Structure of Fe-Cu coatings prepared by the magnetron sputtering method

This work presents the results of our research concerning the synthesis of metallic Fe-Cu coatings by use of the magnetron sputtering method. The structure of the coatings synthesized during two modes of pulsed magnetron sputtering was compared . In our experiment the pulsed magnetron power supply generated a series of pulses gated at 1kHz - standard pulsed mode (SPM) and 2 Hz - low frequency pulsed mode (LFPM). The analysis of the microstructure by means of SEM and TEM show that obtained coatings are characterized by nanocrystalline structure. Additionally the optical emission spectra (OES) during the copper and iron sputtering were measured

The role of magnetic energy on plasma localization during the glow discharge under reduced pressure

In this work, we present the first results of our research on the synergy of fields, electric and magnetic, in the initiation and development of glow discharge under reduced pressure. In the two-electrode system under reduced pressure, the breakdown voltage characterizes a minimum energy input of the electric field to initiate and sustain the glow discharge. The glow discharge enhanced by the magnetic field applied just above the surface of the cathode influences the breakdown voltage decreasing its value. The idea of the experiment was to verify whether the contribution of potential energy of the magnetic field applied around the cathode is sufficiently effective to locate the plasma of glow discharge to the grounded cathode, which, in fact, is the part of a vacuum chamber wall (the anode is positively biased in this case). In our studies, we used the grounded magnetron unit with positively biased anode in order to achieve favorable conditions for the deposition of thin films on fibrous substrates such as fabrics for metallization, assuming that locally applied magnetic field can effectively locate plasma. The results of our studies (Paschen curve with the participation of the magnetic field) seem to confirm the validity of the research assumption. What is the most spectacular – the glow discharge was initiated between introduced into the chamber anode and the grounded cathode of magnetron ‘assisted’ by the magnetic field (discharge did not include the area of the anode, which is a part of the magnetron construction)

Determination of SP3 fraction in ta-C coating using XPS and Raman spectroscopy

The paper presents results of studies on the structure of tetrahedral amorphous carbon films (ta-C) with a thickness in the range from 20 to 280 nm, deposited using pulsed vacuum arc technique with an electromagnetic Venetian blind plasma filter. The results of the phase structure analysis, obtained using visible Raman spectroscopy and UV Raman spectroscopy methods, showed a strong dependence of the results on the presence, on the surface of synthesized thin carbon films, even of a minimum number of microparticles. The presence of microparticles in the deposited coatings strongly affects the accuracy of the measured data, used next for calculation the ID/IG, IT/IG ratios and determination of the G-peak dispersion, for all coating thicknesses, which pointed to significant diversification in sp3-bonds content in deposited films.</p

Structure and Electrical Resistivity Dependence of Molybdenum Thin Films Deposited by DC Modulated Pulsed Magnetron Sputtering

This work reports the results of a study of Mo thin films synthesis by DC Pulsed Magnetron Sputtering method (PMS), operating at pulse main frequency of 100 kHz and modulated by the additional modulation frequency, driving in the range of 5-1000 Hz (modulated Pulse Magnetron Sputtering – mPMS). We have studied the influence of mPMS on plasma chemical reactions and mechanisms of layer growth using optical emission spectroscopy technique. Our experiment showed strong influence of mPMS method, on the morphology (scanning electron microscopy), phase composition (X-ray diffractometry) and electric properties (4-point probes method) of nanocrystalline and amorphous Mo films. From the utilitarian point of view, low value of resistivity – 43,2 μΩcm of synthesized Mo films predestines them as back contacts for thin solar cells CIGS. Our results revealed that additional modulation frequency should be considered as an important factor for optimization of films synthesis by means of PMS-based methods

Diamond, graphite, and graphene oxide nanoparticles decrease migration and invasiveness in glioblastoma cell lines by impairing extracellular adhesion

Mateusz Wierzbicki,1 Sławomir Jaworski,1 Marta Kutwin,1 Marta Grodzik,1 Barbara Strojny,1 Natalia Kurantowicz,1 Krzysztof Zdunek,2 Rafał Chodun,2 Andr&eacute; Chwalibog,3 Ewa Sawosz1 1Division of Nanobiotechnology, Warsaw University of Life Science, 2Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland; 3Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark Abstract: The highly invasive nature of glioblastoma is one of the most significant problems regarding the treatment of this tumor. Diamond nanoparticles (ND), graphite nanoparticles (NG), and graphene oxide nanoplatelets (nGO) have been explored for their biomedical applications, especially for drug delivery. The objective of this research was to assess changes in the adhesion, migration, and invasiveness of two glioblastoma cell lines, U87 and U118, after ND, NG, and nGO treatment. All treatments affected the cell surface structure, adhesion-dependent EGFR/AKT/mTOR, and &beta;-catenin signaling pathways, decreasing the migration and invasiveness of both glioblastoma cell lines. The examined nanoparticles did not show strong toxicity but effectively deregulated cell migration. ND was effectively taken up by cells, whereas nGO and NG strongly interacted with the cell surface. These results indicate that nanoparticles could be used in biomedical applications as a low toxicity active compound for glioblastoma treatment. Keywords: diamond, graphene oxide, graphite, nanoparticles, glioblastoma, migration, invasivenes