room temperature and atmospheric pressure twice for 5 and 15 min, respectively. It has been shown that pre-treatment of the PET surface with non-thermal atmospheric plasma leads to changes in the physicochemical properties of this polymer. After plasma modification, the films showed a more developed surface compared to the control samples, which may be related to the surface etching and oxidation processes. After a 5-min plasma exposure, PET films were characterized by the highest wettability, i.e., the contact angle decreased by more than twice compared to the untreated samples. The differential scanning calorimetry analysis revealed the influence of plasma pretreatment on crystallinity content and the melt crystallization behavior of PET after soil degradation. The main novelty of the work is the fact that the combined action of two factors (i.e., physical and biological) led to a reduction in the content of the crystalline phase in the tested polymeric material.

Initial Effects of Plasma Treatment on Maize Seeds: A Laboratory Study

Planning and modeling seed processing activities necessitate an understanding of the variances and relationships between the physical characteristics of seeds. The goal of this study is to establish the differences in fundamental physical features of selected maize seeds (Ganga Safed-2) and to find connections between these qualities following cold glow discharge plasma treatment. The effects of non-thermal plasma treatment of maize seeds on the rate of the seed’s physical properties like fresh weight, length, and dry weight have been investigated using a radiofrequency glow discharge plasma system. A cylindrical reactor is used for seed treatment. The treatment of maize seeds at 240 seconds and 30 watts has a great impact on their physical properties. We have used various types of gases for plasma treatment such as Nitrogen, Oxygen, Argon, hydrogen, and helium under atmospheric pressure and room temperature.

Mueller polarimetric imaging as a tool for detecting the effect of non-thermal plasma treatment on the skin.

Non-thermal plasma (NTP) is a promising technique studied for several medical applications such as wound healing or tumor reduction. The detection of microstructural variations in the skin is currently performed by histological methods, which are time-consuming and invasive. This study aims to show that full-field Mueller polarimetric imaging is suitable for fast and without-contact detection of skin microstructure modifications induced by plasma treatment. Defrosted pig skin is treated by NTP and analyzed by MPI within 30 minutes. NTP is shown to modify the linear phase retardance and the total depolarization. The tissue modifications are inhomogeneous and present distinct features at the center and the fringes of the plasma-treated area. According to control groups, tissue alterations are primarily caused by the local heating concomitant to plasma-skin interaction.

Effect of Non-Thermal Plasma Treatment on Shear Bond Strength Between Monolithic Zirconia and Resin Cement

Amaç: Bu çalışmanın amacı, farklı plazma tipleri (argon ve oksijen), primer ve kumlama uygulamalarının monolitik zirkonya ile self-adeziv rezin siman arasındaki makaslama bağlanma dayanımına etkisinin incelenmesidir. Gereç ve Yöntemler: Elli adet monolitik zirkonya disk hazırlandı ve sinterlendi. Zirkonya diskler uygulanacak yüzey işlemine göre rastgele beş gruba ayrıldı: Kontrol (herhangi bir yüzey işlemi uygulanmadı), Kumlama (50 μm Al2O3 ile kumlama), Primer (universal seramik primer uygulaması), Oksjen Plazma (10 dakika oksijen plazma uygulaması) ve Argon Plazma (10 dakika argon plazma uygulaması). Örneklere dual-cure bir rezin siman uygulandı ve örneklere 5500 devir termal siklus işlemi yapıldı. Makaslama bağlanma dayanımı testi 1 mm/dak hızında universal bir test cihazında gerçekleştirildi. Veriler tek yönlü ANOVA ve Tukey HSD post-hoc testleri kullanılarak 0.05 anlamlılık düzeyinde analiz edildi. Bulgular: Gruplar arasındaki ortalama makaslama bağlanma dayanımı değerleri arasında istatistiksel olarak anlamlı fark bulundu (P&amp;lt;0.001). Kumlama ve Primer grupları diğer gruplara kıyasla en yüksek bağlanma dayanımı değerlerini gösterdi ancak aralarında fark bulunmadı (P&amp;gt;0.05). Oksijen ve Argon Plazma grupları Kontrol grubuna göre daha yüksek ancak Kumlama ve Primer gruplarına kıyasla daha düşük bağlanma dayanımı değerleri gösterdi (P&amp;lt;0.001). Plazma grupları arasında anlamlı bir fark bulunmadı (P&amp;gt;0.05). Sonuç: Plazma uygulaması rezin ile zirkonya arasındaki bağlantıyı arttırmıştır ancak bu artış kumlama ve primer uygulamaları seviyesinde olmamıştır. Primer ve kumlama uygulamaları birbirine alternatif yöntemler olarak kullanılabilir.

Effect of Non-Thermal Plasma Treatment of Contaminated Zirconia Surface on Porphyromonas gingivalis Adhesion and Osteoblast Viability.

Plasma treatment on a zirconia surface prevents bacterial contamination and maintains osteoblast activity. To assess the degree of adhesion of Porphyromonas gingivalis on a zirconia surface after non-thermal plasma (NTP) treatment, specimens were treated with plasma for 60, 300, and 600 s, after which P. gingivalis was inoculated onto the surface and incubated for 48 h. To assess osteoblast activity after NTP treatment, osteoblasts (MC3T3-E1) were dispensed onto the specimens contaminated with P. gingivalis immediately after NTP for 60 and 120 s, followed by incubation for 48, 72, and 96 h. P. gingivalis was cultured after 60 s of NTP treatment of zirconia. The NTP and control groups showed no significant difference (p = 0.91), but adhesion was significantly increased following NTP treatment for 300 s or longer (300, 600 s groups) (p < 0.05). After NTP treatment of P. gingivalis-contaminated zirconia, osteoblast activity significantly increased at 72 and 96 h (I60 and I120 s group) in the groups treated with plasma (p < 0.017). Application of NTP to dental zirconia implants for 60 s not only inhibits the proliferation of P. gingivalis, which causes peri-implantitis but also increases osseointegration on zirconia surfaces contaminated with P. gingivalis.

Effect of non-thermal plasma using the isolation barrier vacuum reactor (DBD) on seven broccoli cultivars

Seed treatment with a DBD isolation barrier vacuum reactor. Using the drainage of the insulating barrier in the air at atmospheric pressure and room temperature, the effect of non-thermal plasma treatment of seeds on the development rate of seven broccoli cultivars cultivated in Mosul (Al Rashidiya) was investigated. The use of DBD at atmospheric pressure had a significant influence on germination and plant growth of the seven cultivars of broccoli from the seeds used for a period of 0.5, 1, 3, 5, 10, 15 minutes as compared to the control group. In comparison to the control sample, the favorable effect of plasma therapy on seedling growth for the timing (0.5 and 1 minute) had the optimum timing of exposing (broccoli) seeds to plasma from 3, 5, 10, 15 minutes. On the other hand, a negative effect was found after the seeds were exposed to plasma discharge for an extended period of time. The explanation for this might be due to the mechanical effect of the process of exposing seeds to plasma therapy, which resulted in a decrease in plant development and vitality when compared to the time of 0.5 minutes. These findings revealed that the newly constructed cold plasma reactors may considerably increase seed germination and plant development; however, the plasma processing duration for each seed must be tuned.

Effect of nonthermal plasma treatment on surface roughness and bond strength between veneer ceramic and zirconia core

AbstractThis in vitro study evaluated the effect of nonthermal plasma (NTP) treatment on the surface roughness (Ra) of the zirconia and the shear bond strength (SBS) between the veneer ceramic and the zirconia. Ninety zirconia specimens were divided into six groups according to the surface treatments applied: control with no treatment; sandblasting with 50‐μm Al2O3 particles; oxygen plasma treated for 5 min; oxygen plasma treated for 10 min; argon plasma treated for 5 min; and argon plasma treated for 10 min. Ra values were measured using a profilometer. Specimens (n = 12) were then veneered with a nano‐fluorapatite ceramic, and the SBS test was performed. Scanning electron microscopy, atomic force microscopy, and X‐ray diffraction analyses were performed. The sandblasting procedure significantly increased the surface roughness; however, the plasma groups showed similar Ra values compared to the control group. NTP and sandblasting treatment significantly increased the bond strength and led to higher SBS values than the control. Plasma application did not induce phase transformation; however, sandblasting caused monoclinic phase transformation of the zirconia. NTP application (either oxygen or argon) can enhance the bond strength between the veneer ceramic and the zirconia core without altering the surface morphology or causing zirconia phase transformation.

The study of plasma effects on quinine solutions

AbstractThis study compares the effects of nonthermal plasma treatment on quinine water solutions for two configurations—the corona‐like discharge and the gliding arc discharge (GAD). Different electrolytes were added to the quinine solutions to modify the initial pH and enhance electrical conductivity for plasma discharge ignition directly in the liquid. A slightly higher quinine decomposition rate of 2.9 μg W−1 after 5 min of the treatment was achieved by GAD. From measured spectra, it was found that the absorption maximum at 332 nm was split into two separated peaks in the acidic and basic solution. The study of the time stability of quinine solutions has revealed quinine instability and that postpreparation time has influenced the plasma treatment effect.

Effects of Non-Thermal Plasma Treatment on Seed Germination and Early Growth of Leguminous Plants-A Review.

The legumes (Fabaceae family) are the second most important agricultural crop, both in terms of harvested area and total production. They are an important source of vegetable proteins and oils for human consumption. Non-thermal plasma (NTP) treatment is a new and effective method in surface microbial inactivation and seed stimulation useable in the agricultural and food industries. This review summarizes current information about characteristics of legume seeds and adult plants after NTP treatment in relation to the seed germination and seedling initial growth, surface microbial decontamination, seed wettability and metabolic activity in different plant growth stages. The information about 19 plant species in relation to the NTP treatment is summarized. Some important plant species as soybean (Glycine max), bean (Phaseolus vulgaris), mung bean (Vigna radiata), black gram (V. mungo), pea (Pisum sativum), lentil (Lens culinaris), peanut (Arachis hypogaea), alfalfa (Medicago sativa), and chickpea (Cicer aruetinum) are discussed. Likevise, some less common plant species i.g. blue lupine (Lupinus angustifolius), Egyptian clover (Trifolium alexandrinum), fenugreek (Trigonella foenum-graecum), and mimosa (Mimosa pudica, M. caesalpiniafolia) are mentioned too. Possible promising trends in the use of plasma as a seed pre-packaging technique, a reduction in phytotoxic diseases transmitted by seeds and the effect on reducing dormancy of hard seeds are also pointed out.

Effects of Non-thermal Plasma Treatment on the Geopolymerization of Kaolin Clay

Kaolin samples obtained from Cameroon were used to produce geopolymer binders. Prior to its application, the raw kaolin samples were activated through the gliding arc plasma treatment using both spatial post-discharge and direct mode. A mixture of sodium hydroxide and silicate was used as the alkaline solution. In order to study the influence of the modifications generated by the gliding arc plasma treatment on the geopolymerization process, X-ray diffraction, thermogravimetric analysis, differential scanning calorimeter and Fourier transform infrared spectroscopy were carried out. In addition, scanning electron microscopy, nitrogen physisorption and compression tests analysis were also carried out on the resulting geopolymer samples to access their mechanical performance. The results showed that the geopolymerization process was not completed at the curing temperature of 90 °C. Plasma spatial post-discharge mode treated kaolin led to 20.48% increase in compressive strength when compared with the geopolymer prepared from raw kaolin.

Non-Thermal Plasma-A New Green Priming Agent for Plants?

Since the earliest agricultural attempts, humankind has been trying to improve crop quality and yields, as well as protect them from adverse conditions. Strategies to meet these goals include breeding, the use of fertilisers, and the genetic manipulation of crops, but also an interesting phenomenon called priming or adaptive response. Priming is based on an application of mild stress to prime a plant for another, mostly stronger stress. There are many priming techniques, such as osmopriming, halopriming, or using physical agents. Non-thermal plasma (NTP) represents a physical agent that contains a mixture of charged, neutral, and radical (mostly reactive oxygen and nitrogen species) particles, and can cause oxidative stress or even the death of cells or organisms upon interaction. However, under certain conditions, NTP can have the opposite effect, which has been previously documented for many plant species. Seed surface sterilization and growth enhancement are the most-reported positive effects of NTP on plants. Moreover, some studies suggest the role of NTP as a promising priming agent. This review deals with the effects of NTP treatment on plants from interaction with seed and cell surface, influence on cellular molecular processes, up to the adaptive response caused by NTP.

Effects of non-thermal plasma treatment on the polysaccharide from Dendrobium nobile Lindl. And its immune activities in vitro

In order to improve the hydrophilicity and immune activity of the polysaccharide from Dendrobium nobile Lindl., non-thermal plasma was used to treat the polysaccharide. It was found that the hydrophilicity of the polysaccharide plasma-treated was significantly enhanced. Infrared spectra showed that the content of OH in the molecule increased significantly, and the monosaccharide ring changed from β-pyran sugar to β-furan sugar. The detection of SEM, AFM and TEM showed that the degree of cross-linking of surface molecules increased, and the arrangement of the polysaccharide was more compact and orderly. In vitro cell tests showed that the polysaccharide plasma-treated significantly improve the phagocytosis ability of RAW264.7, and promote the secretion of cytokines TNF-α, IL-6, IL-1. However, the cell proliferation test indicated that the polysaccharide did not increase the concentration of cytokines by promoting cell proliferation. RT-PCR showed that the polysaccharide plasma-treated could promote the expression of IL-1β at the transcriptional level. These results showed that non-thermal plasma treatment can effectively enhance the hydrophilicity of the polysaccharide and enhance its immune activity in vitro. Therefore, it can be inferred that the non-thermal plasma technology can be applied to the modification of active polysaccharides and will promote active polysaccharides to work better.

Improvement of growth and yield of soybean plants through the application of non-thermal plasmas to seeds with different health status

Soybean (Glycine max (L.) Merrill) is a globally important crop, providing oil and protein. Diaporthe/Phomopsis complex includes seed-borne pathogens that affect this legume. Non-thermal plasma treatment is a fast, cost-effective and environmental-friendly technology. Soybean seeds were exposed to a quasi-stationary (50 Hz) dielectric barrier discharge plasma operating at atmospheric pressure air. Different carrying gases (O2 and N2) and barrier insulating materials were used. This work was performed to test if the effects of non-thermal plasma treatment applied to healthy and infected seeds persist throughout the entire cycle of plants. To this aim, lipid peroxidation, activity of catalase, superoxide dismutase and guaiacol peroxidase, vegetative growth and agronomic traits were analysed. The results here reported showed that plants grown from infected seeds did not trigger oxidative stress due to the reduction of pathogen incidence in seeds treated with cold plasma. Vegetative growth revealed a similar pattern for plants grown from treated seeds than that found for the healthy control. Infected control, by contrast, showed clear signs of damage. Moreover, plasma treatment itself increased plant growth, promoted a normal and healthy physiological performance and incremented the yield of plants. The implementation of this technology for seeds treatment before sowing could help reducing the use of agrochemicals during the crop cycle.

Evaluation of effects of non-thermal plasma treatment on surface properties of CAD/CAM materials

The purpose of this in vitro study was to evaluate the effect of the non-thermal plasma (NTP) treatment on the wettability and surface roughness of different types of CAD/CAM materials as well as the shear bond strength (SBS) of adhesive resin cement to the treated surfaces. Three different materials, namely; resin nano ceramic, feldspathic ceramic and poly(methyl methacrylate) (PMMA)-based samples were treated with NTP for different time points to evaluate the effect of NTP treatment on the surface properties of CAD/CAM materials. Moreover, surfaces of CAD/CAM materials were visualised with scanning electron microscopy (SEM). A 90-second NTP treatment time was determined as the optimum time for the highest measured wettability, and thus, the 90-second NTP treated samples were used for the SBS test and evaluation of the failure types. Our results revealed the NTP treatment lowered the contact angles and increased the roughness of all tested materials. Moreover, The NTP treatment significantly enhanced the SBS of resin nano ceramic and feldspathic ceramic-based materials. NTP could be considered as a novel pre-treatment method to improve surface properties and the bonding performance of ceramic-based CAD/CAM materials.

Improvement of Biological Properties of Natural Hemostatic Agent by Plasma Technology

The aim of this study was to evaluate the effect of non-thermal plasma treatment on the biological properties of a natural hemostatic agent. The results show that plasma treatment can enhance the biodegradability property of the hemostatic agent by increasing the degradation rate of the specimen up to 94.26% within 7 days. Furthermore, the plasma-treated specimen also exhibited good biocompatibility based on the cell viability test of the fibroblast cells. The cell growth and cell proliferation on this sample were found to be helpful for the wound healing process. With appropriate degradable and biocompatible properties, this modified agent could be beneficial for better control over bleeding during surgery. Research on the physical and mechanical properties are on to develop novel hemostatic products to match the requirements as far as biomedical applications are concerned.

Effects of Nonthermal Plasma Treatment on Decontamination and Sprouting of Radish (Raphanus sativus L.) Seeds

Sprout-related foodborne disease outbreaks are increasingly becoming a concern for food safety. The primary sources of microbial contamination in ready-to-eat sprouts are contaminated seeds, which are improperly disinfected prior to sprouting. In recent years, the application of nonthermal plasmas for seed decontamination is increasingly being investigated as a substitute to regular pre-germination treatments. The present study was intended to evaluate the potentiality of corona discharge plasma jet (CDPJ) for decontaminating microorganisms on radish seeds and to determine the plasma exposure effects on the seed germination as well as physicochemical properties of sprouts grown from the CDPJ-treated seeds. Microbial contaminants, namely, aerobic bacteria, Bacillus cereus, Escherichia coli, Salmonella spp., and molds and yeast were detected in the seeds. All the microorganisms found in the seed samples were reduced in the range of 1.2–2.1 log CFU/g upon treatment using the CDPJ for 3 min. Pseudo-first-order kinetics provides the best fit to the microbial inactivation patterns. The plasma seed treatment for up to 2 min showed beneficial effects on seed germination rate and growth of seedlings. Compared to untreated controls, sprouts grown from the CDPJ-treated seeds exhibited no significant changes in the levels of moisture (mean range 85.45–87.51%), reducing sugars (0.547–0.550%), total phenolic content (6.14–6.29 μg GAL/g), and DPPH radical scavenging activity (78.03–78.60%). Sensory characteristics of radish sprouts grown from the plasma-treated (up to 2 min) seeds were not significantly different from controls. In conclusion, the CDPJ treatment of radish seeds for 2 min not only decreased the seed microbial counts but also led to the improvement of their germination rate and seedling growth, without negatively affecting the physicochemical and sensory properties of their corresponding sprouts.

Improving bond strength of ground and intact enamel to mild self-etch adhesive by plasma treatment

Effects of non-thermal plasma treatment on ground and intact enamel surfaces to improve their bond strength to a mild self-etch adhesive were investigated in this study. Thirty-two bovine incisors were randomly divided into four groups (n=8). Their enamels were subjected to the following preparations: (1) ground and unetched (GU), (2) ground and etched (GE), (3) intact and unetched (IU), and (4) intact and etched (IE). After teeth preparation, each tooth was divided in two portions. One half was treated with a non-thermal plasma brush; the other half was shielded with a blade and used as untreated control. A mild, self-etch adhesive and a dental composite resin were subsequently applied on both surfaces following the manufacturers' instructions. The bond strength of the enamel with the adhesive was evaluated using the micro-tensile bond strength test (μTBS). μTBS results indicate that after plasma treatment, the bond strengths of GU, GE, IU, and IE enamel surfaces to the adhesive significantly increased by 33%, 15%, 35%, and 38% respectively, compared with untreated same tooth control. The mean bond strength of plasma-treated GU and IU enamel substrates to the adhesive were similar to that of untreated GE and IE enamel surfaces (p>0.05). A scanning electron microscope (SEM) was used to examine the fractured surfaces, which shows that more adhesive and composite left on plasma-treated enamel surfaces compared with untreated control. Water and adhesive contact angles measurements indicate that the plasma treatment increased surface energy, which enabled the adhesive to more effectively spread out and cover treated substrates. The Weibull analysis demonstrates that plasma treatment reduced defects in the interfaces and improved GU and IU enamel bond strengths with the adhesive to 41.7MPa and 26.0MPa respectively, which equals the GE and IE enamel bond strengths. This study provides the prospect of replacing the traditional selective etching step using a simple non-thermal plasma treatment technique.

Effect of nonthermal plasma treatment on the surface of dental resins immersed in artificial saliva

Abstract This study aimed (1) to use scanning electron microscopy associated with energy-dispersive spectroscopy (SEM-EDS) to characterize the surface of dental resins after nonthermal plasma (NTP) treatment and (2) to use surface energy analysis to evaluate whether NTP treatment protects the microhardness of the resins against the degradative effects of saliva. Twenty-eight acrylic and composite resin discs were fabricated and divided into four groups. Two groups received no surface treatment [control acrylic resin (Co/AR) and control composite resin (Co/CR] and two groups [NTP-treated acrylic resin (NTP/AR) and NTP-treated composite resin (NTP/CR)] were treated with NTP. One disc from each group was analyzed using SEM-EDS. Ten discs were subjected to surface energy analysis (before and after NTP) and microhardness assessments (at various time points). p&lt;0.05 was used to determine statistical significance. Surface energy decreased after NTP treatment. Microhardness was reduced after 30 days in the Co/AR group and between 15 and 30 days in the NTP/AR group. Microhardness decreased in the Co/CR group after 15 and 30 days, whereas there was no difference after 30 days in the NTP/CR group. SEM images showed the presence of cracks and holes after 30 days in both Co/AR and NTP/AR groups. Cracks and silicon particles were observed after 30 days in the Co/CR group. Both the acrylic and composite resins exhibited hydrophobic properties after NTP treatment. The reduction in microhardness of the acrylic resin after NTP treatment was lower than that of the composite resin.

Effect of nonthermal plasma treatment on surface chemistry of commercially-pure titanium and shear bond strength to autopolymerizing acrylic resin

The effect of nonthermal plasma on the surface characteristics of commercially pure titanium (cp-Ti), and on the shear bond strength between an autopolymerizing acrylic resin and cp-Ti was investigated. A total of 96 discs of cp-Ti were distributed into four groups (n=24): Po (no surface treatment), SB (sandblasting), Po+NTP and SB+NTP (methane plasma). Surface characterization was performed through surface energy, surface roughness, scanning microscopy, energy dispersive spectroscopy, and X-ray diffraction tests. Shear bond strength test was conducted immediately and after thermocycling. Surface treatment affected the surface energy and roughness of cp-Ti discs (P<.001). SEM–EDS showed the presence of the carbide thin film. XRD spectra revealed no crystalline phase changes. The SB+NTP group showed the highest bond strength values (6.76±0.70MPa). Thermocycling reduced the bond strength of the acrylic resin/cp-Ti interface (P<.05), except for Po group. NTP is an effective treatment option for improving the shear bond strength between both materials.