In this paper,an absorption spectroscopy measurement method was applied on two atmospheric pressure plasma sources to determine their production of nitric oxide.The concentrations are essential for evaluating the plas...In this paper,an absorption spectroscopy measurement method was applied on two atmospheric pressure plasma sources to determine their production of nitric oxide.The concentrations are essential for evaluating the plasma sources based on the principle of the Dielectric Barrier Discharge（DBD）for applications in plasma medicine.The described method is based on a setup with an electrodeless discharge lamp filled with a mixture of oxygen and nitrogen.One of the emitted wavelengths is an important resonance wavelength of nitric oxide（λ = 226.2 nm）.By comparing the absorption behaviour at the minimum and maximum of the spectral absorption cross section of nitric oxide around that wavelength,and measuring the change in intensity by the absorbing plasma,the concentration of nitric oxide inside the plasma can be calculated.The produced nitric oxide concentrations depend on the pulse duration and are in the range of 180 ppm to 1400 ppm,so that a distance of about 10 cm to the respiratory tract is enough to conform to the VDI Guideline 2310.展开更多
In this study two plasma sources were used for an in vivo treatment of human stratum corneum. The sample preparation was realised with the Cyanoacrylat stripping method, whereby a few layers of corneocytes embedded in...In this study two plasma sources were used for an in vivo treatment of human stratum corneum. The sample preparation was realised with the Cyanoacrylat stripping method, whereby a few layers of corneocytes embedded in the lipid matrix were removed from the skin of healthy volunteers. For the plasma treatment, dielectric barrier discharges with pulse durations in the microsecond as well as in the nanosecond range were applied. A comparison of these sources with respect to their biologically active components including dissipated power, gas and electron temperature, irradiance in the ultraviolet range, ozone and nitric oxide concentration is presented. Furthermore, species generated during plasma treatment on the sample surface like hydrogen peroxide, nitride or nitrate were measured using reflectometry. In addition, safety aspects for both sources were evaluated. Resulting plasma induced changes in the sample composition were investigated through X-ray photoelectron spectroscopy. The main ingredients carbon, oxygen, and nitrogen in addition to minor concentrations of sulphur were considered. A significant influence of the pulse duration on plasma characteristics was shown. A more effective formation of reactive species as well as more intense UV emission for ns-plasma was observed. Based on the determined parameters, both plasma sources are suitable for therapeutic purpose. Furthermore, significant plasma induced changes in the stratum corneum composition were reported, including an increase in nitrogen and oxygen content.展开更多
In this work, the suitability of lipid stripping as an alternative model of stratum corneum for plasma medical studies was investigated. Plasma treatment experiments were performed on samples prepared by the cyanoacry...In this work, the suitability of lipid stripping as an alternative model of stratum corneum for plasma medical studies was investigated. Plasma treatment experiments were performed on samples prepared by the cyanoacrylat stripping method. Therefore, two different dielectric barrier discharge-based plasma sources driven by high-voltage pulses in the microsecond and nanosecond range were applied. The lipid sample heating, change in pH-value, and the interaction with plasma-induced UV-radiation are presented and discussed with respect to existing findings on skin samples. After the plasma treatment, the lipid stripping shows similar changes compared to human skin relating to sample heating and pH-value. The investigation of the interplay with UV- radiation shows a high absorption in the wavelength range of 250 nm up to 400 nm. Further, the thickness, surface structure, and composition of lipid stripping samples were determined. The stripped sample shows a thickness of 3 ± 1 μm whereby approximately 30% of the sample surface is covered by lipids. In addition, it was shown that there are no changes in structure caused by the sample preparation. Based on the results of this work, it can be stated that lipid stripping represents an appropriate skin model for plasma medical investigations.展开更多
A novel optimization procedure for optical precision sputter coaters with respect to the film homogeneity is demonstrated. For a coater concept based on dual cylindrical sputtering sources and a rotating turn-table as...A novel optimization procedure for optical precision sputter coaters with respect to the film homogeneity is demonstrated. For a coater concept based on dual cylindrical sputtering sources and a rotating turn-table as sample-holder, the inherent radial decay of the film thickness must be compensated by shaper elements. For that purpose, a simulation model of the particle flux within such a coater is set up and validated against experimental data. Subsequently, the shaper design is optimized according to the modeled metal flux profile. The resulting film thickness deviations are minimized down to ±0.3.5%展开更多
文摘In this paper,an absorption spectroscopy measurement method was applied on two atmospheric pressure plasma sources to determine their production of nitric oxide.The concentrations are essential for evaluating the plasma sources based on the principle of the Dielectric Barrier Discharge（DBD）for applications in plasma medicine.The described method is based on a setup with an electrodeless discharge lamp filled with a mixture of oxygen and nitrogen.One of the emitted wavelengths is an important resonance wavelength of nitric oxide（λ = 226.2 nm）.By comparing the absorption behaviour at the minimum and maximum of the spectral absorption cross section of nitric oxide around that wavelength,and measuring the change in intensity by the absorbing plasma,the concentration of nitric oxide inside the plasma can be calculated.The produced nitric oxide concentrations depend on the pulse duration and are in the range of 180 ppm to 1400 ppm,so that a distance of about 10 cm to the respiratory tract is enough to conform to the VDI Guideline 2310.
文摘In this study two plasma sources were used for an in vivo treatment of human stratum corneum. The sample preparation was realised with the Cyanoacrylat stripping method, whereby a few layers of corneocytes embedded in the lipid matrix were removed from the skin of healthy volunteers. For the plasma treatment, dielectric barrier discharges with pulse durations in the microsecond as well as in the nanosecond range were applied. A comparison of these sources with respect to their biologically active components including dissipated power, gas and electron temperature, irradiance in the ultraviolet range, ozone and nitric oxide concentration is presented. Furthermore, species generated during plasma treatment on the sample surface like hydrogen peroxide, nitride or nitrate were measured using reflectometry. In addition, safety aspects for both sources were evaluated. Resulting plasma induced changes in the sample composition were investigated through X-ray photoelectron spectroscopy. The main ingredients carbon, oxygen, and nitrogen in addition to minor concentrations of sulphur were considered. A significant influence of the pulse duration on plasma characteristics was shown. A more effective formation of reactive species as well as more intense UV emission for ns-plasma was observed. Based on the determined parameters, both plasma sources are suitable for therapeutic purpose. Furthermore, significant plasma induced changes in the stratum corneum composition were reported, including an increase in nitrogen and oxygen content.
基金supported by the European Regional Development Funds(EFRE)and the Workgroup Innovative Projects of Lower Saxony(AGiP)in the frame of the Lower Saxony Innovation Network for Plasma Technology(NIP),project funding reference number W2-80029388.
文摘In this work, the suitability of lipid stripping as an alternative model of stratum corneum for plasma medical studies was investigated. Plasma treatment experiments were performed on samples prepared by the cyanoacrylat stripping method. Therefore, two different dielectric barrier discharge-based plasma sources driven by high-voltage pulses in the microsecond and nanosecond range were applied. The lipid sample heating, change in pH-value, and the interaction with plasma-induced UV-radiation are presented and discussed with respect to existing findings on skin samples. After the plasma treatment, the lipid stripping shows similar changes compared to human skin relating to sample heating and pH-value. The investigation of the interplay with UV- radiation shows a high absorption in the wavelength range of 250 nm up to 400 nm. Further, the thickness, surface structure, and composition of lipid stripping samples were determined. The stripped sample shows a thickness of 3 ± 1 μm whereby approximately 30% of the sample surface is covered by lipids. In addition, it was shown that there are no changes in structure caused by the sample preparation. Based on the results of this work, it can be stated that lipid stripping represents an appropriate skin model for plasma medical investigations.
文摘A novel optimization procedure for optical precision sputter coaters with respect to the film homogeneity is demonstrated. For a coater concept based on dual cylindrical sputtering sources and a rotating turn-table as sample-holder, the inherent radial decay of the film thickness must be compensated by shaper elements. For that purpose, a simulation model of the particle flux within such a coater is set up and validated against experimental data. Subsequently, the shaper design is optimized according to the modeled metal flux profile. The resulting film thickness deviations are minimized down to ±0.3.5%
