Study on the thermal stability of Ti(C,O,N) decorative coatings

This work reports on the study of thermal stability of dark decorative Ti(C,O,N) thin films produced by reactive magnetron sputtering, from a pure titanium target, using acetylene and an oxygen and nitrogen mixture as reactive gases. The thermal resistance and evolution of structural and physical properties were studied by performing annealing experiments at three different temperatures: 800, 900 and 1 000 ºC. In order to study the effect of the thermal treatments on the properties of the films, mainly the physical ones (where surface colourations will deserve particular importance), X-ray diffraction (XRD) and Raman spectroscopy (RS) were used. The optical properties of the films were obtained by reflectance experiments, in visible region, and the colour of the films is expressed in the CIE 1976 L a b colour space.Fundação para a Ciência e Tecnologia (FCT) - SFRH/BPD/27114/2006 and PTDC/CTM/69362/2006

Tribological characterisation of magnetron sputtered Ti(C, O, N) thin films

Ti(C, O, N) thin films were prepared by magnetron sputtering and analysed in terms of their tribological properties. Surface and tribological parameters were analysed and discussed as a function of the films composition and structural features, as well as their thickness. The evolution of friction coefficient values was in concordance with the wear behaviour of the films. According to the atomic composition of the films, an increasing of the carbon percentage and a compound chemical formula closed to the stoichiometric TiC lead to a very good wear behaviour. This aspect is also directly correlated with the friction behaviour.Fundação para a Ciência e Tecnologia (FCT) SFRH/BPD/27114/2006 e PTDC/CTM/69362/200

Titanium oxynitride thin films sputter deposited by the reactive gas pulsing process

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Development of dark Ti(C,O,N) coatings prepared by reactive sputtering

Accepted manuscriptDirect current reactive magnetron sputtering was implemented to successfully deposit dark Ti(C,O,N) thin films on silicon substrates. A titanium target was sputtered while a mixture of oxygen and nitrogen was injected into the deposition chamber, independently from an acetylene source. The deposition parameters were chosen as a function of pre-existing knowledge about sputtered Ti–O–N and Ti–C–O films. Tuning the oxygen/(nitrogen+carbon) ratio allowed obtaining a large spectrum of properties. In particular, the colour of the films was characterized by spectral reflectance spectroscopy, and expressed in the CIE 1976 L*a*b* colour space. An accurate control of the reactive gas mixture flow rate allowed obtaining intrinsic, stable and attractive dark colour for decorative applications. Surprisingly, the coatings with the lowest content of carbon and the highest content of oxygen presented the darkest tones. Composition analysis by electron probe microanalysis was done to quantify the titanium and metalloid concentrations in the films. X-ray diffraction experiments revealed the evolution of the film structure from a fcc structure for the lowest (O2+N2) flow rates to an amorphous one for the highest flow rates.Fundação para a Ciência e Tecnologia (FCT) - SFRH/BPD/27114/2006 and PTDC/CTM/69362/2006. CRUP (Acção Integrada Luso-francesa No. F-2307). GRICES/CNRS collaboration (Proc. 4.1.1 França

Tribocorrosion behavior of Ti–C–O–N nanostructured thin films (black) for decorative applications

In the past few years, tribocorrosion has become a focus of research because of its relevance in terms of the future in-service degradation mechanisms of materials. In the particular case of decorative coatings, tribocorrosion is certainly one of the most important issues, and sweat corrosion and human contact wear are two other factors that may act as material selection tools. Thus, the current study aimed to investigate the tribocorrosion behavior of a new class of thin films, the Ti–C–O–N system, which is being developed to be used as a surface decorative material due to its relatively dark appearance. The films were prepared by reactive magnetron sputtering. The influence of the structural features on the tribocorrosion behavior is discussed.This research is supported by FEDER funds through COMPETE-Programa Operacional Factores de Competitividade and by national funds through the Fundacao para a Ciencia e a Tecnologia, project PTDC/CTM/69362/2006 and contract SFRH/BD/27569/2006

Properties changes of Ti(C, O, N) films prepared by PVD : the effect of reactive gases partial pressure

Dark Ti-C-O-N thin films were deposited by dc reactive magnetron sputtering. A titanium target was sputtered while three different gas flows were injected into the deposition chamber: argon (working gas), acetylene and a mixture of oxygen and nitrogen (reactive gases). The films were produced with variation of the gases flow rates, maintaining the remaining parameters constant. Varying the ratio between the reactive gases flow (gas mixture/acetylene) allowed obtaining films with different characteristics. The colour of the films was characterized by spectral reflectance spectroscopy, and expressed in the CIE 1976 L*a*b* colour space. An accurate control of the deposition conditions allowed obtaining intrinsic and stable dark colours for decorative applications. Composition analysis by electron probe microanalysis was done to quantify the elemental concentrations in the films. X-ray diffraction experiments revealed the evolution of the film structure which showed to be essentially amorphous, but with evidences of fcc structure.Fundação para a Ciência e Tecnologia (FCT) - SFRH/BPD/27114/2006 and PTDC/CTM/69362/2006

Evidence for new targets and synergistic effect of metronomic celecoxib/fluvastatin combination in pilocytic astrocytoma.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Pilocytic astrocytomas occur predominantly in childhood. In contrast to the posterior fossa location, hypothalamo-chiasmatic pilocytic astrocytomas display a worse prognosis often leading to multiple surgical procedures and/or several lines of chemotherapy and radiotherapy to achieve long-term control. Hypothalamo-chiasmatic pilocytic astrocytomas and cerebellar pilocytic astrocytomas have a distinctive gene signature and several differential expressed genes (ICAM1, CRK, CD36, and IQGAP1) are targets for available drugs: fluvastatin and/or celecoxib. RESULTS: Quantification by RT-Q-PCR of the expression of these genes was performed in a series of 51 pilocytic astrocytomas and 10 glioblastomas: they were all significantly overexpressed in hypothalamo-chiasmatic pilocytic astrocytomas relative to cerebellar pilocytic astrocytomas, and CRK and ICAM1 were significantly overexpressed in pilocytic astrocytomas versus glioblastomas.We used two commercially available glioblastoma cell lines and three pilocytic astrocytoma explant cultures to investigate the effect of celecoxib/fluvastatin alone or in combination. Glioblastoma cell lines were sensitive to both drugs and a combination of 100 μM celecoxib and 240 μM fluvastatin was the most synergistic. This synergistic combination was used on the explant cultures and led to massive cell death of pilocytic astrocytoma cells.As a proof of concept, a patient with a refractory multifocal pilocytic astrocytoma was successfully treated with the fluvastatin/celecoxib combination used for 18 months. It was well tolerated and led to a partial tumor response. CONCLUSION: This study reports evidence for new targets and synergistic effect of celecoxib/fluvastatin combination in pilocytic astrocytoma. Because it is non-toxic, this new strategy offers hope for the treatment of patients with refractory pilocytic astrocytoma