Carbon Dioxide Plasma Research Articles

Platelet-rich plasma versus combined fractional carbon dioxide laser with platelet-rich plasma in the treatment of vitiligo: a comparative study.

PurposeThe aim of this study was to assess the efficacy of platelet-rich plasma (PRP) vs combined fractional CO2 (Fr: CO2) laser with PRP in the treatment of stable nonsegmental vitiligo (NSV) lesions.Patients and methodsThis prospective, randomized, intrapatient, comparative controlled study was conducted between June 2014 and June 2016 at National Institute of Laser Enhanced Sciences (NILES), Cairo University, Cairo, Egypt. Thirty NSV patients were treated with PRP, Fr: CO2 laser, and combined Fr: CO2 laser with PRP. Intrapatient lesions were divide randomly into four groups. Each group was treated by one modality. The fourth group served as a control.Patients received six treatment sessions with 2-week interval for 3 months and were followed up after 3 months.ResultsA highly significant reduction was demonstrated through vitiligo analysis by computer-assisted grid (VACAG) in the combined Fr: CO2 laser with PRP and in the PRP only groups than other groups. These results were confirmed by mean improvement score by physician (MISP) and by VAS with no statistical difference between them. The combined Fr: CO2 laser with PRP group showed minimal side effects. Regardless of the modalities, better improvement was seen in the trunk than the face, extremities, and acral lesions with significant reduction in all regions. Face showed maximum response with combined Fr: CO2 laser with PRP. Trunk showed higher response with PRP. Upper limbs showed highest response with combined Fr: CO2 laser with PRP. Lower limbs showed the highest improvement with Fr: CO2 laser.ConclusionAccording to our study, combined Fr: CO2 laser with PRP achieved superior repigmentation than intradermal (ID) PRP. However, Fr: CO2 alone showed poor improvement. Combined ablative Fr: CO2 laser and PRP therapy followed by sun exposure could be used effectively and safely to treat refractory NSV.

Investigation of amplifying and electrical properties of plasma carbon dioxide lasers

In this work devices to study the electrical and amplifying properties of the plasma of gas mixtures corresponding to carbon dioxide lasers were designs. The devices to a vacuum system that allows them to be pumped out and filled with a working gas mixture are connected. Experiments to study the current-voltage characteristics of the discharge at various pressures of the gas mixture and the diameters of the discharge gaps were carried. The discharge voltage decreases with increasing discharge current, which is characteristic of a discharge with a longitudinal positive column. Large number of experiments to study the enhancement of the emission of carbon dioxide laser in the discharge of various gas mixture were carried: CO2, CO2 : N2, CO2 : N2 : He. The obtained dependences have a maximum at a certain pressure. The three-component mixture has the greatest amplification. The results of the studies were used when replacing the active gas mixture of a carbon dioxide laser, as well as in the educational process when studying the amplifying properties of plasma.

Application of High Pressure with Homogenization, Temperature, Carbon Dioxide, and Cold Plasma for the Inactivation of Bacterial Spores: A Review.

Formation of highly resistant spores is a concern for the safety of low-acid foods as they are a perfect vehicle for food spoilage and/or human infection. For spore inactivation, the strategy usually applied in the food industry is the intensification of traditional preservation methods to sterilization levels, which is often accompanied by decreases of nutritional and sensory properties. In order to overcome these unwanted side effects in food products, novel and emerging sterilization technologies are being developed, such as pressure-assisted thermal sterilization, high-pressure carbon dioxide, high-pressure homogenization, and cold plasma. In this review, the application of these emergent technologies is discussed, in order to understand the effects on bacterial spores and their inactivation and thus ensure food safety of low-acid foods. In general, the application of these novel technologies for inactivating spores is showing promising results. However, it is important to note that each technique has specific features that can be more suitable for a particular type of product. Thus, the most appropriate sterilization method for each product (and target microorganisms) should be assessed and carefully selected.

Improve the Electrical Properties of the ITO-PET Polymer by Plasma Technique

At present the applications of the conductive polymer are monitor, batteries and the sensors but there have been limitations due to the manufacturing costs, material inconsistencies, toxicity, poor solubility in solvents, and inability to directly melt process. Regarding these problems, in this research to studies the condition to enhance the conductive polymer were conducted via the carbon dioxide plasma technique coated on ITO-PET. The plasma power is 50, 75, 100, 125 and 150 watts in the vacuum conditions for periods 10, 20 and 30 mins respectively. The electrical properties were measured via the 4 point probe. The contact angle for analyzing the hydrophobic was analyzed. The result demonstrated that the power of the plasma and the time has influence on the conductive polymer. With the time for doping at 20 mins the current increased compare to the control item. However, with the time doping at 10 and 30 mins the current decreased. The maximum current at 10 mins doping is 22 mA at the 7 volts in the conduction of 75 watts plasma power. The contact angle of the ITO-PET polymer decrease from 110 degree to 44-95 degree. Henceforth when using the carbon dioxide plasma the phenomenal of hydrophilic increases.

Hydrophilic surface modification of polyacrylonitrile based membrane: effect of low temperature radio frequency carbon dioxide plasma

In general, polymeric membranes are hydrophobic in nature and hence are prone to fouling. Plasma treatment can impart functional groups on membrane surface making it more hydrophilic and hence fouling resistant. In plasma environment, carbon dioxide exhibits reactive properties with several exciting species and is likely to modify the membrane surface by imparting hydrophilicity. Low temperature plasma treatment using radio frequency discharge of carbon dioxide gas was employed to make polyacrylonitrile co-polymer membrane more hydrophilic. Permeability of treated membrane was increased by 2.2 times and it was retained up to 100 days. The surface morphology, structure and chemistry of the untreated and plasma-treated membranes were characterized extensively. Wettability of the surface was evaluated by contact angle measurement to show the improvement in hydrophilicity of plasma modified membrane. Effects of plasma conditions, namely, treatment time and power on membrane permeability and hydrophilicity were investigated. Hydrophilicity of modified membrane was enhanced by 22% and it was maintained up to 100 days. The effect of process variables on surface morphology of membrane was examined by scanning electron microscopy and atomic force microscopy. Surface etching due to plasma treatment was ensured by the loss of weight of the modified membranes. About 78% increase in average pore size of the treated membrane was obtained due to surface etching. The surface functionalization of unmodified and plasma modified polyacrylonitrile co-polymer membranes were investigated by X-ray photoelectron spectroscopy. Hydrophilic groups adhered to membrane surface after treatment was also identified.

In ovoL-leucine administration stimulates lipid metabolisms in heat-exposed male, but not female, chicks to afford thermotolerance

Thermal manipulation declined embryonic brain and liver concentrations of leucine (Leu). L-Leu in ovo injection afforded thermotolerance in male broiler chicks. This study aimed to examine the role of in ovo injection of L-Leu in metabolic functions, and differences between male and female broiler chicks in thermotolerance. L-Leu injection was performed in ovo on embryonic day (ED) 7 to reveal its role in metabolic activity in embryos and in post-hatch male and female broiler chicks under heat stress. To examine the metabolic activity of embryos, oxygen (O2) consumption, carbon dioxide (CO2) production, heat production and plasma metabolites were analyzed. Rectal temperature, food intake and plasma metabolites were also analyzed in heat-exposed (35 ± 1°C for 180min) male and female broiler chicks. It was found that O2 consumption, heat production, and plasma triacylglycerol (TG) and non-esterified fatty acid (NEFA) concentrations in ED 14 embryos were significantly increased by in ovo injection of L-Leu in comparison with the controls. Plasma glucose concentration was significantly increased in both male and female chicks under heat stress, but in ovo injection of L-Leu attenuated the increase in male chicks. In contrast, plasma TG, NEFA, and ketone body concentrations were significantly higher in male chicks injected in ovo with L-Leu, but not in similarly injected female chicks, compared with control chicks, all under heat stress. Rectal temperature and food intake were significantly lower in male, but not female, chicks under heat stress injected in ovo with L-Leu. In conclusion, in ovoL-Leu administration enhanced the prenatal metabolic rate and lipid metabolisms, which possibly appeared as sex-dependent fashion to facilitate thermotolerance in males. A reduction in heat production through lowered food intake in heat-exposed male, but not female chicks injected in ovo with L-Leu may help to afford thermotolerance in male broiler chicks under heat stress.

Making fuel and oxygen on Mars using plasma

Future colonists on Mars could use plasma technology to make their own oxygen. The atmosphere on Mars is 96 per cent carbon dioxide, says Vasco Guerra at the University of Lisbon in Portugal. This can be split to extract breathable oxygen and carbon monoxide, a fuel that could give us a gas station on the Red Planet, he says. He and his team calculate that creating a carbon dioxide plasma--a mush of ions made by passing an electric current through a gas--could split carbon dioxide from oxygen more easily on Mars than on Earth.

Enhancement of Fibroblasts Outgrowth onto Polycaprolactone Nanofibrous Grafted by Laminin Protein Using Carbon Dioxide Plasma Treatment

Enhancement of Fibroblasts Outgrowth onto Polycaprolactone Nanofibrous Grafted by Laminin Protein Using Carbon Dioxide Plasma Treatment

Improving crystallization and electron mobility of indium tin oxide by carbon dioxide and hydrogen dual-step plasma treatment

Obtaining high conductivity indium tin oxide (ITO) films simultaneously with a “soft-deposited” (low temperature, low ions bombardment) and cost-efficient deposition process are critical aspect for versatile photo-electronic devices application. Usually, the low-cost “soft-deposited” process could be achieved via evaporation technique, but with scarifying the conductivity of the films. Here, we show a CO2 and H2 two-step plasma (TSP) post-treatment applied to ITO films prepared by reactive thermal evaporation (RTE), allows to meet the special trade-off between the deposition techniques and the electrical properties. Upon treatment, an increase in electron concentration and electron mobility is observed, which subsequently resulting a low sheet resistivity. The mobility reaches high values of 80.9cm2/Vs for the TSP treated ∼100nm thickness samples. From a combination of X-ray photoelectron spectroscopy and opto-electronic measurements, it demonstrated that: during the TSP process, the first-step CO2 plasma treatment could promote the crystallinity of the RTE ITO films. While the electron traps density at grain boundaries of polycrystalline RTE ITO films could be passivated by hydrogen atom during the second-step H2 plasma treatment. These results inspired that the TSP treatment process has significant application prospects owing to the outstanding electrical properties enhancement for “soft-deposited” RTE ITO films.

CO2 Hydrogenation in a Dielectric Barrier Discharge Plasma Revealed

The hydrogenation of carbon dioxide in a dielectric barrier discharge plasma is studied with a one-dimensional fluid model. The spatially averaged densities of the most important end products formed in the CO2/H2 mixture are determined as a function of the initial gas mixing ratio. CO and H2O are found to be present at the highest densities and to a lower content also CH4, C2H6, CH2O, CH3OH, O2, and some other higher hydrocarbons and oxygenates. The main underlying reaction pathways for the conversion of the inlet gases and the formation of CO, CH4, CH2O, and CH3OH are pointed out for various gas mixing ratios. The CO2 conversion and the production of value added products is found to be quite low, also in comparison to a CO2/CH4 mixture, and this can be explained by the model.

Antimicrobial nature and healing behavior of plasma functionalized polyester sutures

This study deals with the development of bioactive poly(ethylene terephthalate) surgical suture by adopting the immobilization route with bioactive nanogels and chlorhexidine. Carbon dioxide plasma was used for the generation of carboxyl functionality on poly(ethylene terephthalate) surface for the immobilization of the bioactive components. The nanosilver nanogel was prepared using polyethylene glycol which helps in the reduction of silver ions into nanosilver as well as the stabilization of nanoparticles. The particle size of the nanogels, as evaluated by high-resolution transmission electron microscopy, was observed to be in the range of 10–50 nm. Surface functionalization of poly(ethylene terephthalate) filament was observed by attenuated total reflectance measurements and mechanical studies were investigated by Instron. Elemental analysis and surface topography were carried out by energy dispersive X-ray and atomic force microscopy. The cumulative release of silver from the dressing was found to be 68% of the total loading after 72 h. Coated sutures have excellent antimicrobial activity against both Escherichia coli and Staphylococcus aureus. In vivo wound healing and histopathology studies were carried out over a period of 72 h for skin wounds created on Swiss albino mice. Fast healing was observed in nanogel-treated wounds without any inflammatory effects on the newly generated skin. These sutures offer improved healing along with excellent antimicrobial properties and appear to be promising material against surgical infection.

Imaging of the Staphylococcus aureus Inactivation Process Induced by a Multigas Plasma Jet.

To identify mechanisms underlying the bacterial inactivation process by atmospheric nonthermal plasma using a unique plasma jet that can generate various gas plasmas, Staphylococcus aureus were irradiated with carbon dioxide plasma, which produces a large amount of singlet oxygens, and nitrogen plasma, which produces a large amount of OH radicals. And damaged areas of plasma-treated bacteria were observed by field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. As a result, bacteria were damaged by both gas plasmas, but the site of damage differed according to gas species. Therefore, it suggests that singlet oxygen generated by carbon dioxide plasma or other reactive species caused by singlet oxygen contributes to the damage of internal structures of bacteria through the cell wall and membrane, and OH radicals generated by nitrogen plasma or other reactive species derived from OH radicals contribute to damage of the cell wall and membrane.

Modify the Schottky contact between fluorine-doped tin oxide front electrode and p-a-SiC:H by carbon dioxide plasma treatment

Carbon dioxide plasma (COP) treatment of a fluorine-doped tin oxide (SnO2:F, FTO) front electrode was used for the fabrication of p–i–n hydrogenated amorphous silicon (a-Si:H) solar cells. The oxygen and carbon monoxide radicals in COP play important roles of de-doping and doping effects on the surface of FTO, respectively. Through changing the COP treatment time, the de-doping and doping effects could alter the number of oxygen vacancies for both the bulk and the surface of FTO, resulting in an increase in the work function (WF) and a decrease in the Schottky barrier at the p-a-SiC:H/FTO interface. Due to an increase in the WF from 4.16eV to 4.34eV after 95s treatment, the open circuit voltage (Voc) of the a-Si:H solar cells increased from 915mV to 965mV and the fill factor (FF) increased from 67.7% to 74.4%. Although the short-circuit current density (Jsc) decreased from 11.76mA/cm2 to 10.36mA/cm2 after 95s COP treatment due to the weakness of Burstein–Moss (BM) shift and the recombination at FTO surface, the conversion efficiency of the a-Si:H solar cell was enhanced by 12.24% after 45s COP treatment, accompanied by improving the Voc and FF with almost constant Jsc.

Hydrogen Production by Hydrolysis of NaBH4 with Cr-Ni-W-B Catalyst: Effects of Cold Plasma and Chromium Content

Abstract In this study, the hydrogen generation from the hydrolysis of NaBH4 with Cr0.0125-Ni-W-B catalyst prepared in the presence of cold plasma was investigated based on Cr content, NaBH4 concentration, NaOH concentration, temperature, plasma applying time and plasma gases effects. The results of the activity tests indicate that the choice of Cr and the catalyst composition greatly influenced the activity as well as the selectivity for hydrogen generation from the hydrolysis of NaBH4. The Cr0.0125-Ni-W-B catalyst was treated with argon, nitrogen and carbon dioxide plasma at different treatment times. The catalysts were characterized using SEM, BET surface area measurement and XRD.

Disintegration of Carbon Dioxide Molecules in a Microwave Plasma Torch.

A pure carbon dioxide torch is generated by making use of 2.45 GHz microwave. Carbon dioxide gas becomes the working gas and produces a stable carbon dioxide torch. The torch volume is almost linearly proportional to the microwave power. Temperature of the torch flame is measured by making use of optical spectroscopy and thermocouple. Two distinctive regions are exhibited, a bright, whitish region of high-temperature zone and a bluish, dimmer region of relatively low-temperature zone. Study of carbon dioxide disintegration and gas temperature effects on the molecular fraction characteristics in the carbon dioxide plasma of a microwave plasma torch under atmospheric pressure is carried out. An analytical investigation of carbon dioxide disintegration indicates that substantial fraction of carbon dioxide molecules disintegrate and form other compounds in the torch. For example, the normalized particle densities at center of plasma are given by nCO2/nN = 6.12 × 10−3, nCO/nN = 0.13, nC/nN = 0.24, nO/nN = 0.61, nC2/nN = 8.32 × 10−7, nO2/nN = 5.39 × 10−5, where nCO2, nCO, nC, nO, nC2, and nO2 are carbon dioxide, carbon monoxide, carbon and oxygen atom, carbon and oxygen molecule densities, respectively. nN is the neutral particle density. Emission profiles of the oxygen and carbon atom radicals and the carbon monoxide molecules confirm the theoretical predictions of carbon dioxide disintegration in the torch.

Effect of CO2 plasma exposure on physico-chemical properties of porous polycaprolactone scaffold

Carbon dioxide plasma was employed for the surface modification of tubular poly(caprolactone) porous matrix. Effect of plasma exposure over surface functionality, mechanical properties, surface morphology, pore size and crystal structure was investigated. Plasma modification is useful in achieving desired surface chemical properties without much alteration in the bulk properties of material. This process yields a porous tubular structure of 40 ± 11 MPa tensile strength, 464 ± 101 % tensile strain, 226 ± 41 g f suture retention strength and 52 % crystallinity. Profound influence of plasma exposure time over pore size and crystal form transition has been observed. Surface became hydrophilic in nature as evident from the low contact angle with 60 s exposure. The resulted surface-modified PCL tubular porous matrix with –COOH density of 40 nM/cm2 can anchor maximum of 2.67 mg/cm2 gelatin on the surface.

Epidural levobupivacaine alone or combined with different morphine doses in bitches under continuous propofol infusion

The aim of this study was to assess the cardiopulmonary, analgesic, adverse effects, serum concentration of cortisol and plasma levels of levobupivacaine and morphine in bitches undergoing propofol anesthesia and epidural analgesia with levobupivacaine alone or combined with morphine. This was a randomized 'blinded' prospective clinical study using 32 adult bitches weighing 9.8±4.1kg that were admitted for elective ovariohysterectomy. Twenty minutes after administration of acepromazine and midazolam, anesthesia was induced with propofol (4mg kg-1) and maintained by a continuous rate infusion (CRI). Each animal was randomly assigned to one of four epidural groups: GL = levobupivacaine alone (0.33mg kg-1); GLM0.1 = levobupivacaine and morphine (0.1mg kg-1); GLM0.15 = levobupivacaine and morphine (0.15mg kg-1); and GLM0.2 = levobupivacaine and morphine (0.2mg kg-1). Variables obtained during anesthesia were heart rate, respiratory rate, systolic, mean and diastolic arterial blood pressures, oxyhemoglobin saturation, inspired oxygen fraction, end-tidal carbon dioxide tension, blood gases, serum cortisol, and plasma levels of levobupivacaine and morphine. The onset and duration times of the blockade were recorded. Arterial pressures were significantly increased in all groups at the times of ovarian pedicle clamping. There was a decrease in pH, together with an increase in both PaO2and PaCO2 over time. Serum cortisol levels were increased in TESu compared to TB, T30 and TR. Limb spasticity, muscle tremors, opisthotonos and diarrhea were observed in some animals during propofol infusion and ceased with the end of CRI. Reactions happened at different moments and lasted for different periods of time in each individual. Epidural with levobupivacaine alone or combined with morphine allowed for ovariohysterectomy to be performed under low propofol infusion rates, with minimal changes in cardiovascular variables and in serum cortisol levels. Adverse effects were observed in very few animals in each group.

Microbial Inactivation in the Liquid Phase Induced by Multigas Plasma Jet.

Various gas atmospheric nonthermal plasmas were generated using a multigas plasma jet to treat microbial suspensions. Results indicated that carbon dioxide and nitrogen plasma had high sterilization effects. Carbon dioxide plasma, which generated the greatest amount of singlet oxygen than other gas plasmas, killed general bacteria and some fungi. On the other hand, nitrogen plasma, which generated the largest amount of OH radical, killed ≥6 log of 11 species of microorganisms, including general bacteria, fungi, acid-fast bacteria, spores, and viruses in 1–15 min. To identify reactive species responsible for bacterial inactivation, antioxidants were added to bacterial suspensions, which revealed that singlet oxygen and OH radicals had greatest inactivation effects.

Fuel Gas Production from Biomass Sources by Radio Frequency In-Liquid Plasma Method

Cellulose is a kind of saccharide that is the main component in cell walls of plants and therefore is the organic compound that exists in the largest amount in nature. The purpose of this experiment is to convert cellulose to a fuel. Radio frequency (RF) in-liquid plasma is generated in a cellulose distributed solution and a glucose solution, and the generation gas rate is measured. While hydrogen is the main gas generated by the plasma breakdown, carbon monoxide, carbon dioxide, and low-grade flammable gases are also produced. In the glucose water solution or the glucose distributed solution, the solution itself evaporates and decomposes inside the plasma but since the saccharides are non-volatile, they cannot penetrate into the plasma and are not decomposition. However, when the cellulose is at concentrations of 30 wt% or more, it becomes granular and can directly enter the plasma as a solid, where the plasma decomposes the cellulose itself, significantly increasing the amount of gas generated. In addition, the spectrometry of the plasma emission shows the solution after the creation of plasma has the ability to absorb ultraviolet light.

Carbon Dioxide Plasma as a Versatile Medium for Purification and Functionalization of Vertically Aligned Carbon Nanotubes

Three-dimensional (3D) architectures obtained by the structural assembly of 1D nanomaterials are regarded as the next generation building blocks for sensors, electronics, photonics, and bioelectronic applications. Purification and functionalization of such 3D ordered structures are crucial for realizing their full potential. Plasma functionalization, compared to any solution based process, is favorable in retaining the alignment while functionalizing such structures. However, the commonly employed plasma processes like O2 or Ar plasma can be highly detrimental to well-aligned ordered nanostructures and thus might affect the properties intimately associated with their 3D structure. Here, for the first time, we investigate the mild nature of a radio frequency CO2 gas plasma as an effective source for purification and functionalization of vertically aligned CNT structures and study the effects of this functionalization onto the purification and functionalization by physical and chemical techniques (HRTEM, XPS, Raman). We found that CO2 plasma selectively etches the amorphous carbon present in the vertically aligned CNT structure. Moreover, it is as effective as the widely used but more aggressive O2 plasma in functionalizing the CNT. Unlike an O2 or Ar plasma, CO2 plasma has the tremendous advantage of retaining the structural integrity of the CNT structures.