Helium Gas Plasma Research Articles

Experience With J-Plasma Device in Achieving Complete Cytoreduction in Patients With Ovarian Cancer.

Ovarian cancer remains one of the most lethal malignancies in women. Optimal surgical cytoreduction is the most important prognostic factor of survival in patients with advanced ovarian cancer. The helium gas plasma device (J-Plasma) has recently been introduced into surgical treatment of these patients with some promising results. The aim of this study was to evaluate the utility of J-Plasma in the debulking surgery of patients with ovarian cancer. A single center retrospective analysis of the characteristics of patients with ovarian cancer who had cytoreductive surgery with the use of J-Plasma device from January of 2020 until July of 2022 was conducted. A total of 13 patients were included in our study. Six patients were treated with primary debulking surgery, whereas seven underwent interval debulking surgery after neoadjuvant chemotherapy. Complete cytoreduction was achieved in nine patients (64%), and CC-1 in four patients. Most of the patients did not face any major complications; only 1 patient suffered from small bowel fistula that needed relaparotomy. J-Plasma can safely be used in ovarian cancer debulking surgeries performed by gynecologic oncologists in tertiary centres. This technology can safely increase the complete cytoreduction rates.

Effects of Cold Atmospheric Plasma on Infectious Diabetic Wound Healing in Rat Models

Objectives: Patients with diabetes often suffer from chronic wounds which can occur due to the impairment of wound healing in these patients. Scientists have been trying to address this issue by using wide spectrum of antibiotics and drugs. However, overusing antibiotics in recent years has led to antibiotic resistant crisis; therefore, there is an urgent need to develop new approaches in order for controlling microbial infections in diabetic patients. This study aimed to determine if cold plasma was effective in wound healing in the infectious diabetic conditions. Material and Methods: In this experimental study, 40 adult male rats with diabetes infected with Staphylococcus aureus were included. The animals were randomly divided into two groups of 20 rats and four sub-groups (i.e., day 3rd, day 7th, day 14th, and day 21st). The rats in the treatment group were exposed to helium plasma irradiated for 3 minutes per day for 21 days. Wound healing in the samples was evaluated using five healing indexes including epithelium formation, Inflammatory cells, new vascularization, fibroblast, and collagen formation. Results: A significant difference (P<0.05) was found between the indexes in the plasma radiation group compared to the control group. The results showed that the speed of wound healing in the group treated with cold helium gas plasma was higher than that in the control group. Collagen formation was always completed faster in the helium plasma group, indicating the positive effects of helium plasma on infected diabetic wounds. Conclusions: Helium plasma was remarkable effective in healing wound and controlling infections in diabetic rats.

Not all Radiofrequency Devices Are Created Equal: A Thermal Assessment.

Not all Radiofrequency Devices Are Created Equal: A Thermal Assessment.

Beneficial effects of cold atmospheric plasma on inflammatory phase of diabetic foot ulcers; a randomized clinical trial.

The healing process is impaired in diabetic wounds like the other types of chronic wounds. Cytokines, and growth factors are valuable candidates for determination of wound vitality or duration. The aim of this study is to introduce a beneficial method to stop the inflammatory phase and infection in the wound healing process for accelerating the treatment of diabetic foot ulcers. As a randomized controlled trial, 44 patients with diabetic foot ulcers were selected and randomized. Twenty-two patients received standard care and rest of them received SC (standard care) + CAP (cold atmospheric plasma), n = 22). Clinical examination was performed to assess the status of peripheral nerves and arteries for all patients. Cold plasma jet was used as a source of helium gas plasma generator. Plasma was irradiated on the wound 5min, 3 times a week for 3 consecutive weeks. Applying a plasma jet was effective in wound healing. The level of inflammatory cytokines was changed. Moreover, after applying plasma the mean expression of these variables was significantly decreased (P = 0.001). Following the plasma treatment, the level of cytokines such as IL-1 (39.44 ± 7.67), IL-8 (368.30 ± 82.43), INF-γ (17.03 ± 2.62), TNFα (22.75 ± 4.02) has decreased, inflammatory factors have ameliorated over three weeks, and accelerate wound healing. After CAP exposure, the mean of the mean fraction of bacterial load counts was significantly decreased. The effect of plasma irradiation on infectious diabetic foot ulcer was decreased bacterial load then accelerated wound healing by effecting on inflammatory phase in diabetic foot ulcers.

Low Power Cuk Inverters

The paper describes a low power cuk inverter for atmospheric Helium plasma (He). A high frequency was used in order to drive the pulse width modulation circuit. The average output current consumption (AOCC) was modified from (10A) up to (20A) by increasing the duty ratio from (0.10) up to (0.30) for the atmospheric Helium gas plasma. The switching frequency of the cuk inverter was fixed at (25KHz).

Direct evidence of mismatching effect on H emission in laser-induced atmospheric helium gas plasma

A time-resolved orthogonal double pulse laser-induced breakdown spectroscopy (LIBS) with helium surrounding gas is developed for the explicit demonstration of time mismatch between the passage of fast moving impurity hydrogen atoms and the formation of thermal shock wave plasma generated by the relatively slow moving major host atoms of much greater masses ablated from the same sample. Although this so-called “mismatching effect” has been consistently shown to be responsible for the gas pressure induced intensity diminution of hydrogen emission in a number of LIBS measurements using different ambient gases, its explicit demonstration has yet to be reported. The previously reported helium assisted excitation process has made possible the use of surrounding helium gas in our experimental set-up for showing that the ablated hydrogen atoms indeed move faster than the simultaneously ablated much heavier major host atoms as signaled by the earlier H emission in the helium plasma generated by a separate laser prior to the laser ablation. This conclusion is further substantiated by the observed dominant distribution of H atoms in the forward cone-shaped target plasma.

A comprehensive study of H emission in a TEA CO2 laser-induced helium gas plasma for highly sensitive analysis of hydrogen in metal samples

Our previous work on an innovative method of hydrogen (H) analysis using the specific characteristics of a TEA CO2 laser, “selective detection method of H”, has been improved to realize a high H sensitive analysis with a detection limit of several µg/g. For this purpose, first, we clarified the origin of the H emission disturbance coming from H2O molecules; namely, we showed that most of the H emission came from H2O on the metal surface and not from H2O existing in the surrounding gas when we formed a laser-induced gas plasma. Second, the difference in the emission characteristics between the H emission from H2O on the metal surface and H emission from inside in sample was studied to determine the optimum gating time of the optical multi-channel analyzer (OMA). Third, the gas plasma was totally covered by fresh helium gas using a big pipe (5 mm in diameter) and by flowing a high amount of He (10 l/min). Also, we demonstrated that our methods could potentially be applied to H analysis in steel samples, where an H analysis with a sensitivity of less than 1 µg/g is required without employing a heating process, by removing H2O on the sample surface with the aid of defocused TEA CO2 laser irradiation. Thus, we stress that our method can be used for a highly sensitive, in-situ analysis of H for metal samples.

The effect of wool surface and interior modification on subsequent photostability

AbstractWool surface and interior modification can impart favorable properties, such as felting/shrink resistance, settability, or improved affinity for dyes. However, in principle such modification may have an either beneficial or adverse effect on the subsequent photostability of the modified wool. In this study, a range of representative physical and chemical modification approaches including the use of helium gas plasma, papain, acylation with acid anhydride, and permanganate oxidation were applied to wool fabrics, and the subsequent effects characterized using scanning electron microscopy, FTIR‐ATR, contact angle goniometry, fluorescence spectrophotometry, and tensile strength test. The relative photostability of control and treated wool were evaluated in terms of coloration changes under UVA, UVB, and blue light irradiation. We have shown that the subsequent photostability of modified wool fabrics is highly dependent on the modification type, and this factor should be carefully considered in the design and application of wool treatments. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Quantitative Analysis of Deuterium in Zircaloy Using Double-Pulse Laser-Induced Breakdown Spectrometry (LIBS) and Helium Gas Plasma without a Sample Chamber

A crucial safety measure to be strictly observed in the operation of heavy-water nuclear power plants is the mandatory regular inspection of the concentration of deuterium penetrated into the zircaloy fuel vessels. The existing standard method requires a tedious, destructive, and costly sample preparation process involving the removal of the remaining fuel in the vessel and melting away part of the zircaloy pipe. An alternative method of orthogonal dual-pulse laser-induced breakdown spectrometry (LIBS) is proposed by employing flowing atmospheric helium gas without the use of a sample chamber. The special setup of ps and ns laser systems, operated for the separate ablation of the sample target and the generation of helium gas plasma, respectively, with properly controlled relative timing, has succeeded in producing the desired sharp D I 656.10 nm emission line with effective suppression of the interfering H I 656.28 nm emission by operating the ps ablation laser at very low output energy of 26 mJ and 1 μs ahead of the helium plasma generation. Under this optimal experimental condition, a linear calibration line is attained with practically zero intercept and a 20 μg/g detection limit for D analysis of zircaloy sample while creating a crater only 10 μm in diameter. Therefore, this method promises its potential application for the practical, in situ, and virtually nondestructive quantitative microarea analysis of D, thereby supporting the more-efficient operation and maintenance of heavy-water nuclear power plants. Furthermore, it will also meet the anticipated needs of future nuclear fusion power plants, as well as other important fields of application in the foreseeable future.

Excitation Mechanism of H, He, C, and F Atoms in Metal-Assisted Atmospheric Helium Gas Plasma Induced by Transversely Excited Atmospheric-Pressure CO2Laser Bombardment

To clarify the excitation mechanism of hydrogen in transversely excited atmospheric-pressure (TEA) CO2 laser-induced helium gas plasma, atomic emission characteristics of H, C, F, and He were studied using a Teflon sheet (thickness of 2 mm) attached to a metal subtarget. The TEA CO2 laser (750 mJ, 200 ns) was focused on the Teflon sheet in the surrounding He gas at 1 atm. Atomic emissions of H, C, F, and He occurred with a long lifetime, a narrow spectrum width, and a low-background spectrum. The correlation emission intensity curves of H–He and F–He indicated a parabolic functions. To explain the emission characteristics, we offered a model in which helium metastable atoms (He*) play an important role in the excitation processes; namely, atoms collide with helium metastable atoms (He*) to be ionized by the Penning effect, and then recombine with electrons to produce excited states, from which atomic emissions occur.

Excitation Mechanism of H, He, C, and F Atoms in Metal-Assisted Atmospheric Helium Gas Plasma Induced by Transversely Excited Atmospheric-Pressure CO2 Laser Bombardment

To clarify the excitation mechanism of hydrogen in transversely excited atmospheric-pressure (TEA) CO2 laser-induced helium gas plasma, atomic emission characteristics of H, C, F, and He were studied using a Teflon sheet (thickness of 2 mm) attached to a metal subtarget. The TEA CO2 laser (750 mJ, 200 ns) was focused on the Teflon sheet in the surrounding He gas at 1 atm. Atomic emissions of H, C, F, and He occurred with a long lifetime, a narrow spectrum width, and a low-background spectrum. The correlation emission intensity curves of H–He and F–He indicated a parabolic functions. To explain the emission characteristics, we offered a model in which helium metastable atoms (He*) play an important role in the excitation processes; namely, atoms collide with helium metastable atoms (He*) to be ionized by the Penning effect, and then recombine with electrons to produce excited states, from which atomic emissions occur.

Rapid Analyses of Tiny Amounts of Powder Samples Using Transversely Excited Atmospheric CO2 Laser-Induced Helium Gas Plasma with the Aid of High-Vacuum Silicon Grease as a Binder on a Metal Subtarget

Rapid quantitative analyses of powder samples available in tiny amounts have successfully been conducted by utilizing a transversely excited atmospheric (TEA) CO2 laser-induced He gas plasma. In this study, 4 mg of powder sample was homogeneously mixed with 4 mg of high-vacuum silicon grease and the silicon grease–mixed powder sample (SMP) was painted on a metal surface, which serves as a subtarget. The grease functions to strongly bind the powder and to suppress blow-off of the powder particles. When a TEA CO2 laser (750 mJ, 10.6 μm, 200 ns) was directly focused on the metal subtarget in He gas at 1 atmosphere, a hightemperature He gas plasma was induced, producing a profusion metastable He atoms. It is assumed that the powder particles together with the silicon grease were vaporized to be effectively atomized and excited through metastable He atoms. The result revealed that this technique can be widely employed in the rapid semi-quantitative analyses of powder samples present in minute amounts. A quantitative analysis of loam soil containing different concentrations of Cu was successfully demonstrated, resulting in a good linear calibration curve. The detection limits of Cr and Pb in loam soil were approximately 4 and 13 mg/kg, respectively. Also, we confirmed that this technique can be applied to check the quality of commercial products such as gold film (Au foil), mineral supplement tablets, and prestigious cosmetic powders.

Emission characteristics of hydrogen in atmospheric helium gas plasma induced by TEA CO2 laser bombardment on zircaloy sample containing hydrogen

The most difficult issue as regards hydrogen (H) analysis using the laser-induced plasma technique is the disturbance of H emission by H2O molecules. This problem is essentially solved in this paper by employing a novel technique that makes use of the specific characteristics of a TEA CO2 laser. Thus, a small helium gas plasma was produced by focusing a TEA CO2 laser onto a zircaloy surface containing H atoms. High-purity helium (He) gas was passed over the focusing point during the experiment so that the plasma was totally covered by the He gas and the H2O molecules remaining in the surrounding gas could not attack the plasma region. This technique ensures that only hydrogen atoms come out from the melted region of the sample surface, and are excited via metastable He atoms. This method has allowed us to confirm that H alpha (Hα), H beta (Hβ), H gamma (Hγ), and H delta (Hδ) emission can clearly be detected from a hydrogen-containing zircaloy sample with no interference from host emission lines or the H emission arising from H2O. The intensity ratio of Hα, Hβ, and Hγ was compared with that obtained for a low pressure hydrogen discharge lamp.

Hydrogen analysis in metal samples by selective detection method utilizing TEA CO2 laser-induced He gas plasma

When a Transversely Excited Atmospheric (TEA) CO2 laser (energy of 1.5 J, pulse duration of 200 ns) was focused on a metal sample surface containing hydrogen (H) in He gas at 1 atm, a strong helium gas plasma was produced and only H atoms came out of the sample. The H atoms then moved into the helium gas plasma to be excited through meta-stable helium atoms. Using this technique, an excellent linear calibration curve with zero intercept was made using zircalloy-2 samples containing H (100–600 ppm), where the compensation method was made using an emission intensity of O I 777.1 nm in order to subtract the H emission intensity coming from unwanted H2O. It should be emphasized that this technique has a possibility to realize highly sensitive analysis of H with a detection limit of less than 1 ppm because of its selective detection.

Detection of deuterium and hydrogen using laser-induced helium gas plasma at atmospheric pressure

An experimental study on gas analysis by means of laser-induced breakdown spectroscopy was conducted using a Nd-yttrium aluminum garnet laser (1,064 nm, 120 mJ, 8 ns) and helium host gas at atmospheric pressure on a sample of mixed water (H2O) and heavy water (D2O) in vapor form. It was shown that completely resolved hydrogen (Hα) and deuterium (Dα) emission lines that are separated by only 0.179 nm could be obtained at a properly delayed detection time when the charged particles responsible for the strong Stark broadening effect in the plasma have mostly disappeared. It is argued that the helium metastable excited state plays an important role in the hydrogen excitation process.

Behavior of helium gas in the LHD vacuum chamber

In general, helium gas does not remain on vacuum chamber walls because of its small activation energy. However, outgassing of helium gas from the walls has been observed in the LHD plasma vacuum chamber with a very long time constant after helium glow discharge cleaning (GDC), and absorption of helium atoms has been observed in plasma discharge experiments using helium gas. The helium partial pressure before the daily experiments was determined only by the gas species of the last GDC. No dependence has been found between the helium partial pressure and the species of the fueling gas of the last plasma experiment fueling gas. Considering that the outgassing rate of the helium gas is almost the same each morning after He GDC, the retention of helium atoms in the wall after the GDC is almost at the same level. The concentration of helium atoms in the wall before the daily experiments is estimated. The outgassing rate after the GDC is 2×10 −4 Pa m 3/s and the concentration is 4.7×10 16 atoms/cm 2. These results are of the same order as in another experiments. During helium gas plasma experiments, about a half of the amount of the inlet gas disappears with the missing particles remaining in the wall. The stainless steel wall, which is saturated with He GDC, may still have the capacity to trap high energy helium atoms. However, the energy dependence of trapping helium atoms presently is not clear.

Surface modification of polyethylene by radiation‐induced grafting for adhesive bonding. V. Comparison with other surface treatments

AbstractHelium gas plasma treatment of low‐density polyethylene (LDPE) yields much lower peel strength than oxidative treatment using chromic acid and oxygen gas plasma. The practical adhesion, the bondability retention, and the bond durability of oxidatively treated LDPE sheets, bonded with epoxy adhesives, have been compared with those of partially hydrolyzed LDPE–methyl acrylate surface grafts. The oxidized surfaces easily lose the bondability by light rubbing with tissue paper, solvent extraction, heat aging, and artifical weathering, whereas the grafted surfaces retain the bondability. The bondability loss is due to removal of the oxidized layer, and the bondability retention is due to retention of the surface homopolymer layer. Conventional antioxidants stabilize the grafted but not the oxidized surfaces against thermal oxidative degradation. The grafted LDPE joints have much higher bond durability in humid environments than those of the oxidized LDPE joints. The dry and wet peel strengths of oxidized LDPE joints are greatly improved by application of primers consisting of a base epoxy resin and organic solvents. An adhesion mechanism involving penetration of epoxy adhesives into the oxidized layers and subsequent reinforcement of the layers by curing of the penetrated epoxy is proposed.