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Argon Plasma (argon + plasma)

Distribution by Scientific Domains
Medical Sciences50%

Terms modified by Argon Plasma

  • argon plasma coagulation
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    Selected Abstracts

    Gold Coating of Poly(ethylene terephthalate) Modified by Argon Plasma

    PLASMA PROCESSES AND POLYMERS, Issue 1 2007
    Vladimír Kotál
    Abstract Little information has been published concerning the interaction of gold with polymers. In the context of this lack of information, we decided to investigate the effect of Ar plasma treatment on the surface properties of poly(ethylene terephthalate) (PET) in order to examine its possible application for metal-polymer adhesion improvement. The plasma treatment leads to an immediate increase of the PET's surface wettability, which however significantly depends on the sample aging, more specifically on the time elapsed after the treatment. X-ray photoelectron spectroscopy (XPS) measurements revealed that the oxygen concentration in the surface-near layers increases as a result of the treatment, but that it also changes with time for the samples in contact with the atmosphere, probably as a result of polar group rearrangements. Plasma initiated ablation and Au sputtering increases the surface roughness. The nanoindenter measurements revealed that the treatment increases the microhardness of treated PET. Contrary to hardness, the elastic modulus decreases. Scratch tests showed that the deformation of samples consisting of Au coatings deposited on both pristine and treated PET was elastic rather than plastic. We conclude from the nanoindenter data that the plasma modification does not affect the adhesion of gold on PET, but the X-ray diffractometry (XRD) analysis showed that the Au film deposited on the as-treated PET, and on PET aged for 14 d are the most stable. [source]

    Enhanced Chondrogenic Responses of Human Articular Chondrocytes Onto Silk Fibroin/Wool Keratose Scaffolds Treated With Microwave-Induced Argon Plasma

    ARTIFICIAL ORGANS, Issue 5 2010
    Young Woo Cheon
    Abstract Silk fibroin (SF) is a natural, degradable, fibrous protein that is biocompatible, is easily processed, and possesses unique mechanical properties. Another natural material, wool keratose (WK), is a soluble derivative of wool keratin, containing amino acid sequences that induce cell adhesion. Here, we blended SF and WK to improve the poor electrospinability of WK and increase the adhesiveness of SF. We hypothesized that microwave-induced argon plasma treatment would improve chondrogenic cell growth and cartilage-specific extracellular matrix formation on a three-dimensional SF/WK scaffold. After argon plasma treatment, static water contact angle measurement revealed increased hydrophilicity of the SF/WK scaffold, and scanning electron microscopy showed that treated SF/WK scaffolds had deeper and more cylindrical pores than nontreated scaffolds. Attachment and proliferation of neonatal human knee articular chondrocytes on treated SF/WK scaffolds increased significantly, followed by increased glycosaminoglycan synthesis. Our results suggest that microwave-induced, plasma-treated SF/WK scaffolds have potential in cartilage tissue engineering. [source]

    Barrett's esophagus: combined treatment using argon plasma coagulation and laparoscopic antireflux surgery

    DISEASES OF THE ESOPHAGUS, Issue 4 2003
    M. Pagani
    SUMMARY, The treatment of Barrett's esophagus is still controversial. Actually, the only method to prevent the development to cancer is endoscopic surveillance, which ensures good results in terms of long-term survival. An ideal treatment capable of destroying columnar metaplasia, followed by squamous epithelium regeneration could potentially result in a decrease of the incidence of adenocarcinoma. Recently most ablative techniques were used, such as photodynamic therapy, ablation therapy with Nd-YAG laser or argon plasma coagulation and endoscopic mucosal resection. We started a prospective study in January 1998, enrolling 94 patients affected by Barrett's esophagus and candidates for antireflux repair in order to assess the effectiveness and the results of endoscopic coagulation with argon plasma combined with surgery in the treatment of uncomplicated Barrett's esophagus. All patients underwent endoscopic treatment with argon plasma; we observed complete response in 68 patients (72.34%), 27 of them (39.7%) underwent antireflux surgery and the other 41 continued medical therapy. Post-operatively 19 patients (70%) underwent regular surveillance endoscopies and in two cases metaplasia recurred. The final objective of these combined treatments should be the complete eradication of metaplastic mucosa. Our experience was that argon plasma coagulation combined with antireflux surgery or proton pump inhibitor therapy gave satisfactory results, even if follow-up is too short to evaluate the potential evolution of metaplasia to cancer. For this reason, we recommend that this technique should be done only in specialized centres and that these patients continue their endoscopic surveillance program. [source]

    Study of Inductive Coupled Hydrogen and Argon Plasma Interaction with SiO2 Glass

    PLASMA PROCESSES AND POLYMERS, Issue S1 2009
    Atis Skudra
    Abstract This work is devoted to the diagnostics of interaction between hydrogen and argon with the surface of SiO2 glass walls. For diagnostics of the interaction, special high-frequency electrodeless light sources were prepared, filled with pure argon of 1,Torr or argon-hydrogen of total pressure of 1,Torr (Ar/H2 mixing ratio is 9:1). Besides the mostly used spherical and cylindrical lamps, dumbbell type lamps have also been investigated. The spectroscopic and AFM measurements showed that in comparison with pure argon plasma, the argon-hydrogen plasma causes non-uniform changes of the SiO2 surface. For these modifications active OH are primarily responsible molecules, created in the reactions of hydrogen molecules with oxygen molecules, adsorbed from the walls. [source]