大气压冷等离子体射流灭活子宫颈癌Hela细胞

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18 W, 在900 mL/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180 s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. 关键词： 大气压冷等离子体射流 Hela癌细胞 存活率 发射光谱     

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研究了氮氧源大气压等离子体射流对表面大肠杆菌灭活作用,分析了氮氧源大气压等离子体射流的光谱性质.结果表明,在放电电压为6.8kV,气体流速为4L?min-1,处理3min时,氮氧比为1:4的大气压等离子体射流对大肠杆菌的灭活率达到98.4%,接近氧气源大气压等离子体射流灭菌效果.通过大气压等离子体射流发射光谱(OES)分析了氮氧源大气压等离子体射流中活性物质,进而解释大肠杆菌微生物灭活机理,认为NO-γ、OI、·OH等活性物质在表面大肠杆菌灭活过程中起到了重要作用.这将为大气压氮氧等离子体射流在环境卫生、微生物灭活等方面的应用研究提供实验基础和技术支持.     

大气压氮氧等离子体射流灭活表面大肠杆菌及其发射光谱分析研究

研究了氮氧源大气压等离子体射流对表面大肠杆菌灭活作用,分析了氮氧源大气压等离子体射流的光谱性质。结果表明,在放电电压为6.8kV,气体流速为4L?min?1,处理3min时,氮氧比为1:4的大气压等离子体射流对大肠杆菌的灭活率达到98.4%,接近氧气源大气压等离子体射流灭菌效果。通过大气压等离子体射流发射光谱(OES)分析了氮氧源大气压等离子体射流中活性物质,进而解释大肠杆菌微生物灭活机理,认为NO?γ、OI、?OH等活性物质在表面大肠杆菌灭活过程中起到了重要作用。这将为大气压氮氧等离子体射流在环境卫生、微生物灭活等方面的应用研究提供实验基础和技术支持。     

大气条件等离子体针处理Enterococcus faecalis菌

自行研制的等离子体针在大气压下通过介质阻挡放电产生的等离子体,再由喷嘴处安装的漏斗形装置聚焦形成针状等离子体. 然后对针状等离子体的基本特性和杀Enterococcus faecalis(E. faecalis)菌进行了研究,E. faecalis菌是一种引起完善充填根管再感染的主要微生物. 当等离子体针功率为5-28W时,对等离子体的温度进行了测量,表明它不同于其他热杀菌方式. 通过改变等离子体针内电极末端注入的氧气量,发现适当的氧气量,不仅增加等离子体内含氧粒子的浓度而且对等离子体的长度影响也不明显. 实验表明最佳参数为功率15W,0.1m3·h-1氦和2.5%氧气,间距12mm,处理时间30 s. 为了找出杀菌的关键粒子,进一步比较了大气压下的等离子体针的发射光谱与agar(琼脂)2mm下的光谱并找出关键粒子.     

氧等离子体处理对淬火YBa2Cu3Oy的影响

本文研究了氧等离子体处理对YBa2Cu3Oy超导性的影响.在室温下,电离氧气产生氧等离子体,用它对淬火YBa2CuOy样品进行处理,结果表明:经氧等离子体处理的淬火YBa2CuOy样品能在短时间内产生90K相,而且90K相的含量随处理时间的增加而增加,但它们的含氧量并没有增加.实验结果预示:在室温下,氧等离子体能"整理"YBa2Cu3Oy超导体的Cu(1)-O面中a轴上的氧空位并使其有序,而在b轴上形成Cu(1)-O链,产生90K相.     

大气条件等离子体针处理Enterococcus faecalis菌

自行研制的等离子体针在大气压下通过介质阻挡放电产生的等离子体,再由喷嘴处安装的漏斗形装置聚焦形成针状等离子体. 然后对针状等离子体的基本特性和杀Enterococcus faecalis（E. faecalis）菌进行了研究,E. faecalis菌是一种引起完善充填根管再感染的主要微生物. 当等离子体针功率为5—28?W时,对等离子体的温度进行了测量,表明它不同于其他热杀菌方式. 通过改变等离子体针内电极末端注入的氧气量,发现适当的氧气量,不仅增加等离子体内含氧粒子的浓度而且对等离子体的长度影响也不明显. 实验表明最佳参数为功率15?W,0.1?m³·h^-1氦和2.5%氧气,间距12?mm,处理时间30 s. 为了找出杀菌的关键粒子,进一步比较了大气压下的等离子体针的发射光谱与agar（琼脂）2?mm下的光谱并找出关键粒子. 关键词： 大气压等离子体 介质阻挡放电 E. faecalis菌')" href="#">E. faecalis菌 光谱     

氦氮氧混合气湿度计算及实验研究

在海洋科学考察与海洋资源开发的潜水作业中,通常都采用以氦气为主要成分的氦氮氧混合气(以下简称氦混合气)做深潜的呼吸气。氦的热力学性质与空气的有很大差别。氦气的导热系数为空气的五倍多,因此潜水员对氦混合气环境的温度和湿度都极为敏感;氦气的质量比热约为空气的六倍,适用于空气的湿度计算式及干湿球温度与相对湿度的对照表不能用于氦混合气。显然,精确测定并计算氦混合气的湿度,对推动潜水科学     

同轴空心阴极氦等离子体的电子激发温度研究

利用同轴空心阴极放电装置,产生氦低温等离子体。通过对等离子体的发射光谱进行测量和计算,研究放电功率以及氦气压强对等离子体的电子激发温度的影响。结果表明:氦低温等离子体的发射光谱主要由连续谱和原子谱线构成,放电功率和压强对谱线的强度具有明显影响。压强的变化不仅影响电子从电场中获得的能量,还会影响电子与原子的碰撞频率,从而导致电子激发温度随着氦气压强的增大,出现先上升后下降的变化趋势。     

甲基化抑制剂5-氮杂2′-脱氧胞苷对三维培养A549细胞辐射敏感性的影响

为探讨DNA去甲基化试剂5-氮杂-2′-脱氧胞苷(5-aza-2′-deoxycytidine,5-Aza-CdR)对三维(3D)培养模式下的肺腺癌细胞A549辐射敏感性的作用,开展了系列实验。使用不同浓度5-Aza-CdR处理单层(2D)A549细胞72 h后,MTT法检测其对A549细胞的增殖抑制作用。选取低浓度(2,5μmol/L)5-Aza-CdR预处理2D和3D培养的A549细胞72 h,X射线分别辐照1,2,4,6 Gy,检测微核形成率和克隆存活。实验结果显示,不同浓度的5-Aza-CdR均能抑制2D的A549细胞增殖,且呈剂量依赖性。5μmol/L药物预处理2D与3D细胞并联合辐照后诱导的细胞微核形成率均显著高于相应的对照组,并且细胞存活率显著降低。不过,较低浓度5-Aza-CdR(2μmol/L)预处理的3D培养A549细胞4,6 Gy辐照后微核数目较未用药处理组显著增加,克隆存活率较未用药组显著降低(P0.05),而在2D培养A549细胞中未观测到上述现象。研究结果表明,5-Aza-CdR能抑制A549细胞增殖,3D培养A549细胞药物预处理更能增加其辐射敏感性。结果暗示,为减少对正常细胞的毒性作用,在临床放疗中,可低剂量使用5-Aza-CdR,实现肿瘤的有效靶向治疗。     

利用氧等离子体处理阳极银实现高效率顶发射有机电致发光

主要报道在器件结构为玻璃衬底/Ag(阳极)/NPB(空穴传输层)/Alq3(电子传输及发光层)/Sm(半透明阴极)/Alq3的顶发射有机电致发光器件中,利用氧等离子体对阳极银的表面进行处理来降低阳极和空穴传输层(Ag/NPB)界面处的空穴注入势垒,提高顶发射有机电致发光器件的性能。主要研究了氧等离子体处理时间对阳极银和顶发射有机电致发光器件光电特性的影响。紫外光电子能谱表明,氧等离子体处理能有效降低Ag/NPB界面处的空穴注入势垒。通过优化处理时间获得最佳器件性能,优化后的器件最大效率可达6.14cd/A。     

The influence of moisture on atmospheric pressure plasma etching of PA6 films

The moisture in the substrate material may have a potential influence on atmospheric pressure plasma treatment. In order to investigate how the existence of moisture affects atmospheric pressure plasma treatment, polyamide 6 (PA6) films were treated by helium, helium/oxygen (O₂) plasmas using atmospheric pressure plasma jet (APPJ) at different moisture regain. The film surfaces were investigated using contact-angle measurements, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to characterize the surfaces. The exposure of PA6 film surfaces to the plasmas led to the etching process on the surfaces and changes in the topography of the surfaces. It was shown that the etching rate and the surface roughness were higher for the 9.33% moisture regain (relative humidity 100%) group than that of the 1.61% moisture regain (relative humidity 10%) group with the same plasma gas and power.     

Surface modification of a polyamide 6 film by He/CF4 plasma using atmospheric pressure plasma jet

Polyamide 6 (PA 6) films are treated with helium(He)/CF₄ plasma at atmospheric pressure. The samples are treated at different treatment times. The surface modification of the PA 6 films is evaluated by water contact angle, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The etching rate is used to study the etching effect of He/CF₄ plasma on the PA 6 films. The T-peel strengths of the control and plasma treated films are measured to show the surface adhesion properties of the films. As the treatment time increases, the etching rate decreases steadily, the contact angle decreases initially and then increases, while the T-peel strength increases first and then decreases. AFM analyses show that the surface roughness increases after the plasma treatment. XPS analyses reveal substantial incorporation of fluorine and/or oxygen atoms to the polymer chains on the film surfaces.     

Escherichia coli deactivation study controlling the atmospheric pressure plasma discharge conditions

Bio-applications of plasma have been widely studied in recent years. However, considering the high interests, the inactivation mechanisms of micro-organisms by plasma have not been clearly explained. The goal of this study was to find the sterilization mechanisms and define the major sterilization factors with the atmospheric pressure radio-frequency helium glow discharge. For the sterilization target the Escherichia coli was used. To begin with the sterilization study, the plasma characteristics were investigated by means of electrical and optical diagnostics. Especially, the gas temperature was controlled under 50 °C by keeping the input power less than 70 W to eliminate the thermal effects. Contribution of the UV irradiation from the plasma was studied and it turned out to be negligible. On the other hand, it was found that the sterilization was more effective up to 40% with only 0.15% oxygen addition to the helium supply gas. It indicates that the inactivation process was dominantly controlled by oxygen radicals, rather than heat or UV photons.     

Long-distance oxygen plasma sterilization: Effects and mechanisms

The distribution of electrons, ions and oxygen radicals in long-distance oxygen plasma and the germicidal effect (GE) of Escherichia coli on the surface of medical poly(tetrafluoroethylene) (PTFE) film were studied. The quantity of protein leakage and the production of lipid peroxide in bacterial suspension as well as the state of DNA were measured after sterilization to analyse the inactivation mechanisms. The results showed that the concentration of electrons and ions decreased rapidly with increasing the distance from the center of induction coil, which approximated to 0 at 30 cm, whereas the concentration of oxygen radicals reduced slowly, i.e. decreased 30% within 40 cm. GE value reached 3.42 in the active discharge zone (0 cm) and exceeded 3.32 within 40 cm when plasma treatment parameters were set as follows: plasma rf power at 100 W, treatment time at 60 s and oxygen flux at 40 cm³/min. Fast etching action on cell membrane by electrons, ions and attacking polyunsaturation fatty acid (PUFA) in cell membrane by oxygen radicals are primary reasons of oxygen plasma sterilization in the active discharge and the afterglow zone, respectively. The GE of UV radiation in long-distance oxygen plasma is feebleness.     

Modification of surface properties of polyamide 6 films with atmospheric pressure plasma

To investigate the effect of the different plasma gases treatment on the surface modification of atmospheric pressure plasma, polyamide 6 films were treated using pure helium (He), He/O₂ and He/CF₄, respectively. Atomic force microscopy (AFM) showed rougher surface, while X-ray photoelectron spectroscopy (XPS) revealed increased oxygen and fluorine contents after the plasma treatments. The plasma treated samples had lower water contact angles and higher T-peel strength than that of the control. The addition of small amount of O₂ or CF₄ to He plasma increases the effectiveness of the plasma treatment in polymer surface modification in terms of surface roughness, surface hydrophilic groups, etching rate, water contact angle and bonding strength.     

Physical and electrical characteristics of Ba(Zr0.1Ti0.9)O3 thin films under oxygen plasma treatment for applications in nonvolatile memory devices

In this study, the effects of oxygen gas plasma treatment on the surface of Ba(Zr_0.1Ti_0.9)O₃ (BZT) films are investigated. The influence of oxygen plasma treatment on the crystal structure is developed by X-ray diffraction patterns and on the electrical characteristics are measured by the Al/BZT/Pt capacitor (metal–dielectric–metal) structure. Experimental results show that the capacitance increases and the leakage current density decreases as the oxygen plasma is treated on the BZT films. These results clearly indicate that the electrical characteristics of BZT films have effectively improved by means of the oxygen plasma surface treatment process. PACS 77.84.-s; 81.15.Cd; 73.40.Qv; 77.22.Ej; 51.50.+v     

Removal of paper microbial contamination by atmospheric pressure DBD discharge

In this paper the removal of the microbial contamination from paper material using the plasma treatment at atmospheric pressure is investigated. The Aspergillus niger has been chosen as a bio-indicator enabling to evaluate the effect of plasma assisted microbial inactivation. Dielectric barrier discharge (DBD) operated at atmospheric pressure was used for the paper sterilization. The working gas (nitrogen, argon and helium), plasma exposition time and the plasma power density were varied in order to see the effect of the plasma treatment on the fungi removal. After the treatment, the microbial abatement was evaluated by the standard plate count method. This proved a positive effect of the DBD plasma treatment on fungi removal. Morphological and colorimetric changes of paper substrate after plasma treatment were also investigated.