Journal articles: '[SiH4 + CO2 + He] plasma'

1

Samanta, Arup, and Debajyoti Das. "Structural investigation of nC-Si/SiOx:H thin films from He diluted (SiH4+CO2) plasma at low temperature." Applied Surface Science 259 (October 2012): 477–85. http://dx.doi.org/10.1016/j.apsusc.2012.07.070.

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Samanta, Arup, and Debajyoti Das. "Studies on the structural properties of SiO:H films prepared from (SiH4+CO2+He) plasma in RF-PECVD." Solar Energy Materials and Solar Cells 93, no. 5 (May 2009): 588–96. http://dx.doi.org/10.1016/j.solmat.2008.12.005.

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Sobajima, Yasushi, Shota Kinoshita, Shinnosuke Kakimoto, Ryoji Okumoto, Chitose Sada, Akihisa Matsuda, and Hiroaki Okamoto. "Control of growth process for obtaining high-quality a-SiO:H." Canadian Journal of Physics 92, no. 7/8 (July 2014): 582–85. http://dx.doi.org/10.1139/cjp-2013-0558.

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Film-growth process of hydrogenated amorphous silicon–oxygen alloys (a-SiO:H) from CO2/(CO2 + SiH4) plasma has been investigated to control the optoelectronic properties in the resulting materials. Optical emission spectroscopy results and simple simulation results for steady-state density of chemical species in the plasma indicate that main film-growth precursors for a-SiO:H are SiH3, OH, and O. Si dangling-bond defect density is drastically increased in a-SiO:H when increasing the CO2 gas ratio in CO2/(CO2 + SiH4) plasma, being caused by the increase in the contribution ratio of Si-related short-lifetime species (SiHx, x < 2) to film growth owing to a severe SiH4-molecule depletion because of high-rate consumption reaction of SiH4 with O produced from CO2 in the plasma. Considering the primary electron impact dissociation reactions of source gas molecules and several secondary chemical reactions in the plasma, the guiding principle for obtaining high quality a-SiO:H has been proposed.

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Jo, Sanghyun, Suik Kang, Kyungjun Lee, and Ho Jun Kim. "Helium Metastable Distributions and Their Effect on the Uniformity of Hydrogenated Amorphous Silicon Depositions in He/SiH4 Capacitively Coupled Plasmas." Coatings 12, no. 9 (September 15, 2022): 1342. http://dx.doi.org/10.3390/coatings12091342.

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This study investigates, numerically, the spatial distribution of metastable helium (He*) in He/SiH4 capacitively coupled plasma (CCP) for the purpose of optimizing plasma density distributions. As a first step, we presented the results of a two-dimensional fluid model of He discharges, followed by those of He/SiH4 discharges to deposit hydrogenated amorphous silicon films, to investigate which factor dominates the coating uniformity. We retained our CCPs in the 300 mm wafer reactor used by the semiconductor industry in the recent past. Selected parameters, such as a sidewall gap (radial distance between the electrode edge and the sidewall), electrical condition of the sidewall, and position of the powered electrode, were considered. In addition, by increasing the gas pressure while varying the sidewall condition, we observed modification of the plasma distributions and, thus, the deposition rate profiles. According to the results, the shift in He* distributions was mainly due to the reduction in the electron mean free path under conditions of gas pressure higher than 100 Pa, as well as local perturbations in the ambipolar electric field due to the finite electrode structure. Small additions of SiH4 largely changed the He* density profile in the midplane of the discharge due to He* quenching. Furthermore, we found that the wide sidewall gap did not improve deposition uniformity against the expectation. This was because the excitation and ionization rate profiles were enhanced and localized only near the bottom electrode edge.

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Ershov, I. A., V. I. Pustovoy, V. I. Krasovskii, A. N. Orlov, S. I. Rasmagin, L. D. Iskhakova, F. O. Milovich, M. N. Kirichenko, L. L. Chaikov, and E. A. Konstantinova. "Synthesis and properties of silicon carbide nanoparticles obtained by laser pyrolysis method." Physics and Chemistry of Materials Treatment 1 (2021): 51–57. http://dx.doi.org/10.30791/0015-3214-2021-1-51-57.

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The conditions for the synthesis of silicon carbide nanoparticles in a SiH4/C2H2/Ar/He gas mixture under the action of CO2 laser radiation with a wavelength of 10.6 μm are determined. It was found that laser synthesis of SiC particles is observed when the ratio of gas flows SiH4/C2H2 is in the range of 1.6-3.2. The temperature in the region of the reaction zone was ~1400-1500°C. Silicon carbide nanoparticles ~6 nm in diameter were obtained and their composition was investigated.

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Park, Hwanyeol, and Ho Jun Kim. "Theoretical Analysis of Si2H6 Adsorption on Hydrogenated Silicon Surfaces for Fast Deposition Using Intermediate Pressure SiH4 Capacitively Coupled Plasma." Coatings 11, no. 9 (August 29, 2021): 1041. http://dx.doi.org/10.3390/coatings11091041.

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The rapid and uniform growth of hydrogenated silicon (Si:H) films is essential for the manufacturing of future semiconductor devices; therefore, Si:H films are mainly deposited using SiH4-based plasmas. An increase in the pressure of the mixture gas has been demonstrated to increase the deposition rate in the SiH4-based plasmas. The fact that SiH4 more efficiently generates Si2H6 at higher gas pressures requires a theoretical investigation of the reactivity of Si2H6 on various surfaces. Therefore, we conducted first-principles density functional theory (DFT) calculations to understand the surface reactivity of Si2H6 on both hydrogenated (H-covered) Si(001) and Si(111) surfaces. The reactivity of Si2H6 molecules on hydrogenated Si surfaces was more energetically favorable than on clean Si surfaces. We also found that the hydrogenated Si(111) surface is the most efficient surface because the dissociation of Si2H6 on the hydrogenated Si(111) surface are thermodynamically and kinetically more favorable than those on the hydrogenated Si(001) surface. Finally, we simulated the SiH4/He capacitively coupled plasma (CCP) discharges for Si:H films deposition.

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Jia, Haijun, and Michio Kondo. "High rate synthesis of crystalline silicon films from SiH4+He using high density microwave plasma." Journal of Applied Physics 105, no. 10 (May 15, 2009): 104903. http://dx.doi.org/10.1063/1.3129321.

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Das, Debajyoti, Madhusudan Jana, and A. K. Barua. "Characterization of undoped μc-SiO:H films prepared from (SiH4+CO2+H2)-plasma in RF glow discharge." Solar Energy Materials and Solar Cells 63, no. 3 (July 2000): 285–97. http://dx.doi.org/10.1016/s0927-0248(00)00035-0.

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9

Lee, Sung‐Woo, Du‐Chang Heo, Jin‐Kyu Kang, Young‐Bae Park, and Shi‐Woo Rhee. "Microcrystalline Silicon Film Deposition from H 2 ‐ He ‐ SiH4 Using Remote Plasma Enhanced Chemical Vapor Deposition." Journal of The Electrochemical Society 145, no. 8 (August 1, 1998): 2900–2904. http://dx.doi.org/10.1149/1.1838733.

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10

Dian, J., J. Valenta, J. Hála, A. Poruba, P. Horváth, K. Luterová, I. Gregora, and I. Pelant. "Visible photoluminescence in hydrogenated amorphous silicon grown in microwave plasma from SiH4 strongly diluted with He." Journal of Applied Physics 86, no. 3 (August 1999): 1415–19. http://dx.doi.org/10.1063/1.370904.

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11

Sritharathikhun, Jaran, Taweewat Krajangsang, Apichan Moollakorn, Sorapong Inthisang, Amornrat Limmanee, Aswin Hongsingtong, Nattaphong Boriraksantikul, Tianchai Taratiwat, Nirod Akarapanjavit, and Kobsak Sriprapha. "Effect of the CO2/SiH4Ratio in the p-μc-SiO:H Emitter Layer on the Performance of Crystalline Silicon Heterojunction Solar Cells." International Journal of Photoenergy 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/872849.

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This paper reports the preparation of wide gap p-type hydrogenated microcrystalline silicon oxide (p-μc-SiO:H) films using a 40 MHz very high frequency plasma enhanced chemical vapor deposition technique. The reported work focused on the effects of the CO2/SiH4ratio on the properties of p-μc-SiO:H films and the effectiveness of the films as an emitter layer of crystalline silicon heterojunction (c-Si-HJ) solar cells. A p-μc-SiO:H film with a wide optical band gap (E04), 2.1 eV, can be obtained by increasing the CO2/SiH4ratio; however, the tradeoff betweenE04and dark conductivity must be considered. The CO2/SiH4ratio of the p-μc-SiO:H emitter layer also significantly affects the performance of the solar cells. Compared to the cell using p-μc-Si:H (CO2/SiH4= 0), the cell with the p-μc-SiO:H emitter layer performs more efficiently. We have achieved the highest efficiency of 18.3% with an open-circuit voltage (Voc) of 692 mV from the cell using the p-μc-SiO:H layer. The enhancement in theVocand the efficiency of the solar cells verified the potential of the p-μc-SiO:H films for use as the emitter layer in c-Si-HJ solar cells.

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Zhang, Yan, Rui Juan Liu, Zhong Xuan Shang, Yin Ding Lv, and Biao Gu. "The Surface Hydrophilicity of Polypropylene Non-Woven Treated by Atmospheric Glow Plasma." Advanced Materials Research 328-330 (September 2011): 1413–16. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.1413.

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In this paper, polypropylene (PP) melt blown non-woven fabric is treated by atmospheric He, He/O2 or He/CO2 glow discharge plasma. The variation of the surface hidrophilicity of PP sample is experimentally investigated by the surface water contact angle. The results show that the surface water contact angle firstly has a sharp decline and then up to saturation. It is worth noting that the time the water contact angle is up to saturation greatly shortens when a spot of O2 or CO2 are added into the atmospheric He. In addition, when the PP samples are treated by the atmospheric glow discharge plasma, it is necessary of selecting a right applied voltage.

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13

Das, Debajyoti, Debnath Raha, Wei-Chao Chen, Kuei-Hsien Chen, Chien-Ting Wu, and Li-Chyong Chen. "Effect of substrate bias on the promotion of nanocrystalline silicon growth from He-diluted SiH4 plasma at low temperature." Journal of Materials Research 27, no. 9 (February 16, 2012): 1303–13. http://dx.doi.org/10.1557/jmr.2012.4.

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14

Kim, Ho Jun. "Importance of Dielectric Elements for Attaining Process Uniformity in Capacitively Coupled Plasma Deposition Reactors." Coatings 12, no. 4 (March 28, 2022): 457. http://dx.doi.org/10.3390/coatings12040457.

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In this study, the effect of dielectric elements on plasma radial uniformity was analyzed for a 300 mm wafer process in a capacitively coupled plasma deposition reactor. Based on a two-dimensional self-consistent fluid model, numerical simulations were performed for SiH4/He discharges at 1200 Pa and at the radio frequency of 13.56 MHz. Although in current plasma processes the wafer is often coated with non-conducting films and placed on a ceramic substrate, related materials have not been analyzed. Therefore, the plasma characteristics were studied in depth by changing the wafer material from silicon to quartz, the electrode material from aluminum to aluminum nitride, and the sidewall material from quartz to perfect dielectric. It was demonstrated that dielectric elements with a lower dielectric constant modify the spatial distributions of plasma parameters. In spite of the thinness of the wafer, as the dielectric constant of the wafer decreases, the electric field at the wafer edge becomes weaker owing to the stronger surface-charging effect. This gives rise to the relatively lower density of reactive species such as SiH2+, Si+, He*, and SiH3 near the wafer edge. In addition, radially uniform plasma was induced by the perfect dielectric sidewall, regardless of the dielectric constant of the wafer. This modification occurred because the radial positions of the peak values of the plasma parameters were moved away from the wafer edge. Therefore, the uniform distribution of the plasma density could be largely achieved by the optimal combination of dielectric elements.

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15

Das, Debajyoti, Debnath Raha, and Koyel Bhattacharya. "Evolution of nc-Si Network and the Control of Its Growth by He/H2 Plasma Assistance in SiH4 at PECVD." Journal of Nanoscience and Nanotechnology 9, no. 9 (September 1, 2009): 5614–21. http://dx.doi.org/10.1166/jnn.2009.1151.

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16

Sohn, Hong Lae, Young Tae Cho, and Bong Ju Lee. "Measurement of Carboxyl Group Separated from a Thin Film Copolymerized by Low-Temperature Plasma at Atmospheric Pressure of C₂H₂ and CO₂." Key Engineering Materials 321-323 (October 2006): 1332–35. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.1332.

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We developed a device that makes possible the normal generation of low-temperature plasma under atmospheric pressure. For plasma generation, a radio frequency of rf (13.56 MHz) was used, for plasma gas, helium (He), and for material gases, acetylene (C2H2) and toluene (C6H5CH3) were used. As a result of measuring Fourier transform infrared (FT-IR) after adding the CO2 gas to the generated plasma, the absorption of C=O (carboxyl group) was observed around 1715 cm-1. When the flow rates of the added CO2 increased, the absorption peak increased at the same time, and we knew that this originated from the CO2 molecules.

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Wang, Xu-Cheng, Ji-Xin Bai, Tai-Heng Zhang, Ying Sun, and Yuan-Tao Zhang. "Comprehensive study on discharge characteristics in pulsed dielectric barrier discharges with atmospheric He and CO₂." Physics of Plasmas 29, no. 8 (August 2022): 083503. http://dx.doi.org/10.1063/5.0096172.

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The atmospheric pulsed dielectric barrier discharges have been studied extensively for their huge potential in plasma applications. In this paper, a comprehensive study of discharge characteristics in atmospheric He and CO2 discharges driven by pulsed voltages is carried out by experimental measurements and numerical simulation. The computational data indicate that during a plateau phase in the pulsed CO2 discharge, a strong electric field of 2.6 kV/cm always sustains to drive the heavy ions of [Formula: see text] and [Formula: see text] to the surfaces of dielectric material, forming a discharge current density of about 2.5 [Formula: see text]. The experimental measurements and simulation data show that the duration of the plateau phase has a significant influence on the discharge characteristics of pulsed CO2 discharges but only slightly affects on the discharge evolution in pulsed He discharge. By increasing the duration of the plateau phase, the surface charges accumulated on the dielectric materials are also enhanced, and then, a stronger induced electric field is established in the discharge region, resulting in a larger discharge current density during the pulse fall phase, which is not observed in the pulsed He discharge. In this study, the different discharge behaviors of pulsed He and CO2 discharges are compared in detail, which can enhance the understanding of the underpinning discharge physics, suggesting the optimized ways to utilize pulsed discharges with various plasma-forming gases.

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Takahashi, Hidemi, Minoru Kimura, Reiji Sano, Yoshio Nagayama, and Kenro Miyamoto. "Heterodyne interferometer of coaxial CO2 and He–Ne lasers for plasma density measurements." Review of Scientific Instruments 57, no. 7 (July 1986): 1286–89. http://dx.doi.org/10.1063/1.1138644.

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19

Kim, Ho Jun, and Jung Hwan Yoon. "Computational Fluid Dynamics Analysis of Particle Deposition Induced by a Showerhead Electrode in a Capacitively Coupled Plasma Reactor." Coatings 11, no. 8 (August 23, 2021): 1004. http://dx.doi.org/10.3390/coatings11081004.

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Defect formation in the deposition of thin films for semiconductors is not yet sufficiently understood. In a showerhead-type capacitively coupled plasma (CCP) deposition reactor, the showerhead acts as both the gas distributor and the electrode. We used computational fluid dynamics to investigate ways to enhance cleanliness by analyzing the particle deposition induced by the showerhead electrode in a CCP reactor. We analyzed particle transport phenomena using a three-dimensional complex geometry, whereas SiH4/He discharges were simulated in a two-dimensional simplified geometry. The process volume was located between the RF-powered showerhead and the grounded heater. We demonstrated that the efficient transportation of particles with a radius exceeding 1 μm onto the heater is facilitated by acceleration inside the showerhead holes. Because the available space in which to flow inside the showerhead is constricted, high gas velocities within the showerhead holes can accelerate particles and lead to inertia-enhanced particle deposition. The effect of the electrode spacing on the deposition of particles generated in plasma discharges was also investigated. Smaller electrode spacing promoted the deposition of particles fed from the showerhead on the heater, whereas larger electrode spacing facilitated the deposition of particles generated in plasma discharges on the heater.

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20

Santato, Clara, Giorgio Mattei, Wu Ruihua, and Federico Mecarini. "In situmicro Raman investigation of the laser crystallization in Si thin films plasma enhanced chemical vapor deposition-grown from He-diluted SiH4." Journal of Applied Physics 95, no. 10 (May 15, 2004): 5366–72. http://dx.doi.org/10.1063/1.1699506.

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Kim, Ho Jun. "Enhancement of Cleanliness and Deposition Rate by Understanding the Multiple Roles of the Showerhead Electrode in a Capacitively Coupled Plasma Reactor." Coatings 11, no. 8 (August 21, 2021): 999. http://dx.doi.org/10.3390/coatings11080999.

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Increasing the productivity of a showerhead-type capacitively coupled plasma (CCP) reactor requires an in-depth understanding of various physical phenomena related to the showerhead, which is not only responsible for gas distribution, but also acts as the electrode. Thus, we investigated how to enhance the cleanliness and deposition rate by studying the multiple roles of the showerhead electrode in a CCP reactor. We analyzed the gas transport in a three-dimensional complex geometry, and the SiH4/He discharges were simulated in a two-dimensional simplified geometry. The process volume was installed between the showerhead electrode (radio frequency powered) and the heater electrode (grounded). Our aim of research was to determine the extent to which the heated showerhead contributed to increasing the deposition rate and to reducing the size of the large particles generated during processing. The temperature of the showerhead was increased to experimentally measure the number of particles transported onto the heater to demonstrate the effects thereof on the decrease in contamination. The number of particles larger than 45 nm decreased by approximately 93% when the showerhead temperature increased from 373 to 553 K.

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22

Kim, Ho Jun, and Hae June Lee. "Analysis of intermediate pressure SiH4/He capacitively coupled plasma for deposition of an amorphous hydrogenated silicon film in consideration of thermal diffusion effects." Plasma Sources Science and Technology 26, no. 8 (July 17, 2017): 085003. http://dx.doi.org/10.1088/1361-6595/aa78b4.

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23

Willems, Gert, Ante Hecimovic, Kerstin Sgonina, Emile Carbone, and Jan Benedikt. "Mass spectrometry of neutrals and positive ions in He/CO2 non-equilibrium atmospheric plasma jet." Plasma Physics and Controlled Fusion 62, no. 3 (February 10, 2020): 034005. http://dx.doi.org/10.1088/1361-6587/ab6b4c.

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Jantarang, Salina, Simone Ligori, Jonathan Horlyck, Emma C. Lovell, Tze Hao Tan, Bingqiao Xie, Rose Amal, and Jason Scott. "Plasma-Induced Catalyst Support Defects for the Photothermal Methanation of Carbon Dioxide." Materials 14, no. 15 (July 28, 2021): 4195. http://dx.doi.org/10.3390/ma14154195.

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The presence of defects in a catalyst support is known to benefit catalytic activity. In this work, a He-plasma treatment-based strategy for introducing and stabilising defects on a Ni/TiO2 catalyst for photothermal CO2 hydrogenation was established. The impact of pretreatment step sequence—which comprised He-plasma treatment and reduction/passivation—on defect generation and stabilisation within the support was evaluated. Characterisation of the Ni/TiO2 catalysts indicated that defects created in the TiO2 support during the initial plasma treatment stage were then stabilised by the reduction/passivation process, (P-R)Ni/TiO2. Conversely, performing reduction/passivation first, (R-P)Ni/TiO2, invoked a resistance to subsequent defect formation upon plasma treatment and consequently, poorer photothermal catalytic activity. The plasma treatment altered the metal-support interaction and ease of catalyst reduction. Under photothermal conditions, (P-R)Ni/TiO2 reached the highest methane production in 75 min, while (R-P)Ni/TiO2 required 165 min. Decoupling the impacts of light and heat indicated thermal dominance of the reaction with CO2 conversion observed from 200 °C onwards. Methane was the primary product with carbon monoxide detected at 350 °C (~2%) and 400 °C (~5%). Overall, the findings demonstrate the importance of pretreatment step sequence when utilising plasma treatment to generate active defect sites in a catalyst support.

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Murata, Tatsunori, Yoshihiro Miyagawa, Masazumi Matsuura, Koyu Asai, and Hiroshi Miyatake. "Effect of N2Gas Flow Ratio in Plasma-Enhanced Chemical Vapor Deposition with SiH4–NH3–N2–He Gas Mixture on Stress Relaxation of Silicon Nitride." Japanese Journal of Applied Physics 49, no. 8 (August 20, 2010): 08JF08. http://dx.doi.org/10.1143/jjap.49.08jf08.

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Mijatović, Z., R. Kobilarov, S. Djurović, and M. Stevanov. "Use of He(I) 447.1-nm Line with Forbidden Component for Electron Density Determination in Plasmas." Applied Spectroscopy 51, no. 3 (March 1997): 396–400. http://dx.doi.org/10.1366/0003702981940269.

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Four parameters of the He(I) 447.1-nm line with a forbidden component were measured. A pulsed arc was used as a plasma source. Electron density in the range (1.9–5.9) 1021 m−3 was measured with a CO2 laser interferometer. On the basis of the comparisons of the obtained results with several theories and empirical formulae for plasma density determination, it is shown that this line could be used for simple but precise electron density measurement, with an error < 10%.

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Khumaeni, Ali, Wahyu S. Budi, Asep Y. Wardaya, Hideaki Niki, Kazuyoshi Kurihara, and Kiichiro Kagawa. "Emission Characteristics of Hydrogen and Carbon in Various Ambient Gases using Pulsed-CO2 Laser-Induced Breakdown Spectroscopy." Current Analytical Chemistry 16, no. 3 (May 15, 2020): 234–40. http://dx.doi.org/10.2174/1573411014666181115121139.

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Background: Hydrogen (H) and Carbon (C) are major elements that occur in various materials, including organic matter. The identification and analysis of C and H are necessary for several fields. LIBS is an excellent method for such analysis because it is rapid, and can be conducted remotely. The technique has been employed for the analysis of H in zircaloy metals. However, few studies on the emission characteristics of H and C in various gases have been undertaken because of the difficulty of identifying H and C using standard LIBS techniques. In this work, the emission characteristics of H and C were studied using pulsed CO2 LIBS. H and C elements were obtained from ethanol vapor. Various gas environments were employed, including Nitrogen (N2), Argon (Ar), and Helium (He) gases, in order to study the stability of the laser-induced plasma, the plasma lifetime, and the excitation mechanisms of H and C. Methods: The LIBS system used in this work consisted of a pulsed TEA CO2 laser (Shibuya SQ 2000), pulse generator, and optical multichannel analyzer. In this work, the laser with a wavelength of 10.6 µm, pulse duration of 200 ns, and pulse energy of 3 J, was used as the irradiation source. The laser energy used was 1.5 J. The laser was irradiated, and focused, using a 200 mm zinc selenide (ZnSe) lens, onto a metal surface in order to initiate and induce a luminous plasma. The sample used in this study was ethanol vapor, obtained from ethanol (99.5%, Merck). For this purpose, 10 mL ethanol was poured into a glass beaker, and this was placed into a closed chamber that could be evacuated by ambient gases including N2, Ar, and He gases. Results: Identification of H emission line has been successfully carried out using this present technique demonstrated in various gases including N2, Ar, and He. From the results, it was observed that in N2 gas, the Hα I 656.3 nm emission line was clearly expressed, with a wide, full-width halfmaximum, and quite a low emission intensity. Conclusion: The emission characteristics of H and C in laser-induced plasma, produced in various ambient gases, including N2, Ar, and He, were studied. The emission spectra of Hα and Hβ were expressed clearly, with high intensity and low background emission, in He, while they were broad and had high background emissions in N2 and Ar. Based on the time-resolved emissions, the Hα emission had a longer lifetime in Ar and He. It was assumed that the metastable atoms of Arand He were predominant in the excitation process of H and C. The characteristics of the H and C emissions in various gases are important in selecting a suitable ambient gas for the study of light atomic emission in the medical field, which mostly deals with organic materials containing H, C, and oxygen.

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Wu, Qiang, Lan Ying Xu, and Yong Mao. "Melted Characteristics Effects of Shielding Gas on Laser Deep Penetration Welding." Key Engineering Materials 620 (August 2014): 116–21. http://dx.doi.org/10.4028/www.scientific.net/kem.620.116.

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Adopting coaxial and side blown protective gas to control plasma, many experiments of CO2 laser deep penetration welding on the stainless steel are finished. Considering the protective gas effect of melten characteristics on laser welding,the experiments choose the gas species and composition to promote the collision and energy exchange of gas and plasma; The laminar flow state is holded by controlling the gas runoff, the angle and direction, increaseing the gas stiffness to prevent plasma punctured, and the plasma energy exchange range is close on the surface of the workpiece so that the energy of laser beam is less absorbed by plasma than the workpiece.The experiments indicate that shielding gas suppression are adverse factors on plasma to use alone Ar, He and N2. Adopting He-Ar-N2 and the ratio of 7:4:l as a protective gas when gas flow rate is about 30L/min, the deep and wide ratio is large,the deep penetration welding seam surfaces obtained are smooth,the defects aren't obvious;the protective effect is poor if the gas flow is too large or too small.

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Ramli, Muliadi, Nasrullah Idris, Kenichi Fukumoto, Hideaki Niki, Fujio Sakan, Tadashi Maruyama, Koo Hendrik Kurniawan, Tjung Jie Lie, and Kiichiro Kagawa. "Hydrogen analysis in solid samples by utilizing He metastable atoms induced by TEA CO2 laser plasma in He gas at 1 atm." Spectrochimica Acta Part B: Atomic Spectroscopy 62, no. 12 (December 2007): 1379–89. http://dx.doi.org/10.1016/j.sab.2007.10.007.

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Camacho, J. J., L. Díaz, M. Santos, and J. M. L. Poyato. "Time-resolved optical emission spectroscopic measurements of He plasma induced by a high-power CO2 pulsed laser." Spectrochimica Acta Part B: Atomic Spectroscopy 66, no. 1 (January 2011): 57–66. http://dx.doi.org/10.1016/j.sab.2010.12.001.

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31

Lie, Zener Sukra, Ali Khumaeni, Tadashi Maruyama, Ken-ichi Fukumoto, Hideaki Niki, and Kiichiro Kagawa. "Hydrogen analysis in metal samples by selective detection method utilizing TEA CO2 laser-induced He gas plasma." Applied Physics A 101, no. 3 (July 21, 2010): 555–58. http://dx.doi.org/10.1007/s00339-010-5897-4.

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Sun, Dawei, Yan Cai, Yonggui Wang, Yue Wu, and Yixiong Wu. "Effect of He–Ar ratio of side assisting gas on plasma 3D formation during CO2 laser welding." Optics and Lasers in Engineering 56 (May 2014): 41–49. http://dx.doi.org/10.1016/j.optlaseng.2013.12.009.

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Ducatte, Gerald R., and Gary L. Long. "Effect of Carbon Dioxide and Hydrogen on Nonmetal Emission Intensities in a Helium Microwave-Induced Plasma." Applied Spectroscopy 48, no. 4 (April 1994): 493–501. http://dx.doi.org/10.1366/000370294775268866.

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The effect of the introduction of carbon dioxide and hydrogen on nonmetal atomic and ionic line intensities in a helium microwave-induced plasma is discussed. The addition of these gases is found to diminish the excitation properties of the 150-W He plasma. While the plasma excitation temperature, ionization temperature, and electron number density are not significantly affected by the introduction of these gases, decreases in the emission intensities of atomic and ionic analyte transitions of S, P, Cl, Br, and I are noted with the higher-energy ionic transitions being more greatly affected. A correlation between the energy of the excited state and the depressing effect of CO2 is found by examining the signals of atomic and ionic transitions of Cl. The greater signal depression of the higher-energy nonmetal transitions is found to be consistent with charge transfer theory. These findings emphasize the importance of analyte line selection when a He plasma is being employed for the purpose of element-specific detection of nonmetals in supercritical fluid chromatography.

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de Morais Gouvêa Lima, Gabriela, Celina Faig Lima Carta, Aline Chiodi Borges, Thalita Mayumi Castaldelli Nishime, Cézar Augusto Villela da Silva, Marcelo Vidigal Caliari, Marcia Pinto Alves Mayer, Konstantin Georgiev Kostov, and Cristiane Yumi Koga-Ito. "Cold Atmospheric Pressure Plasma Is Effective against P. gingivalis (HW24D-1) Mature Biofilms and Non-Genotoxic to Oral Cells." Applied Sciences 12, no. 14 (July 19, 2022): 7247. http://dx.doi.org/10.3390/app12147247.

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The effects of helium cold atmospheric pressure plasma (He-CAPP) jet on Porphyromonas gingivalis (HW24D-1) biofilm, on human gingival fibroblasts (HGF) and human gingival keratinocytes (OBA-9) were assessed. Standardized suspension of P. gingivalis was obtained, and biofilms were grown anaerobically for 48 h. After exposition to He-CAPP, the biofilm viability was evaluated by XTT assay. HGF were grown at 37 °C, in an CO2 chamber in DMEM, while OBA-9 cells were cultured in keratinocyte serum-free medium. After 24 h, plates were exposed to He-CAPP for 1 to 7 min. Plasma was generated using a commercial AC power supply with amplitude modulated signal (voltage amplitude of 20 kVp-p, frequency of 31.0 kHz and duty cycle of 22%). The corresponding discharge power was 0.6W at He flow rate of 1 L/min. DNA damage was accessed by static cytometry. Data were analyzed by GraphPad Prism (p < 0.05). Significant reductions in P. gingivalis viability in relation to non-treated groups were detected (p < 0.0001), directly proportional to exposure time. Treated groups were slightly aneuploid after 5- and 7-min treatment in HGF, and for 3 min in OBA-9 cells, with 1.2 DNA index mean. Helium cold atmospheric pressure plasma jet showed inhibitory effect on P. gingivalis mature biofilm and was not genotoxic for epithelial gingival cells and human oral fibroblasts.

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Hossack, A. C., K. D. Morgan, C. J. Hansen, and D. A. Sutherland. "A multi-chord, two-color interferometer using Hilbert transform phase detection for measuring electron density in spheromak plasmas." Review of Scientific Instruments 93, no. 9 (September 1, 2022): 093501. http://dx.doi.org/10.1063/5.0097459.

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A new, four-chord, CO2/He–Ne heterodyne interferometer has been designed and built for measuring line-averaged plasma density in the HIT-SI3 and subsequent HIT-SIU sustained spheromak devices. The two-color system successfully eliminates vibration-induced errors caused by mirrors that are secured to the vacuum chamber and is able to resolve electron densities n e in the full operating range of 1018–1020 m−3 in both experiments with an integrated error of 4.7 × 1017 m−2. Data are presented from high toroidal current plasma discharges, showing the time evolution of electron densities n e and j ϕ/ n e along multiple chords.

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Tyczkowski, Jacek, Hanna Kierzkowska-Pawlak, Jan Sielski, and Iwona Krawczyk-Kłys. "Low-Temperature Plasma Modification of Styrene–Butadiene Block Copolymer Surfaces for Improved Adhesion—A Kinetic Approach." Polymers 12, no. 4 (April 17, 2020): 935. http://dx.doi.org/10.3390/polym12040935.

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This paper proposed a kinetic model that can describe the changes in the adhesion properties of styrene–butadiene (SBS) block copolymer surfaces under the influence of low-temperature plasma treatment. As a measure of these changes, the peel strength of joints formed between the copolymer surface and the polyurethane adhesive was chosen. Five types of low-temperature low-pressure RF plasma, two inert plasmas (Ar and He), and three reactive plasmas (O2, CO2, and CCl4) were tested. It was found that for all these types of plasma, the peel strength with the plasma treatment time first increases rapidly reaching a maximum value, and then there is a visible decrease in peel strength, after which the peel strength increases again. This dependence of the peel strength on the plasma treatment time is very well described by the proposed model, which considers three processes: (1) the generation of radical states followed by the creation of functional groups involved in the adhesive bonding process, (2) the surface cross-linking that decreases the concentration of these functional groups, and (3) the formation of nano-roughness. The model analysis revealed differences between the action of reactive and inert plasmas in the SBS surface cross-linking mechanism and preferential etching process, as well as differences in the generation of radical states between the O2 plasma (electron process) and other plasmas tested (ionic processes).

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MAGUNOV, A. I., A. YA FAENOV, I. YU SKOBELEV, T. A. PIKUZ, S. DOBOSZ, M. SCHMIDT, M. PERDRIX, et al. "X-ray spectra of fast ions generated from clusters by ultrashort laser pulses." Laser and Particle Beams 21, no. 1 (January 2003): 73–79. http://dx.doi.org/10.1017/s0263034603211149.

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The high precision X-ray spectroscopy studies of plasma created from the CO2 clusters in gas jet targets by the ultrashort laser pulses (35 and 60 fs duration) were performed at the intensities IL ∼ 1017–1018 W cm−2. The spectral line shape of the H-like and He-like oxygen ions gains an asymmetry with increasing the laser pulse intensity. Theoretical modeling of the line shape shows that the asymmetry can be explained by absorption of the Doppler-shifted line radiation from the essential fraction of ions (over 10−3) with energies above 1 MeV due to photoionization of inner shells of carbon ions. The results obtained demonstrate measurement capabilities of the X-ray spectral measurements of multicharged ions accelerated during the interaction with a laser radiation.

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Dawei, Sun, Cai Yan, Wu Yue, Zhu Junjie, and Wu Yixiong. "Investigation into the effect of Ar ratio in He-Ar mixture side assisting gas on plasma properties during CO2 laser welding based on 3D reconstruction." Journal of Laser Applications 27, no. 1 (February 2015): 012001. http://dx.doi.org/10.2351/1.4898015.

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Khumaeni, Ali, Zener Sukra Lie, Hideaki Niki, Ken-ichi Fukumoto, Tadashi Maruyama, and Kiichiro Kagawa. "A novel double-pulse laser plasma spectroscopic technique for H analysis in metal samples utilizing transversely excited atmospheric-pressure CO2 laser-induced metastable He atoms." Optical Review 17, no. 3 (May 2010): 285–89. http://dx.doi.org/10.1007/s10043-010-0050-3.

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Sun, Jintao, Qi Chen, Baoming Zhao, Caohui Guo, Jianyu Liu, Mingming Zhang, and Decai Li. "Temperature-dependent ion chemistry in nanosecond discharge plasma-assisted CH₄ oxidation." Journal of Physics D: Applied Physics 55, no. 13 (January 4, 2022): 135203. http://dx.doi.org/10.1088/1361-6463/ac45ac.

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Abstract Ion chemistry with temperature evolution in weakly ionized plasma is important in plasma-assisted combustion and plasma-assisted catalysis, fuel reforming, and material synthesis due to its contribution to plasma generation and state transition. In this study, the kinetic roles of ionic reactions in nanosecond discharge (NSD) plasma-assisted temperature-dependent decomposition and oxidation of methane are investigated by integrated studies of experimental measurements and mathematical simulations. A detailed plasma chemistry mechanism governing the decomposition and oxidation processes in a He/CH4/O2 combustible mixture is proposed and studied by including a set of electron impact reactions, reactions involving excited species, and ionic reactions. A zero-dimensional model incorporating the plasma kinetics solver ZDPlasKin and the combustion chemical kinetics solver CHEMKIN is used to calculate the time and temperature evolution of the ion density. Uncertainty analysis of ionic reactions on key species generation is conducted by using different referenced data, and insignificant sensitivity is found. The numerical model is consistent with experimental data for methane consumption and generation of major species including CO, CO2, and H2. By modeling the temporal evolution of key ions, it is observed that O2 + presents the largest concentration in the discharge stage, followed by CH4 +, CH3 +, and CH2 +, which is in accordance with the traditional ion chemistry in hydrocarbon flames and agrees well with molecular-beam mass spectrometer investigations. The path flux shows that the concentrations of key species, including electrons, O, OH, H, O(1D), O2(a1Δg), O2 +, CH3 +, and CH4 +, change within 1–2 orders of magnitude and that the transition from a homogeneous state to a contracted/constricted state does not occur. The path flux and sensitivity analysis reveal the significant roles of cations in the stimulation of active radical generation, including CH, O, OH, and O(1D), thus accelerating methane oxidation. This work provides a deep insight into the ion chemistry of temperature-dependent plasma-assisted CH4 oxidation.

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Phan, Van, Quan Nguyen, Vien Phan, Feyza Erenler, and Anastassios Pittas. "LBSUN292 Learning Lesson From A Case of Fulminant Type 1 Diabetes Mellitus Shortly After Pembrolizumab Treatment." Journal of the Endocrine Society 6, Supplement_1 (November 1, 2022): A291. http://dx.doi.org/10.1210/jendso/bvac150.600.

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Abstract Background Immune checkpoint inhibitors (ICIs) in cancer treatment are considered one of the major breakthroughs in the past decade. Pembrolizumab (PBL) is one of the immune checkpoint inhibitors that targets the programmed cell death protein-1 (PD-1) receptor in order to block its interaction with programmed cell death ligand-1 (PD-L1) and programmed cell death ligand-2 (PD-L2). By inhibition of these molecules, PBL helps increase T-cell activation against cancer cells. Unfortunately, this inhibition also enhances autoimmunity against normal cells, leading to immune-related adverse events (irAEs) including endocrinopathies. Unlike other irAEs, endocrinopathies are usually irreversible upon diagnosis. While hypophysitis, hypo/hyperthyroidism, and adrenal insufficiency are more commonly reported, type 1 diabetes mellitus (T1DM) is also seen around 0.9 to 1.9% of cases. Unfortunately, it can become fatal if not being promptly recognized. To raise awareness about this life-threatening adverse event, we are reporting a case of new onset T1DM, presenting with diabetic ketoacidosis (DKA) only after 22 days of the first PBL infusion. Clinical case A 19-year-old male was recently diagnosed with NUT (nuclear protein in testis) carcinoma of the left floor of mouth with high PD-L1 score. NUT carcinoma is a rare type of squamous cell cancer with chromosomal rearrangement in the nuclear protein in testis gene (NUTM1) that makes the cancer aggressive and resistant to standard therapy, hence requiring a multimodal approach. This patient underwent surgery followed by concurrent cisplatin-radiation and PBL. Two weeks after his first PBL infusion, he suddenly developed polydipsia, polyuria, and nausea. He continued to receive the second PBL dose on day 20 and developed DKA on day 21. His work-up revealed a plasma glucose of 856 mg/dL, anion gap of 20 (H), CO2 of 17 mEq/L (L), and beta-hydroxybutyrate of 3.35 mmol/L (H), while hemoglobin A1C of only 5.5% suggesting his fulminant progression. He was immediately treated with DKA protocol with clinical improvement. The patient was discharged on basal bolus insulin regimen. He had non-detectable C-peptide (<0.10 ng/mL) and high GAD Antibody (>250 IU/mL) levels, which was consistent with PBL induced T1DM. Conclusion PBL use has been linked to multiple endocrinopathies and even though rare, DKA can also be seen in setting of T-cell mediated irreversible damage to pancreas beta cells. Due to life threatening potential of DKA, clinicians should monitor patients receiving immune checkpoint inhibitors closely and should be aware symptoms of hyperglycemia for earlier intervention. | Keywords: pembrolizumab, NUT carcinoma, diabetic ketoacidosis Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

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Trinh, Ngo Binh, Giang Huong Tran, and Hoang Trung Hieu. "Penile porokeratosis mimicking annular lichen planus." Our Dermatology Online 13, no. 1 (January 3, 2022): 109–10. http://dx.doi.org/10.7241/ourd.20221.30.

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Sir, Porokeratosis is a group of cutaneous diseases presented by epidermal keratinization [1]. Herein, we report the case of a patient with porokeratosis who responded well to carbon dioxide (CO2) laser therapy. A 22-year-old Vietnamese male visited our department with an asymptomatic plaque on the penis present for three months. He denied a family history of similar lesions. A cutaneous examination of the penis revealed an annular, well-circumscribed plaque with slightly raised borders with scales (Fig. 1a). Other mucocutaneous lesions were absent. Fungal microscopy, a rapid plasma reagin (RPR) test, and a Treponema pallidum hemagglutination (TPHA) test were negative. Histological findings revealed a hyperkeratotic lesion with a discrete parakeratotic column. There was the presence of a cornoid lamella, which was a parakeratotic column overlying a small vertical zone of dyskeratotic and vacuolated cells within the epidermis (Fig. 2a). There was also a focal loss of the granular layer. A mild lymphocytic infiltrate could be seen around an increased number of capillaries in the underlying dermis (Fig. 2b). CO2 laser removal was performed. There was no recurrence after a twelve-month follow-up (Fig. 1b). However, a hypopigmented scar was seen. Porokeratosis is an uncommon disorder of keratinization with clinical variants, such as classical porokeratosis of Mibelli, disseminated superficial actinic porokeratosis, linear porokeratosis, and porokeratosis palmaris et plantaris disseminata [2]. Porokeratosis involving the genital areas and other adjacent sites is rare [2]. Genital porokeratosis was first described by Helfman in 1985 [3]. More than 69 cases have been reported in the literature [1]. The pathophysiology of genital porokeratosis remains unknown. It has been supposed that porokeratosis is linked to repeated minor frictional trauma. A benign lesion may transform into squamous cell carcinoma or basal cell carcinoma [4]. However, no malignant transformation of genital porokeratosis has been noted in the literature. Genital porokeratosis manifests itself clinically as classic or plaque-type porokeratosis of Mibelli [2]. Histological findings revealed a cornoid lamella with the absence of a granular layer and dyskeratotic cells in the upper spinous zone [2]. Our case may mimic some annular lesions, such as secondary syphilis, fungal infection, and annular lichen planus. Because a fungal examination and syphilis serology were negative, we could exclude fungal infection and annular secondary syphilis. The distinctive histology of porokeratosis such as a cornoid lamella with a decreased granular layer may help to differentiate between porokeratosis and annular lichen planus [4]. Numerous therapeutic methods of treatment exist, including surgical excision, CO2 laser, cryotherapy, topical retinoids, 5% 5-fluorouracil, vitamin D3 analogs, imiquimod cream, and 3% diclofenac gel [2,5].

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TakallooBakhtiari, Asieh, Julio Piedra Butina, Sheri A. Gillis Funderburk, and Hari V. Brundavanam. "Euglycemic DKA Associated With SGLT2 Inhibitors." Journal of the Endocrine Society 5, Supplement_1 (May 1, 2021): A382. http://dx.doi.org/10.1210/jendso/bvab048.778.

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Abstract Background: DKA associated with SGLT2 inhibitors also known as Euglycemic DKA (EDKA) is a rare condition characterized by milder degrees of hyperglycemia with a blood glucose level < 200 mg/dl. Unfortunately, this unusual feature can often lead to missed or delayed diagnosis with potential life-threatening outcomes. Clinical Case: The patient is a 53-year-old Caucasian male with PMH of type 2 diabetes mellitus treating with Metformin and Empagliflozin. He presented to the emergency room with shortness of breath, flu-like symptoms, and decreased oral intake for a couple of days. Vital signs at presentation were: Temperature 98.2 °F, pulse rate 108 beats/min, respiratory rate 28 breaths/min, and blood pressure 134/72 mmHg. He was alert but ill-looking, moderately dehydrated with dry mucus membranes. The rest of the physical examination was unremarkable at the time of admission. In the initial blood work, sugar was found to be mildly elevated (163mg/dl), and hemoconcentration besides mild pre-renal acute kidney injury was detected. He was also found infected by the COVID-19 virus without hypoxemia or signs of pneumonia. Arterial blood gases showed metabolic acidosis with an elevated anion gap (PH 7.21, CO2 39.93mmHg, HCO3− 10mEq/L, anion gap 21mEq/L). Urine analysis was positive for ketones and glucose. After ruling out other causes of metabolic acidosis by screening for alcohols, salicylates, acetaminophen, lactic acid, and urine toxicology; the diagnosis of EDKA was made. He was treated with a 3L bolus of IV normal saline and an insulin drip with dextrose solution started as per the protocol based on his glucose levels and promptly admitted to the intensive care unit (ICU). Serial blood tests showed gradual resolution of ketoacidosis and anion gap normalized after 36 hours when insulin drip was stopped and replaced by subcutaneous insulin therapy. Conclusion: SGLT2 inhibitors increase the urinary excretion rate of glucose and subsequent fall in plasma glucose level. Thus, In the absence of exogenous insulin use, increase glucagon release resulting in upregulation of lipolysis and activation of the ketogenesis. Factors such as low oral intake, concurrent infection, and alcohol use can also exacerbate the process. Timely diagnosis of EDKA can be a challenge for physicians unfamiliar with this class of medications, additionally, ketone studies and blood gas analyses are not part of the routine workup for diabetic patients in the emergency department. We recommend all first-line care providers to consider ketosis in ill patients with diabetes and metabolic acidosis, despite the normal or near-normal serum glucose levels. EDKA is mainly a diagnosis of exclusion, but treatment is not different from DKA; correcting dehydration by using intravenous fluids and then, initiating insulin drip along with dextrose-containing solutions, and frequent monitoring of serum anion gap.

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Devine, Alma, and Silvia Bercovici. "PSAT007 Pheochromocytoma Presenting With Small Bowel Obstruction." Journal of the Endocrine Society 6, Supplement_1 (November 1, 2022): A89. http://dx.doi.org/10.1210/jendso/bvac150.183.

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Abstract Background Pheochromocytoma is a rare catecholamine producing tumor arising from the adrenal gland with estimated prevalence of 0.1%-0.6%. Most common signs and symptoms of pheochromocytoma, i.e. headache, palpitations and sweating are non-specific and often mimic other diseases. The association between pheochromocytoma and small bowel obstruction however is rarely recognized. Case 55-year-old Russian male with past medical history of alcohol abuse, smoking and hypertension presented to ER with chest pain, abdominal pain, nausea, vomiting, poor appetite, diarrhea and 20 lbs weight loss for 2-3 months. On presentation, patient was hypertensive with blood pressure of 225/137 mm/Hg and heart rate of 126 beats/minute. He appeared uncomfortable, skin was flushed, and he was noted to be tachycardic with distended abdomen and sluggish bowel sounds. Initial laboratory studies revealed hyperkalemia of 7.8 mmol/L, CO2 13 mmol/L, anion gap 21 mEq/L, acute kidney injury with creatinine 1.34 mg/dL, venous pH 7.18, lactic acid of 5.7 mmol/L. A polymerase chain reaction test for COVID-19 was negative. Alcohol and urine drug screen were negative. Persistent diarrhea, abdominal pain with distention prompted evaluation with abdominal X-ray which showed distended small bowel loops. As part of the hypertensive crisis work up, CT angiogram of the chest, abdomen and pelvis with contrast was done and it demonstrated an enhancing left adrenal mass 4.6×4.5 cm with 35 Hounsfield units on the non-contrast study and 95 Hounsfield units on the venous phase. Evaluation of plasma hormone levels revealed elevated metanephrines >5,000 pg/mL (n 0-88 pg/mL) and normetanephrine >6,000 pg/mL (n 0-137 pg/mL). The 24-h urinary catecholamines were highly elevated with metanephrine >9,000 ug (n 58-276 ug/24hr) and normetanephrine >12,000 ug (n 156-729 ug/24hr). Patient was initially treated with Labetalol infusion with noted improvement in diarrhea. His hospital course was complicated by an acute myocardial infarction with cardiac thrombus. Patient was stabilized with Prazosin and discharged from the hospital. One month later he underwent left laparoscopic adrenalectomy. Gross pathology showed 5.1×4.5×3.8 cm adrenal mass with immunohistochemical staining supporting a diagnosis of pheochromocytoma. Discussion Recognition of clinical features of pheochromocytoma is often challenging but important due to its high morbidity and mortality rates. Small bowel obstruction in association with pheochromocytoma is uncommon. In smaller case series, ileus, megacolon, and bowel infarction was observed in patients with larger adrenal masses, typically >70 grams and catecholamine levels more than 4 times the upper limit of normal. This case highlights the importance of maintaining high index of clinical suspicion in early recognition of the gastrointestinal manifestations of pheochromocytoma and its potentially catastrophic consequences. References (1) Hodin R, Diagnosis, and management of pheochromocytoma. Curr Probl Surg. April 2014 Apr;151-87. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

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Ciesla, M., K. Kwasniak, and B. Kolarz. "AB0050 EVALUATION OF THE ASSOCIATION BETWEEN CIRCULATING NON-CODING RNA CIRC_0005567 AND DISEASE ACTIVITY IN PATIENTS WITH RHEUMATOID ARTHRITIS AND ITS BIOLOGICAL FUNCTION IN THE CELL LINE MODEL." Annals of the Rheumatic Diseases 82, Suppl 1 (May 30, 2023): 1204.1–1204. http://dx.doi.org/10.1136/annrheumdis-2023-eular.3667.

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BackgroundRheumatoid arthritis (RA) is a chronic, autoimmune disease that leads to chronic inflammation of synovial tissue, ultimately causing joint damage, disability and premature mortality. Disease affects about 1% of the global population. Circular RNAs (circRNAs) are non-coding molecules and are generated through back splicing, during which the 5 ‘ and 3′ ends are covalently joined. Consequently, the lack of free ends makes them stable and resistant to exonucleases, and they become more suitable biomarkers compared with linear RNAs such as microRNAs (miRs) or long non-coding RNAs. CircRNAs are still poorly understood molecules in relation to RA pathogenesis.ObjectivesThe aim of the study was to find an association between circ_0005567 plasma levels and disease activity in RA patients and to evaluate its molecular function.MethodsA total of 66 individuals, 39 RA patients, and 27 healthy controls. RA patients were selected based on disease activity and RA patients with high disease activity (DAS28 >5,1) and remission (≤2,6) were included. RNA was extracted from plasma and quantitative real-time PCR was used to analyze concentration of circ_0005567. The SW982 cell line was cultured in Dulbecco’s Modified Eagle’s Medium and supplemented with 10% fetal bovine serum. The cell line was grown at 37 °C, in a humidified atmosphere, with 5% CO2. The circ_0005567 silencing was performed by designed small interfered RNAs (siRNAs). Bioinformatic analysis was applied to select the miRs and mRNAs that may interact with circ_0005567. The expression levels of microRNAs were evaluated, subsequently the expression levels of selected mRNAs were performed. The expression levels of miRs and mRNA were evaluated at three time points: after 24h, 48h, and 72h.ResultsThe expression level for circ_0005567 in RA patients was elevated compared to the control group (mean±SD; 173.6±123.8 vs 108.9±81.03, p=0.017). The molecule also showed significant differences in disease activity. Patients with high disease activity had about 70% higher concentration of circ_0005567 than the control group (186.99 vs 108.9, p=0.015).In the cell line model we found an association between silencing circ_0005567 and elevated miR-194 concentration and elevated concentration of three mRNAs:KPNA1, HBEGF, TLN2.ConclusionThe expression of circ_0005567 was related to genes that are significant for the pathogenesis of RA. For example,HBEGFgene expression in fibroblasts plays a role in the remission of rheumatoid arthritis, andKPNA1was reported as seed gene related to RA. Due to the fact that circRNAs are stable and resistant to degradation, plasma concentration of circRNAs may be a new potential epigenetic markers of RA and disease activity.References[1]Panda AC, Dudekula DB, Abdelmohsen K, Gorospe M. Analysis of Circular RNAs Using the Web Tool CircInteractome. Methods Mol Biol. 2018;1724:43-56.[2]Sabir JSM, El Omri A, Banaganapalli B, et al. Dissecting the Role of NF-κb Protein Family and Its Regulators in Rheumatoid Arthritis Using Weighted Gene Co-Expression Network. Front Genet. 2019;10:1163.[3]Chen N, Fan B, He Z, Yu X, Wang J. Identification of HBEGF+ fibroblasts in the remission of rheumatoid arthritis by integrating single-cell RNA sequencing datasets and bulk RNA sequencing datasets. Arthritis Res Ther. 2022;24(1):215.Acknowledgements:NIL.Disclosure of InterestsNone Declared.

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Gaboury, Damien, Dominique Genna, Jacques Trottier, Maxime Bouchard, Jérôme Augustin, and Kelly Malcolm. "The Perron Gold Deposit, Archean Abitibi Belt, Canada: Exceptionally High-Grade Mineralization Related to Higher Gold-Carrying Capacity of Hydrocarbon-Rich Fluids." Minerals 11, no. 10 (September 29, 2021): 1066. http://dx.doi.org/10.3390/min11101066.

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The Perron deposit, an Archean orogenic gold deposit located in the Abitibi belt, hosts a quartz vein-type gold-bearing zone, known as the high-grade zone (HGZ). The HGZ is vertically continuous along >1.2 km, and is exceptionally rich in visible gold throughout its vertical extent, with grades ranging from 30 to 500 ppm. Various hypotheses were tested to account for that, such as: (1) efficient precipitating mechanisms; (2) gold remobilization; (3) particular fluids; (4) specific gold sources for saturating the fluids; and (5) a different mineralizing temperature. Host rocks recorded peak metamorphism at ~600 °C based on an amphibole geothermometer. Visible gold is associated with sphalerite (<5%) which precipitated at 370 °C, based on the sphalerite GGIMFis geothermometer, during late exhumation of verticalized host rocks. Pyrite chemistry analyzed by LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) is comparable to classical orogenic gold deposits of the Abitibi belt, without indication of a possible magmatic fluid and gold contribution. Comparison of pyrite trace element signatures for identifying a potential gold source was inconclusive to demonstrate that primary base-metal rich volcanogenic gold mineralization, dispersed in the host rhyolitic dome, could be the source for the later formation of the HGZ. Rather, nodular pyrites in graphitic shales, sharing similar trace element signatures with pyrite of the HGZ, are considered a potential source. The most striking outcome is the lack of water in the mineralizing fluids, implying that gold was not transported under aqueous complexes, even if fugacity of sulfur (−6) and oxygen (−28), and pH (~7) are providing the best conditions at a temperature of 350 °C for solubilizing gold in water. Fluid inclusions, analyzed by solid-probe mass spectrometry, are rather comparable to fossil gas composed mostly of hydrocarbons (methane and ethane and possibly butane and propane and other unidentified organic compounds), rich in CO2, with N2 and trace of Ar, H2S, and He. It is interpreted that gold and zinc were transported as hydrocarbon-metal complexes or as colloidal gold nanoparticles. The exceptional high content of gold and zinc in the HGZ is thus explained by the higher transporting capacity of these unique mineralizing fluids.

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van den Kerkhof, Alfons M., Graciela M. Sosa, Thomas Oberthür, Frank Melcher, Tobias Fusswinkel, Andreas Kronz, Klaus Simon, and István Dunkl. "The hydrothermal Waterberg platinum deposit, Mookgophong (Naboomspruit), South Africa. Part II: Quartz chemistry, fluid inclusions and geochronology." Mineralogical Magazine 82, no. 3 (April 12, 2018): 751–78. http://dx.doi.org/10.1180/mgm.2018.80.

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AbstractThe historic Waterberg platinum deposit, ~15 km WNW of Mookgophong (formerly Naboomspruit), Limpopo Province, South Africa, is a rare fault-bound hydrothermal vein-type quartz-hematite-platinum-group mineralization. As a continuation of the geochemistry and ore mineralogy studies (Part I, Oberthür et al., 2018), this paper concentrates on the ore-bearing quartz and on the age constraints of ore formation. The state-of-the-art methods used include cathodoluminescence microscopy, electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of trace elements, stable isotope (δ18O) analysis and fluid-inclusion studies. U-Pb and (U-Th)/He radiometric age determination gave ages of 900–1075 Ma suggesting platinum-group element (PGE) mineralization as a result of upwelling fluids with connection to the Bushveld complex during Kibaran tectonic movements along the Thabazimbi–Murchison Lineament. Felsic fragments containing Qtz-1 were cemented by different quartz generations (Qtz-2 to Qtz-4) and enable the characterization of the changing physicochemical parameters during multistage mineralization and cooling. The PGE minerals are associated with the earliest hydrothermal stage represented by botryoidal radial-fibrous quartz aggregates (Qtz-2a) which formed on brecciated felsite. The other quartz types are essentially barren. Cathodoluminescence studies of quartz indicate very high Al, Fe and K concentrations as confirmed by EPMA and LA-ICP-MS, whereas Ti is always very low. The varying Al concentrations in the quartz mainly indicate pH fluctuations, the high Fe3+ points at high oxygen fugacity. Micro-inclusions of iron oxide are associated with Pt ore (Fe, Pt, Pd, Au, W, Sb, As), rutile, kaolinite and muscovite. The hydrothermal activity must have been characterized by low saline (<10 wt%) H2O–NaCl solutions. These fluids mixed with original high-saline NaCl ± CaCl2 ± CO2 brines in the brecciated felsite (Qtz-1). According to the quartz-hematite geothermometer the ore depositional temperatures were ~370–330°C (Qtz-2a), whereas the successive quartz veins formed during cooling towards ~295°C. The transport of PGE must have been facilitated by strongly oxidizing chloride complexes of relatively low salinity and moderate acidity.

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Terekhov, Vladimir A., Evgeny I. Terukov, Yury K. Undalov, Konstantin A. Barkov, Igor E. Zanin, Oleg V. Serbin, and Irina N. Trapeznikova. "Structural Rearrangement of a-SiOx:H Films with Pulse Photon Annealing." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 22, no. 4 (December 15, 2020): 489–95. http://dx.doi.org/10.17308/kcmf.2020.22/3119.

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Amorphous SiOx films with silicon nanoclusters are a new interesting material from the standpoint of the physics, technology, and possible practical applications, since such films can exhibit photoluminescence due to size quantization. Moreover, the optical properties of these structures can be controlled by varying the size and the content of silicon nanoclusters in the SiOx film, as well as by transforming nanoclusters into nanocrystals by means of high-temperature annealing. However, during the annealing of nonstoichiometric silicon oxide, significant changes can occur in the phase composition and the structure of the films. The results of investigations on the crystallization of silicon nanoclusters in a SiOx matrix have shownthat, even a very fast method of annealing using PPA leads to the formation of large silicon crystallites. This also causes the crystallization of at least a part of the oxide phase in the form of silicon hydroxide H6O7Si2. Moreover, in films with an initial content of pure silicon nanoclusters ≤ 50%, during annealing a part of the silicon is spent on the formation of oxide, and part of it is spent on the formation of silicon crystals. While in a film with an initial concentration of silicon nanoclusters ≥ 53%, on the contrary, upon annealing, there occurs a partial transition of silicon from the oxide phase to the growth ofSi crystals Reference 1. Undalov Y. K., Terukov E. I., Silicon nanoclustersncl-Si in a hydrogenated amorphous silicon suboxidematrix a-SiOx:H (0 < x < 2). Semiconductors. 2015;49(7):867- 878. DOI: https://doi.org/10.1134/S10637826150702222. Kim K. H., Johnson E. V., Kazanskii A. G.,Khenkin M. V., Roca P. Unravelling a simple methodfor the low temperature synthesis of siliconnanocrystals and monolithic nanocrystalline thinfilms. Scientific Reports. 2017;7(1) DOI: https://doi.org/10.1038/srep405533. Undalov Y. K., Terukov E. I., Trapeznikova I. N.Formation of ncl-Si in the amorphous matrix a-SiOx-:H located near the anode and on the cathode, usinga time-modulated DC plasma with the (SiH4–Ar–O2)gas phase (Co2 = 21.5 mol%). Semiconductors.2019;53(11): 1514–1523. DOI: https://doi.org/10.1134/S10637826191102284. Terekhov V. A., Terukov E. I., Undalov Y. K.,Parinova E. V., Spirin D. E., Seredin P. V., Minakov D. A.,Domashevskaya E. P. Composition and optical propertiesof amorphous a-SiOx:H films with silicon nanoclusters.Semiconductors. 2016;50(2): 212–216. DOI:https://doi.org/10.1134/S10637826160202515. Terekhov V. A., Turishchev S. Y., Kashkarov V. M.,Domashevskaya E. P., Mikhailov A. N., Tetel’baum D. I.Silicon nanocrystals in SiO2 matrix obtained by ionimplantation under cyclic dose accumulation. PhysicaE: Low-dimensional Systems and Nanostructures.2007;38(1-2): 16–20. DOI: https://doi.org/10.1016/j.physe.2006.12.0306. Terekhov V. A., Turishchev S. Y., Pankov K. N.,Zanin I. E., Domashevskaya E. P., Tetelbaum D. I.,Mikhailov A. N., Belov A. I., Nikolichev D. E., Zubkov S. Y.XANES, USXES and XPS investigations of electronenergy and atomic structure peculiarities of the siliconsuboxide thin film surface layers containing Si nanocrystals.Surface and Interface Analysis. 2010;42(6-7):891–896. DOI: https://doi.org/10.1002/sia.33387. Terekhov V. A., Turishchev S. Y., Pankov K. N.,Zanin I. E., Domashevskaya E. P., Tetelbaum, MikhailovA. N., Belov A. I., Nikolichev D. E. Synchrotron investigationsof electronic and atomic-structure peculiaritiesfor silicon-oxide films’ surface layers containingsilicon nanocrystals. Journal of Surface Investigation.X-ray, Synchrotron and Neutron Techniques. 2011;5(5):958–967. DOI: https://doi.org/10.1134/S102745101110020X8. Sato K., Izumi T., Iwase M., Show Y., Morisaki H.,Yaguchi T., Kamino T. Nucleation and growth of nanocrystallinesilicon studied by TEM, XPS and ESR.Applied Surface Science. 2003;216 (1-4): 376–381. DOI:https://doi.org/10.1016/S0169-4332(03)00445-89. Ledoux G., Gong J., Huisken F., Guillois O., ReynaudC. Photoluminescence of size-separated siliconnanocrystals: Confirmation of quantum confinement.Applied Physics Letters. 2002;80(25): 4834–4836. DOI:https://doi.org/10.1063/1.148530210. Patrone L., Nelson D., Safarov V. I., Sentis M.,Marine W., Giorgio S. Photoluminescence of siliconnanoclusters with reduced size dispersion producedby laser ablation. Journal of Applied Physics. 2000;87(8):3829–3837. DOI: https://doi.org/10.1063/1.37242111. Takeoka S., Fujii M., Hayashi S. Size-dependentphotoluminescence from surface-oxidized Si nanocrystalsin a weak confinement regime. Physical ReviewB. 2000;62(24): 16820–16825. DOI: https://doi.org/10.1103/PhysRevB.62.1682012. Ievlev V. M. Activation of solid-phase processesby radiation of gas-discharge lamps, Russian ChemicalReviews. 2013;82(9): 815–834. DOI: https://doi.org/10.1070/rc2013v082n09abeh00435713. Zimkina T. M., Fomichev V. A. Ultrasoft X-Rayspectroscopy. Leningrad: Leningrad State UniversityPubl.; 1971. 132 p.14. Wiech G., Feldhütter H. O., Šimůnek A. Electronicstructure of amorphous SiOx:H alloy filmsstudied by X-ray emission spectroscopy: Si K, Si L, andO K emission bands. Physical Review B. 1993;47(12):6981–6989. DOI: https://doi.org/10.1103/Phys-RevB.47.698115. Domashevskaya E. P., Peshkov Y. A., TerekhovV. A., Yurakov Y. A., Barkov K. A., Phase compositionof the buried silicon interlayers in the amorph o u s m u l t i l a y e r n a n o s t r u c t u r e s[(Co45Fe45Zr10)/a-Si:H]41 and [(Co45Fe45Zr10)35(Al2O3)65/a-Si:H]41. Surface and Interface Analysis.2018;50(12-13): 1265–1270. DOI: https://doi.org/10.1002/sia.651516. Terekhov V. A., Kashkarov V. M., ManukovskiiE. Yu., Schukarev A. V., Domashevskaya E. P.Determination of the phase composition of surfacelayers of porous silicon by ultrasoft X-ray spectroscopyand X-ray photoelectron spectroscopy techniques.Journal of Electron Spectroscopy and Related Phenomena.2001;114–116: 895–900. DOI: https://doi.org/10.1016/S0368-2048(00)00393-517. JCPDS-International Centre for DiffractionData ICDD PDF-2, (n.d.) card No 01-077-2110.18. JCPDS-International Centre for DiffractionData ICDD PDF-2, (n.d.) card No 00-050-0438.

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Jeung, J.-H., Hak-Gue Lee, Lihong Teng, and W. A. Anderson. "Microwave Plasma CVD of Silicon Nanocrystalline and Amorphous Silicon as a Function of Deposition Conditions." MRS Proceedings 703 (2001). http://dx.doi.org/10.1557/proc-703-v9.25.

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ABSTRACTUsing ECR-CVD (electron cyclotron resonance-chemical vapor deposition), we can make amorphous-silicon (a-Si) and nanocrystalline (nc-Si) thin films. We are looking forward to improve the photo/dark conductivity ratio (σp/σd) by measuring the photo and dark current-voltage (I-V). In the ECR deposition, there are several factors which we can control and adjust for improved results, such as the amounts of silane and argon, the vacuum, and the temperature of the substrate. These become the critical factors for ECR deposition in order to make better films. Input gases consist of Ar, 2%SiH4 in He and H2. In the process, SiH4 is decomposed into SiHx. A residual gas analyzer (RGA) gives composition in the plasma. Because Ar possibly etches the substrate and Si is to be deposited, the best RGA signal is obtained with low Ar content. This work serves to correlate process conditions, RGA signals and electrical data. The best RGA signal occurs for 5 mTorr Ar, 60 mTorr SiH4:He, and power of 600 W. Best value of dark conductivity (σd) was 1.53 × 10-9 S/cm and1.58 × 10-5 S/cm for photo conductivity (σp and low value of σd indicate material with fewer defects. Adding extra H2 improves the photo-conductivity (σp). Applications of these films are heterojunction solar cells and thin film transistors. The heterojunction solar cell had a structure of metal grid/ 500°A of aSi:H/p-Si wafer/Ohmic contact. These cells gave an open circuit voltage (Voc) = 0.51 (V) and short circuit current density (Jsc) = 5.5 mA/cm2 under 50mW/cm2 tungsten halogen lamp. Thin film transistors using nc-Si, with gate length/width (L/W) =450/65 gave field effect mobility of 18 cm2/V-s, and Ion/Ioff of 1.25×105.

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Kang, Su-hyuk, Min-Cheol Lee, Kook-Chul Moon, and Min-koo Han. "The Characteristics of Silicon Dioxide Deposited by Inductively Coupled Plasma Chemical Vapor Deposition at 150°C." MRS Proceedings 769 (2003). http://dx.doi.org/10.1557/proc-769-h6.18.

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AbstractAn ultra-low temperature processed silicon dioxide film has been fabricated by inductively coupled plasma chemical vapor deposition at 150°C using He/N2O/SiH4 mixture. The deposited silicon dioxide film exhibits a high breakdown field larger than 6MV/cm in case of high ICP plasma condition while the flat band voltage of the oxide film significantly shifted in the negative direction with increasing ICP power. In order to obtain both high electrical breakdown filed and the low flat-band voltage, excimer laser irradiation with the energy density of 430mJ/cm2 is employed. The oxide film irradiated by excimer laser exhibited considerably shifted in the positive direction without scarifying the breakdown characteristics.

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Journal articles on the topic '[SiH4 + CO2 + He] plasma'

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