Low-temperature Plasma Research Articles

Experimental study of low temperature plasma synergistic catalyst for treatment of DEP in water

In this paper, CuO/Al2O3 catalysts were prepared by impregnation method, and the catalysts were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) techniques. The effects of loading capacity and roasting temperature on the performance of CuO/Al2O3 synergistic low-temperature plasma degradation of DEP in water were investigated during the catalyst preparation process, and the influences of the catalyst dosage, input voltage in the synergistic system, aeration flow rate, and the initial concentration of the reactants on the removal effect of DEP were also explored. The results showed that the removal rate of DEP by the synergistic system tended to increase and then decrease with the increase of catalyst loading and roasting temperature. The degradation rate of DEP could reach 94.08 % under the optimal conditions of 400 °C, 30 % catalyst loading, concentration of 10 mg/L, input voltage of 30 kV, and aeration flow rate of 200 L/h. And the degradation pathway of DEP was inferred by mass spectrometry detection.

Structure and Properties of Bioactive Titanium Dioxide Surface Layers Produced on NiTi Shape Memory Alloy in Low-Temperature Plasma.

The NiTi alloy, known for its shape memory and superelasticity, is increasingly used in medicine. However, its high nickel content requires enhanced biocompatibility for long-term implants. Low-temperature plasma treatments under glow-discharge conditions can improve surface properties without compromising mechanical integrity. This study explores the surface modification of a NiTi alloy by oxidizing it in low-temperature plasma. We examine the impact of process temperatures and sample preparation (mechanical grinding and polishing) on the structure of the produced titanium oxide layers. Surface properties, including topography, morphology, chemical composition, and bioactivity, were analyzed using TEM, SEM, EDS, and an optical profilometer. Bioactivity was assessed through the deposition of calcium phosphate in simulated body fluid (SBF). The low-temperature plasma oxidization produced titanium dioxide layers (29-55 nm thick) with a predominantly nanocrystalline rutile structure. Layer thickness increased with extended processing time and higher temperatures (up to 390 °C), though the relationship was not linear. Higher temperatures led to thicker layers with more precipitates and inhomogeneities. The oxidized layers showed increased bioactivity after 14 and 30 days in SBF. Low-temperature plasma oxidation produces bioactive titanium oxide layers on NiTi alloys, with a structure and properties that can be tuned through process parameters. This method could enhance the biocompatibility of NiTi alloys for medical implants.

Dielectric Barrier Plasma Discharge Exsolution of Nanoparticles at Room Temperature and Atmospheric Pressure.

Exsolution of metal nanoparticles (NPs) on perovskite oxides has been demonstrated as a reliable strategy for producing catalyst-support systems. Conventional exsolution requires high temperatures for long periods of time, limiting the selection of support materials. Plasma direct exsolution is reported at room temperature and atmospheric pressure of Ni NPs from a model A-site deficient perovskite oxide (La0.43Ca0.37Ni0.06Ti0.94O2.955). Plasma exsolution is carried out within minutes (up to 15min) using a dielectric barrier discharge configuration both with He-only gas as well as with He/H2 gas mixtures, yielding small NPs (<30nm diameter). To prove the practical utility of exsolved NPs, various experiments aimed at assessing their catalytic performance for methanation from synthesis gas, CO, and CH4 oxidation are carried out. Low-temperature and atmospheric pressure plasma exsolution are successfully demonstrated and suggest that this approach could contribute to the practical deployment of exsolution-based stable catalyst systems.

Multifunctional surface treatment of boron nitride nanotube‐coated polyimide films with atmospheric‐pressure cold plasma

AbstractPolyimide (PI) surfaces coated with and without boron nitride nanotubes (BNNTs) were treated using an atmospheric‐pressure cold plasma in open air. This treatment increased the surface wettability of the PI, measured by a decrease in water contact angle from 68° to 16°, resulting in a more uniform BNNT coating and improved surface adhesion. The plasma treatment of the BNNT‐coated PI surfaces also effectively removed residual polymer surfactants used for BNNT dispersion in water, without causing any thermal damage due to the low plasma and PI's surface temperatures of 350 and 300 K, respectively. The reactive oxygen species in the plasma, such as hydroxyl molecules and oxygen atoms, played an important role in these processes. Atmospheric‐pressure plasma can be employed in various applications in which thermally weak polymer‐based substrates are coated with BNNTs.

Implementation of low temperature spectrometers for the JET high resolution Thomson scattering diagnostic for disruption plasma measurements.

This work presents a system upgrade of the High Resolution Thomson Scattering (HRTS) diagnostic [Pasqualotto etal., Rev. Sci. Instrum. 75, 3891-3893 (2004)] on JET that allows it to measure low temperature (1-500eV) plasma pre- and post-Thermal quench (TQ), which would help us further understand the Shattered Pellet Injection (SPI) physics. The upgrade was done by connecting optic fibers from the original HRTS system to four spectrometers specialized in measuring low temperature plasmas. The upgraded system allows for the measurement of low temperature plasma at up to 12 spatial points, which can be flexibly distributed throughout the JET outer midplane profile during the dedicated SPI experiments. In other JET experiments, four previously unused groups of fibers were used to measure the central plasma to provide disruption data without changing the standard HRTS system. The low temperature Thomson scattering system was installed, commissioned, and cross-calibrated against the standard HRTS diagnostic in a calibration pulse. The system worked reliably during the JET experiments and provided electron density and temperature profiles for pre- and post-TQ low temperature plasmas in the SPI campaign.

Variations of plasma potential in RF discharges with DC-grounded electrode

The self-bias voltage Vbias and the plasma potential Vp are the key parameters to control plasma-wall interactions in radio-frequency (RF) asymmetric plasma discharges. Knowing these two parameters allows to monitor the ion energy distribution on the electrode surface. However, in a direct current (DC) coupled plasma, the plasma potential increased to hundreds of volts while no more Vbias developed on the driven electrode. In addition, the plasma potential is strongly impacted by the electrode-wall area ratio. Several analytical or semi-analytical models exist to explain this phenomenon and to approximate the plasma potential, knowing the electrode-wall area ratio considering capacitive sheaths or a combination of resistive and capacitive sheaths. The Vp and several other plasma parameters were investigated experimentally with a Langmuir probe and a Retarding field energy analyser for different electrode/wall area ratios in low-temperature RF plasma. The validity of the models was studied for an extensive range of area ratios with different pressures and RF driving amplitude. Moreover, the presence of strong stochastic heating of the plasma for area ratios below 6 was evidenced by an increased ion flux and an increased electron temperature.

Acceleration of particle-in-cell simulations using sparse grid algorithms. II. Application to partially magnetized low temperature plasmas

In Paper I [Garrigues et al., Phys. Plasmas 31, 073907 (2024)], we have extended the sparse PIC approach already used in the literature with the offset scheme to reduce the grid-based error. In this study, we demonstrate the ability of the offset sparse PIC algorithm to model partially magnetized low-temperature plasmas by reducing the grid-based error. In the context of multi-cusp magnetic field configurations, the offset scheme reduces the error of the current collected at the walls to less than 5% for more of the plasma conditions encountered in ion source applications. The formation of a double layer in the sheath region is also captured. In the context of the electron drift instability that occurs in the Hall thruster, the plasma properties as well as the ion velocity distribution function can be retrieved with a high enough precision without considering an initial regular grid with a smaller mesh resolution. The results also highlight the advantage of combining the electric potential at the nodes of the regular grid instead of directly combining the electric field from the component grids. Compared to the regular PIC algorithm, the typical speed-up factor is about three for a number of mesh nodes of 2562 and five for 5122.

Machine learning for parameters diagnosis of spark discharge by electro-acoustic signal

Discharge plasma parameter measurement is a key focus in low-temperature plasma research. Traditional diagnostics often require costly equipment, whereas electro-acoustic signals provide a rich, non-invasive, and less complex source of discharge information. This study harnesses machine learning to decode these signals. It establishes links between electro-acoustic signals and gas discharge parameters, such as power and distance, thus streamlining the prediction process. By building a spark discharge platform to collect electro-acoustic signals and implementing a series of acoustic signal processing techniques, the Mel-Frequency Cepstral Coefficients (MFCCs) of the acoustic signals are extracted to construct the predictors. Three machine learning models (Linear Regression, k-Nearest Neighbors, and Random Forest) are introduced and applied to the predictors to achieve real-time rapid diagnostic measurement of typical spark discharge power and discharge distance. All models display impressive performance in prediction precision and fitting abilities. Among them, the k-Nearest Neighbors model shows the best performance on discharge power prediction with the lowest mean square error (MSE = 0.00571) and the highest -squared value ( ). The experimental results show that the relationship between the electro-acoustic signal and the gas discharge power and distance can be effectively constructed based on the machine learning algorithm, which provides a new idea and basis for the online monitoring and real-time diagnosis of plasma parameters.

Elastic cross section data for precursor molecules used in low-temperature plasmas: Sn(CH3)4 and Ga(CH3)3

Tetramethyltin [Sn(CH3)4] and trimethylgallium [Ga(CH3)3] are important source molecules of Sn and Ga atoms which are used in manufacturing techniques involving low-temperature plasmas. Accurate numerical modeling of plasma environments requires a comprehensive set of electron scattering cross sections by these precursor molecules. Here, we report the elastic integral, differential, and momentum transfer cross sections for electron collisions with Sn(CH3)4 and Ga(CH3)3 for energies ranging from 0 to 30 eV. Our calculations were carried out with the Schwinger multichannel method implemented with pseudopotentials and considered two levels of approximation in our calculations, namely static-exchange and static-exchange plus polarization. We identified three shape resonances for Sn(CH3)4 and one clear low-lying resonance for Ga(CH3)3. The low-energy behavior of the s-wave cross section and eigenphase was investigated and, for both molecules, we found evidence of a Ramsauer–Townsend (RT) minimum and a virtual state. Our results indicate that negative differential conductivity would occur in a gas composed of Sn(CH3)4. On the other hand, this effect would be suppressed in a gas of Ga(CH3)3 due to an overlap between the position of the RT minimum and the shape resonance in the momentum-transfer cross section.

Enhancing colloidal stability of nanodiamond via surface modification with dendritic molecules for optical sensing in physiological environments

Pre-treatment of diamond surface in low-temperature plasma for oxygenation and in acids for carboxylation was hypothesized to promote the branching density of the hyperbranched glycidol polymer. This was expected to increase the homogeneity of the branching level and suppress interactions with proteins. As a result, composite nanodiamonds with reduced hydrodynamic diameters that are maintained in physiological environments were anticipated. Surfaces of 140-nm-sized nanodiamonds were functionalized with oxygen and carboxyl groups for grafting of hyperbranched dendritic polyglycerol via anionic ring-opening polymerization of glycidol. The modification was verified with Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Dynamic light scattering investigated colloidal stability in pH-diverse (2–12) solutions, concentrated phosphate-buffered saline, and cell culture media. Thermogravimetric analysis of nanodiamonds-protein incubations examined non-specific binding. Fluorescence emission was tested across pH conditions. Molecular dynamics simulations modeled interparticle interactions in ionic solutions. The hyperbranched polyglycerol grafting increased colloidal stability of nanodiamonds across diverse pH, high ionic media like 10 × concentrated phosphate-buffered saline, and physiological media like serum and cell culture medium. The hyperbranched polyglycerol suppressed non-specific protein adsorption while maintaining intensive fluorescence of nanodiamonds regardless of pH. Molecular modelling indicated reduced interparticle interactions in ionic solutions correlating with the improved colloidal stability.

Low-temperature plasma-treated polyethylene oxide for hemostasis and skin wound healing

The development of a hemostatic material capable of controlling substantial blood loss in wound healing scenarios remains a critical challenge in clinical practice. Herein, we treated polyethylene oxide (PEO) with low-temperature plasma irradiation (LTPI) technology in the air, and the modified PEO (CAPEO) was obtained with carboxyl (–COOH) and amine (–NH2) groups. Notably, CAPEO exhibited excellent hydrophilicity, great cytocompatibility, and blood compatibility. Platelets could be activated more and clotting time could be shorter with the treatment of CAPEO than with PEO. More importantly, in the rat liver hemorrhage model, the blood loss in CAPEO (95.8 mg) was less than in PEO (144.2 mg). Moreover, in vivo investigation of skin wound repair, CAPEO could promote epidermal regeneration and collagen deposition, thereby accelerating wound healing. These findings disclose that CAPEO holds great potential for hemostasis and wound healing.

Highly Efficient Nitrogen Reduction to Ammonia through the Cooperation of Plasma and Porous Metal-Organic Framework Reactors with Confined Water.

While the ambient N2 reduction to ammonia (NH3) using H2O as hydrogen source (2N2+6H2O=4NH3+3O2) is known as a promising alternative to the Haber-Bosch process, the high bond energy of N≡N bond leads to the extremely low NH3 yield. Herein, we report a highly efficient catalytic system for ammonia synthesis using the low-temperature dielectric barrier discharge plasma to activate inert N2 molecules into the excited nitrogen species, which can efficiently react with the confined and concentrated H2O molecules in porous metal-organic framework (MOF) reactors with V3+, Cr3+, Mn3+, Fe3+, Co2+, Ni2+ and Cu2+ ions. Specially, the Fe-based catalyst MIL-100(Fe) causes a superhigh NH3 yield of 22.4 mmol g-1 h-1. The investigation of catalytic performance and systematic characterizations of MIL-100(Fe) during the plasma-driven catalytic reaction unveils that the in situ generated defective Fe-O clusters are the highly active sites and NH3 molecules indeed form inside the MIL-100(Fe) reactor. The theoretical calculation reveals that the porous MOF catalysts have different adsorption capacity for nitrogen species on different catalytic metal sites, where the optimal MIL-100(Fe) has the lowest energy barrier for the rate-limiting *NNH formation step, significantly enhancing efficiency of nitrogen fixation.

Influence of energy transfer processes on the rovibrational characteristics of CO2 in low-temperature conversion plasma with Ar and He admixture.

The influence of argon and helium on the rovibrational kinetics of carbon dioxide (CO2) and CO in low-temperature conversion plasma is investigated. With this objective, a combined experimental and computational study is conducted, applying quantum cascade laser infrared absorption spectroscopy to a pulsed DC CO2 glow discharge with varying noble gas admixture and modeling it with a two-term Boltzmann solver. Time-resolved rovibrational temperatures and dissociation fractions are presented, exhibiting an increase in rotational-vibrational non-equilibrium and an increasing CO2 conversion with argon (Ar) and helium (He) admixtures. Results are discussed in the context of energy transfer processes for collisions involving electrons, corroborated by electron-kinetic modeling, and heavy particle collisions. With noble gas addition, an increase in the electron number density, promoting excitation, and the high-energy tail of the electron energy distribution function are found. Penning ionization processes are proposed as an explanation for the increase in conversion, showing higher conversion for Ar due to the lower excitation thresholds and, therefore, larger state population. In the context of rovibrational kinetics, processes leading to the gain or loss of vibrational energy of CO2 are analyzed, pointing out subtle differences in, for example, relaxation rate coefficients between Ar and He. However, the cooling of the gas through conductive heat transfer is identified as the most important influence of the Ar and He admixture, as it keeps the relaxation rate for vibrational quenching low.

Effectiveness of Low-Temperature Plasma Adenoidectomy Combined with Bilateral Tonsillectomy in the Treatment of Snoring in Children and Its Effect on Sleep Quality

Objective: To evaluate the therapeutic effect of low-temperature plasma adenoidectomy (abbreviation: adenoid low-temperature plasma excision) coupled with tonsillectomy (bilateral) on snoring in children. Methods: Seventy-six cases of snoring children treated in the hospital between November 2020 and November 2023 were selected. 38 cases of children in Group A agreed to surgery and were admitted to the hospital for surgical treatment and were treated with adenoid cryo-plasma excision combined with tonsillectomy (bilaterally), and 38 cases of children in Group B did not agree to outpatient conservative treatment for surgery, and the results of the treatment were compared. Results: Before treatment, there was no difference between the ventilation function indexes, sleep quality scores, and quality of life scores of the two groups compared with each other (P &gt; 0.05). After treatment, the ventilation function indexes of Group A were better than Group B, and the sleep quality score and quality of life score were higher than that of Group B. The total effective rate of Group A was higher than that of Group B (P &lt; 0.05). Conclusion: Adenoid cryo-plasma excision combined with tonsillectomy (bilateral) can improve the quality of life, ventilation function, and sleep quality of children with snoring, and can enhance the efficacy.

The impact of atmospheric air plasma treatment on the polyfunctional end-use polyester fabric using new synthetic pyrazole dye

Before gluing, bonding, and painting, a variety of materials' surfaces can be modified using the widely used plasma treatment technique. These materials include plastics, glass, metals, and wood. Materials' physical and chemical properties are changed in an environmentally responsible way to enhance or confer particular qualities. The recently used technology known as low-temperature atmospheric pressure plasma (LTAPP) allows heat-sensitive materials to be surface modified in a simple, one-step process. Polymer-based materials are frequently surface modified using LTAPP treatment to improve adhesion, printability, and surface sterility. Polyester's superior mechanical and physical qualities have led to its widespread use as a technical textile and garment material in the form of fibers, films, and plastics. Its limited versatility in terms of end use has been caused by its poor surface properties as the hydrophobic nature of polyester surface, roughness, the crystallinity, and lack of dyeability which are the main drawback restricting its use in different textile applications especially during wet treatments unlike natural fibers. In order to increase the fabric's hydrophilicity and dyeability, the surface of a polyester fabric was altered in this study using atmospheric pressure plasma treatment with atmospheric plasma jet and dielectric barrier discharge (APJ-DBD) technology in air. The primary obstacles in making dielectric barrier discharge (DBD) plasma treatment suitable for industrial purposes are the extended duration of treatment and the utilization of elevated voltage levels. The combination between the atmospheric plasma jet and the dielectric barrier discharge reduces the optimal treatment time to 1 min and the applied voltage to 3.3 kV. After being exposed to oxygen plasma species for a brief period of time (between 30 and 300 s), and were analyzed using an X-ray diffraction machine, an X-ray photoelectron spectroscopy (XPS), static contact angle, and a scanning electron microscope (SEM) to investigate changes in the morphology and chemical nature of the surface, respectively. Fabric wettability increased as a result of plasma treatment, which also increased the fabric's surface roughness, as demonstrated by SEM and X-ray diffraction. The contact angle decreases by increasing the treatment time. The dyeability of untreated and plasma-treated samples was examined with respect to washing, rubbing, perspiration, sublimation, and light fastness. Additionally, color strength was examined. Adequately, compared to the untreated fabric, polyester treated with plasma showed improved dyeing performances. The technical reactivity of poly (ethylene-terephthalate) (PET) fabrics was found to be effectively increased by atmospheric air plasma treatment, creating new avenues for surface modification in light of the expanding environmental and energy-saving concerns.

Impact of Low-Temperature Plasma Radiofrequency Tonsillectomy on Pain, Inflammatory Markers, and Sleep Quality in Adults with Chronic Tonsillitis.

Chronic tonsillitis (CT) is a very common ear, nose, and throat disease worldwide, and in severe cases it can cause sleep apnea hypoventilation syndrome, which can affect the patient's health and can even be life-threatening. Low-temperature plasma radiofrequency tonsillectomy is one of the commonly used methods for treating CT with remarkable results, but more detailed reports are lacking. In this study, we aimed to explore the impact of low-temperature plasma radiofrequency tonsillectomy on pain, inflammatory markers, and sleep quality in adult CT patients for clinical reference. A retrospective study was performed on adult patients diagnosed with CT at our hospital between June 2019 and October 2023. Patients were categorized into a control group receiving traditional tonsillectomy and a treatment group undergoing low-temperature plasma radiofrequency tonsillectomy. The groups were compared in terms of baseline characteristics, surgical parameters, visual analogue scale (VAS) scores, 36-item short form (SF-36) health survey questionnaire scores, inflammatory markers, and Pittsburgh Sleep Quality Index (PSQI) scores. Group differences in postoperative complications were also analyzed. There were 160 patients, 80 in the treatment group (50 males and 30 females, mean age 28.90 ± 2.46 years) and 80 in the control group (46 males, 34 females, mean age 28.89 ± 2.01 years). Differences between the two groups in terms of age, sex, duration of disease, smoking history, body mass index, and other baseline characteristics were not statistically significant (p > 0.05). Operation time, intraoperative bleeding, return to normal diet, and pseudomembrane detachment time in the treatment group were all significantly lower than in the control group (p < 0.05). There were no significant differences in VAS or SF-36 scores before treatment (p > 0.05). Post-treatment, both groups had lower VAS scores and higher SF-36 scores in the treatment group compared to the control group (p < 0.05). There were no significant differences in levels of inflammatory markers before treatment (p > 0.05). Both groups showed increased levels of inflammatory markers post-treatment, but the treatment group had lower post-treatment levels of Interleukin-6 (IL-6) and hypersensitive-C reactive protein (hs-CRP) than the control group (p < 0.05). No significant difference was observed between the two groups in PSQI scores before treatment (p > 0.05). Following treatment, both groups had decreased PSQI scores, with lower scores in the treatment group than in the control group (p < 0.05). The complication rate was lower in the treatment group than in the control group, with rates of 8.75% and 23.75%, respectively (p < 0.05). Low-temperature plasma radiofrequency tonsillectomy for adult CT patients offers advantages such as shorter surgical time, reduced intraoperative bleeding, minimal trauma, and fewer postoperative complications. This procedure significantly alleviates pain, improves quality of life, reduces levels of inflammatory markers, and enhances sleep quality.

AgIn5S8/g-C3N4 Composite Photocatalyst Coupled with Low-Temperature Plasma-Enhanced Degradation of Hydroxypropyl-Guar-Simulated Oilfield Wastewater.

The effective treatment and recovery of fracturing wastewater has always been one of the difficult problems to be solved in oilfield wastewater treatment. Accordingly, in this paper, photocatalytic-coupled low-temperature plasma technology was used to degrade the simulated wastewater containing hydroxypropyl guar, the main component of fracturing fluid. Results indicated that hydroxypropyl-guar wastewater could be degraded to a certain extent by either photocatalytic technology or plasma technology; the chemical oxygen demand and viscosity of the treated wastewater under two single-technique optimal conditions were 781 mg·L-1, 0.79 mPa·s-1 and 1296 mg·L-1, 1.01 mPa·s-1, respectively. Furthermore, the effective coupling of AgIn5S8/gC3N4 photocatalysis and dielectric-barrier discharge-low-temperature plasma not only enhanced the degradation degree of hydroxypropyl guar but also improved its degradation efficiency. Under the optimal conditions of coupling treatment, the hydroxypropyl-guar wastewater achieved the effect of a single treatment within 6 min, and the chemical oxygen demand and viscosity of the treated wastewater reduced to below 490 mg·L-1 and 0.65 mPa·s-1, respectively. In the process of coupled treatment, the AgIn5S8/gC3N4 could directly absorb the light and strong electric field generated by the system discharge and play an important role in the photocatalytic degradation, thus effectively improving the energy utilization rate of the discharge system and enhancing the degradation efficiency of hydroxypropyl guar.

Polycaprolactone scaffold surface modification with soft X-ray/extreme ultraviolet (SXR/EUV) radiation and low-temperature oxygen and nitrogen plasma for biomedical applications

Modification of the surfaces of polymeric scaffolds is often required to make the material suitable for specific tissue engineering applications. Physico-chemical properties of scaffolds can be altered using various methods, such as plasma treatment, laser processing, chemical modifications, grafting with nanoparticles, or surface coating. In this paper physico-chemical modification of polycaprolactone (PCL) surface fibers was performed by exposing PCL samples to simultaneous soft X-ray/extreme ultraviolet (SXR/EUV) radiation and low-temperature, SXR/EUV-induced, nitrogen, and oxygen plasmas. The physical and chemical changes on modified PCL surfaces were examined using a scanning electron microscope and X-ray photoelectron spectroscopy, respectively. The effects of physico-chemical scaffold surface changes were verified with biological tests, i.e., MTT assay and immunofluorescence on murine osteoblast cell line (7F2). It was found that exposure of scaffolds to ionizing radiation and low-temperature plasmas induced strong chemical changes on their surface, i.e., appearance of various new chemical groups. Also, smoothing of the surface of PCL fibers, i.e., disappearance or significant reduction of the size of micropores on their fibers was also observed. Increased viability and adhesion of 7F2 osteoblasts on modified PCL samples after 24 h cell culture compared to non-treated PCL was also confirmed.Graphical abstract

An experimental study on low-temperature plasma tissue ablation and its thermal effect

Low-temperature plasma ablation has been recently used for minimally invasive surgeries. However, more research is still needed on its generation process during tissue ablation and the underlying mechanism of tissue thermal damage. In this paper, high-speed camera footage, voltage–current signal collection, temperature analysis, and histological analysis were used to investigate the dynamic process of plasma tissue ablation and its thermal effect of dual-needle electrodes immersed in normal saline, which were driven by a high-frequency DC power supply with an output voltage ranging from 220 V to 320 V and a squire wave of 100 kHz. Microbubbles occurred around the ground electrode and merged to form a vapor layer that could completely cover the ground electrode. Plasma capable of ablating tissue would occur in the vapor layer between the ground electrode and tissue. The effect of electrical parameters on plasma generation and its thermal effect are analyzed by statistical results. The experimental results indicated that the voltage applied to the electrodes significantly influenced both the generation and stability of plasma, as well as the heat generation and tissue damage around the electrodes. Furthermore, under the same voltage, the existence of biological tissue promotes the formation of a vapor layer around the electrode, thereby facilitating the generation and stability of plasma. Notably, the temperature rise around the ground electrode is much higher than that around the powered electrode. These results have direct application to the design of plasma tissue ablation systems, which could achieve tissue ablation effects with minimal thermal damage.

Comprehensive analysis and treatment of intraoral thyroglossal duct cysts with intraoperative techniques: a 7-case series review in a tertiary care center

ObjectiveIntraoral thyroglossal duct cyst is a relatively rare clinical disease. This article reviews the diagnosis and treatment process of 7 patients and explores the clinical characteristics of diagnosis and treatment of intraoral thyroglossal duct cyst in combination with past literature reports. MethodA retrospective analysis was conducted on 7 cases of intraoral thyroglossal duct cyst admitted to the Otolaryngology ward of Dalian Municipal Central Hospital from January 2017 to January 2024. The cases were recorded in terms of gender, age, symptoms, physical signs, radiological examinations, surgical methods, and postoperative complications. All cases were followed up, and the latest follow-up results were recorded. ResultsAmong the 7 cases, 6 patients underwent laryngoscopic and radiological examinations before surgery, and 1 child was found to have a cyst during surgery. All cases were diagnosed with intraoral thyroglossal duct cyst and treated with plasma radiofrequency surgery. None of the patients had postoperative complications, and no recurrence was found in the six-month follow-up after discharge. ConclusionIntraoral thyroglossal duct cyst is rare in clinical practice. It is important to pay attention to its differential diagnosis clinically, and careful review of images is required before surgery. Cryoablation with low-temperature plasma radiofrequency is not only minimally invasive and has a quick recovery but also has few complications and a low recurrence rate. It is a safe and effective treatment method that is worthy of clinical promotion. Level of EvidenceLevel 3.