Atmospheric-pressure Plasma Interaction with Thymidine in Aqueous Solution

胸腺嘧啶(THyMInE)是遗传物质的组成成分之一,为了研究等离子体对遗传胸腺嘧啶(THyMInE)的作用过程,利用大气压等离子体对作为遗传物质的胸腺嘧啶(THyMInE)及对应的胸腺嘧啶脱氧核苷(THyMIdInE)进行处理,为了避免空气对遗传物质的影响,采用水中放电装置进行了相关研究。研究结果表明:不同气体等离子体处理后,胸腺嘧啶脱氧核苷会分解为胸腺嘧啶,且氮气等离子体处理时分解速率快于氩气等离子体处理;另外,空气等离子体与氧气等离子体处理后,胸腺嘧啶脱氧核苷会分解产生两种新产物,分别为胸腺嘧啶+OH和胸腺嘧啶脱氧核苷+OH。该研究对了解大气压等离子体对细菌失活的机制具有一定指导作用,同时对等离子体与生物体作用有着积极的指导意义。The cold atmospheric-pressure plasmas have great application prospects in the fields of biomedicine, such as killing virus, sterilization, cancer cells ablation, and surface treatment of organism tissue, etc.Some reports have indicated that the cold atmospheric-pressure plasmas will modify the genetic material(RNA and DNA) in organism tissue.Thymine is one of the components of genetic material.In this paper, in order to study the effect of plasma on genetic Thymine process, Thymine and Thymidine in the aqueous solution were treated by plasma.In order to avoid the effect of air on experiments, a new discharge device was designed to generate large-area plasma in aqueous media.The results show that,after different gas plasma processing, Thymidine decomposes for thymine; After air plasma and oxygen plasma treatment, Thymidine can produce two new decomposition products: Thymine +OH and Thymidine +OH.The study of DNA degration caused by plasma has certain instruction function in biomedicine.福建省自然基金(2014J01025); 国家自然科学基金(11275261)~

铸铁表面液相微弧放电等离子体碳氮共渗研究

采用液相微弧等离子体电解碳氮共渗技术,在乙酰胺甘油水溶液体系下对铸铁进行了碳氮共渗处理。采用扫描电镜观察、XRD物相分析、显微硬度测试、电化学腐蚀分析等方法探讨了不同渗透时间对渗透效果的影响。实验结果表明在700V下处理数分钟即可获得良好的渗透层,处理时间以2min为最佳,如果处理时间过长,则会导致渗透层性能恶化。结果表明,采用液相等离子体电解碳氮共渗技术,在很短时间内就能在基底的表面形成一层由碳铁和氮铁化物组成的碳氮共渗层。处理时间较短时,基底温度较低,渗氮是主要过程。而随着处理时间增加,基底的温度上升,渗碳是主要过程。经过处理的铸铁材料的硬度得到了显著提高,同时也大大改善了其抗腐蚀性能和耐磨性能。广东省自然科学基金,名称:等离子体内含氧自由基对生物样品影响研究,编号:2015A030313005;; 国家自然基金,名称:大气压等离子体诱导癌细胞凋亡的分子机制研究,编号:112752611127526

Balmer Hα, Hβ and Hγ spectral lines intensities in high-power RF hydrogen plasmas

Hα (Balmer-alpha), Hβ (Balmer-beta) and Hγ (Balmer-gamma) spectral line intensities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power (0-6 kW) of ICPs (inductively coupled plasmas). With the increase of net input power, the intensity of H α improves rapidly (0-2 kW), and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes: obvious increase (0-2 kW), rapid increase (2-4 kW), almost constant (4-6 kW); while the intensities of Hγ increase very slowly. The energy levels of the excited hydrogen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results

Effects of atmospheric pressure air plasma pretreatment on the seed germination and early growth of andrographis paniculata

The objective of this paper is to demonstrate whether air plasma can change the seed germination characteristics, seedling emergence, as well as biochemical reactivity, in Andrographis paniculata (A. paniculata) seedlings by modifying the seed coat and finding a beneficial treatment dose. Eight treatment doses and one control were used to conduct electrical conductivity determination, a germination test, a seedling emergence test and a biochemical assay. The results showed that after being treated with air plasma excited at 5950 V for 10 s, the permeability of the seeds was improved significantly, resulting in the acceleration of seed germination and seedling emergence. In the meantime, the catalase activity and catalase isoenzyme expression were also improved, while the malondialdehyde content in the seedlings was decreased (which means greater counteraction with environmental stress). After being treated with 4250 V for 10 s and 5950 V for 20 s, the seed germination was enhanced, but without an obvious change in seedling emergence. However, after treatment with 3400 V for 20 s and 5100 V for 10 s, the permeability of the seeds was decreased, resulting in a delay in seedling emergence. These results indicate that air plasma can change the physiological and biochemical characteristics of Andrographis paniculata seeds by modifying the seed coat, combined with the effects of the active plasma species, and that different treating doses have different effects

Balmer-alpha and Balmer-beta Stark line intensity profiles for high-power hydrogen inductively coupled plasmas

National Magnetic Confinement Fusion Science Program of China [2011GB108011, 2010GB103001]; Major International (Regional) Project Cooperation and Exchanges [11320101005]We compare Balmer-alpha (H-alpha) and Balmer-beta (H-beta) emissions from high-power (1.0-6.0 kW) hydrogen inductively coupled plasmas (ICPs), and propose region I (0.0-2.0 kW), region II (2.0-5.0 kW), and region III (5.0-6.0 kW). In region I, both H a emission intensity (I-alpha) and H-beta emission intensity (I-beta) increase with radio frequency (RF) power, which is explained by the corona model and Boltzmann's law, etc. However, in region II, I-alpha almost remains constant while I-beta rapidly achieves its maximum value. In region III, I a slightly increases with RF power, while I-beta decreases with RF power, which deviates significantly from the theoretical explanation for the H-alpha and H-beta emissions in region I. It is suggested that two strong electric fields are generated in high-power (2.0-6.0 kW) hydrogen ICPs: one is due to the external electric field of high-power RF discharge, and the other one is due to the micro electric field of the ions and electrons around the exited state hydrogen atoms in ICPs. Therefore, the strong Stark effect can play an important role in explaining the experimental results

Generate n-scroll attractor in linear system by scalar output feedback

In this paper we propose a method for designing chaos generators. For a linear system we can design a switching scalar output feedback controller such that the control system exhibits chaotic behavior in form of n-scroll attractor. We present some examples with numerical simulations that illustrate the efficiency of our method. (C) 2003 Elsevier Science Ltd. All rights reserved

Inactivation of Hela cancer cells by an atmospheric pressure cold plasma jet

研究了大气压冷等离子体射流对子宫颈癌HElA细胞的灭活机制.在倒置显微镜下观察不同等离子体处理条件下的细胞形态,并通过中性红吸收测试定量测定各个条件下的细胞存活率.将功率维持在18W,在900Ml/MIn氩等离子体中添入氧气的百分含量分别为1%,2%,4%和8%的条件下处理HElA细胞,探讨活性气体氧气在惰性气体氩气中的百分含量对HElA癌细胞灭活效率的影响,发现添加2%氧气时,氩/氧等离子体灭活效果最佳,处理180S后细胞存活率可降至7%.当继续添加氧超过2%时,灭活效果逐渐减弱,直至8%时,其效果反而不如单纯氩等离子体.通过测量等离子体发射光谱,结果表明活性氧自由基在癌细胞灭活过程中可能起关键作用.An inactivation mechanism study on Hela cancer cells by means of an atmospheric pressure cold plasma jet is presented.Cell morphology is observed under an inverted microscope after plasma treatment.The neutral red uptake assay provides quantitative evaluations of cell viability under different conditions.The effect of the inactivation efficiency of Hela cancer cells in the argon (900 mL/min) with addition of different amount of oxygen (1%, 2%, 4%, 8%) into atmospheric pressure cold plasma jet is discussed under the fixed power 18 W.Results show that 2% O2 addition provides the best inactivation efficiency, and the survival rate can be reduced to 7% after 180 s treatment.When the oxygen addition exceeds 2%, the inactivation efficiency gradually weakens.The effect is not so good as that in pure argon plasma when the oxygen addition arrives at 8%.According to the emission spectrum of the plasmum, it is concluded that the reactive oxygen species in the plasma play a key role in cancer cell inactivation process.国家自然科学基金(批准号:11275261;11005151)资助的课题~

Inactivation of Hela cancer cells by an atmospheric pressure cold plasma jet

研究了大气压冷等离子体射流对子宫颈癌HElA细胞的灭活机制.在倒置显微镜下观察不同等离子体处理条件下的细胞形态,并通过中性红吸收测试定量测定各个条件下的细胞存活率.将功率维持在18W,在900Ml/MIn氩等离子体中添入氧气的百分含量分别为1%,2%,4%和8%的条件下处理HElA细胞,探讨活性气体氧气在惰性气体氩气中的百分含量对HElA癌细胞灭活效率的影响,发现添加2%氧气时,氩/氧等离子体灭活效果最佳,处理180S后细胞存活率可降至7%.当继续添加氧超过2%时,灭活效果逐渐减弱,直至8%时,其效果反而不如单纯氩等离子体.通过测量等离子体发射光谱,结果表明活性氧自由基在癌细胞灭活过程中可能起关键作用.An inactivation mechanism study on Hela cancer cells by means of an atmospheric pressure cold plasma jet is presented.Cell morphology is observed under an inverted microscope after plasma treatment.The neutral red uptake assay provides quantitative evaluations of cell viability under different conditions.The effect of the inactivation efficiency of Hela cancer cells in the argon (900 mL/min) with addition of different amount of oxygen (1%, 2%, 4%, 8%) into atmospheric pressure cold plasma jet is discussed under the fixed power 18 W.Results show that 2% O2 addition provides the best inactivation efficiency, and the survival rate can be reduced to 7% after 180 s treatment.When the oxygen addition exceeds 2%, the inactivation efficiency gradually weakens.The effect is not so good as that in pure argon plasma when the oxygen addition arrives at 8%.According to the emission spectrum of the plasmum, it is concluded that the reactive oxygen species in the plasma play a key role in cancer cell inactivation process.国家自然科学基金(批准号:11275261;11005151)资助的课题~

The Role of Oxygen in a Large Area of RF-Powered Atmospheric Pressure Dielectric Barrier Glow Discharge Plasma in Sterilization

National Natural Science Foundation of China [11005151, 10735090]A nonequilibrium Ar/O(2) plasma at atmospheric pressure was generated between two parallel square electrodes by a 13.56-MHz power supplier. Experimental results demonstrate that the Ar/O(2) plasma more effectively kills Staphylococcus aureus and Escherichia coli than the Ar plasma. When the O(2) flow rate increases from 0 to 100 sccm step by step, the discharge voltage and the radio-frequency (RF) current always show sinusoidal waveforms, and the discharges maintain the a mode as well. In addition, the sterilization efficiency values of the RF-powered atmospheric pressure Ar/O(2) plasma depend on the oxygen fraction in Ar gas. It is found that the sterilization efficiency of the Ar/O(2) plasma is highest with 0.5 vol.% oxygen in argon gas, corresponding to the maximum production of O((3)P) radicals. It is considered that the O((3)P) radicals produced by the Ar/O(2) plasma play a significant role in atmospheric plasma sterilization