Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime of the discharge, where the cross section for electron attachment increases. The formation of negative ions from sputtering of metals and metal oxides is compared with that for positive ions. It is shown that the negative ion signals of F− and TaO2F− are enhanced relative to positive ion signals and can be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible for the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discusse

Detection of negative ions in glow discharge mass spectrometry for analysis of solid specimens

A new method is presented for elemental and molecular analysis of halogen-containing samples by glow discharge time-of-flight mass spectrometry, consisting of detection of negative ions from a pulsed RF glow discharge in argon. Analyte signals are mainly extracted from the afterglow regime of the discharge, where the cross section for electron attachment increases. The formation of negative ions from sputtering of metals and metal oxides is compared with that for positive ions. It is shown that the negative ion signals of F(-) and TaO(2)F(-) are enhanced relative to positive ion signals and can be used to study the distribution of a tantalum fluoride layer within the anodized tantala layer. Further, comparison is made with data obtained using glow-discharge optical emission spectroscopy, where elemental fluorine can only be detected using a neon plasma. The ionization mechanisms responsible for the formation of negative ions in glow discharge time-of-flight mass spectrometry are briefly discussed

Microstructure and properties of the compound layer obtained by pulsed plasma nitriding in steel gears

The crystalline structure profile of the compound layer obtained by pulsed plasma nitriding in steel gears is reported. The nitrogen depth profile obtained by Radio Frequency Glow Discharge Optical Emission Spectroscopy is correlated with both the nano-hardness and the crystalline epsilon-Fe3N/gamma'-Fe4N phases identified in the nitrided layer by X-ray diffraction. These results show the importance to control the nitriding parameters to avoid abrupt hardness changes along the case that can jeopardize the gear performance. (c) 2008 Elsevier B.V. All rights reserved.203419531457146

Microstructure And Properties Of The Compound Layer Obtained By Pulsed Plasma Nitriding In Steel Gears

The crystalline structure profile of the compound layer obtained by pulsed plasma nitriding in steel gears is reported. The nitrogen depth profile obtained by Radio Frequency Glow Discharge Optical Emission Spectroscopy is correlated with both the nano-hardness and the crystalline ε-Fe3N / γ′-Fe4N phases identified in the nitrided layer by X-ray diffraction. These results show the importance to control the nitriding parameters to avoid abrupt hardness changes along the case that can jeopardize the gear performance. © 2008 Elsevier B.V. All rights reserved.20310-1114571461Boniardi, M., D'Errico, F., Tagliabue, C., (2006) Eng. Fail. Anal., 13, p. 312Chiu, L., Wu, C., Chang, H., (2002) Wear, 253, p. 778Psyllaki, P., Kefalonikas, G., Pantazopoulos, G., Antoniou, S., Sideris, J., (2002) Surf. Coat. Technol., 162, p. 67Kim, Y.M., Han, J.G., (2003) Surf. Coat. Technol., 171, p. 205Qiang, Y.H., Ge, S.R., Xue, Q.J., (2000) J. Mater. Process. Technol., 101, p. 180Basso, R.L.O., Candal, R., Figueroa, C.A., Wisnivesky, D., Alvarez, F., (2009) Surf. Coat. Technol., 203, p. 1293. , 10.1016/j.surfcoat.2008.10.006Braga, D., Dias, J.P., Cavaleiro, A., (2006) Surf. Coat. Technol., p. 4861Chala, A., Nouveau, C., Djouadi, M.A., Steyer, P., Millet, J.P., Saied, C., Aida, M.S., Lambertin, M., (2006) Surf. Coat. Technol., 200, p. 6568Bell, T., Sun, Y., Suhadi, A., (2000) Vacuum, 59, p. 14See for instance, Glow Discharge Optical Emission Spectroscopy (Rsc Analytical Spectroscopy Monographs) by T. Nils and R. Payling. Editor: N. Barnett. The Royal Society of Chemistry, Athenaum Press Ltd., Gateshead, Tyne and Wear, UK (2003)Zagonel, L.F., Figueroa, C.A., Droppa Jr., R., Alvarez, F., (2006) Surf. Coat. Technol., 201, p. 452Figueroa, C.A., Weber, S., Czerwiec, T., Alvarez, F., (2006) Sripta Materialia, 54, p. 1335Oliver, W.C., Pharr, G.M., (1993) J. Mater. Res., 7, p. 1564See for instance J. Malzbender, J. of European Ceramic Society, 23, 1355 (2003)K. Abdu Al-Rub, Mech. of Mat., 39, 787 (2007)See for instance, B. Chapman, Glow Discharge Processes, Wiley-Interscience Publications, 1980Figueroa, C.A., Ochoa, E., Alvarez, F., (2003) J. Appl. Phys., 94, p. 2242See for instance, Materials Science and Engineering: An Introduction, William D. Callister, Willey, 2006Medina-Flores, A., Oseguera, J., Santiago, P., Ascencio, J.A., (2004) Surf. Coat. Technol., 188, p. 7L.F. Zagone, E.J. Mittemeijer, F. Alvarez, Mat. Sc. & Tecn. (in press), doi:10.1179/174328408X332780Medina-Flore, A., Oseguera, J., Santiago, P., Ascencio, J.A., (2004) Surf. Coat. Technol., 188-189, p. 7Zagonel, L.F., Alvarez, F., (2007) Mater. Sci. Eng. A, 465, p. 194Somers, M.A.J., Kooi, B.J., Maldzinski, L., Mittemeijer, E.J., Van den Horst, A.A., Van der Kraan, A.M., Van der Pers, N.M., (1997) Acta Mater., 5, p. 2013Basso, R.L.O., Figueroa, C.A., Zagonel, L.F., Pastore, H.O., Wisnivesky, D., Alvarez, F., (2007) Plasma Process Polym., 4, pp. S728Timoshenko, S., (1925) J. Opt. Soc., p. 233Ochoa, E.A., Figueroa, C.A., Alvarez, F., (2005) Surf. Coat. Technol., 200, p. 2165Hu, H.K., Rabalais, J.W., (1981) J. Chem., 85, p. 2459See for instance, Principles of Plasma Discharge and Materials Processing, by M.A. Liberman and A.J. Lichtenberg, Wiley-Interscience Publication, New York, 1994In the experimental conditions used in this work (500 V and 4.0 Torr) the energy of the ions (H2 + and N2 +) impinging the gears due to inelastic scattering losses is E~ 50 eV. See R. Wei, Surf. Coat. Technol. 83, 218 (1996)Winters, H., (1966) J. Chem. Phys., 44, p. 147

Histopathological features due to the SARS-CoV-2

The infection due to the SARS-CoV-2 leads lesions mainly observed at the respiratory tract level, but not exclusively. The analyses of these lesions benefited from different autopsy studies. Thus, these lesions were observed in different organs, tissues and cells. These observations allowed us to rapidly improve the knowledge of the pathophysiological mechanisms associated with this emergent infectious disease. The virus can be detected in formalin fixed paraffin embedded tissues using immunohistochemistry, in situ hybridization, molecular biology and/or electron microscopy approaches. However, many uncertainties are still present concerning the direct role of the SARS-CoV-2 on the different lesions observed in different organs, outside the lung, such as the heart, the brain, the liver, the gastrointestinal tract, the kidney and the skin. In this context, it is pivotal to keep going to increase the different tissue and cellular studies in the COVID-19 positive patients aiming to better understanding the consequences of this new infectious disease, notably considering different epidemiological and co-morbidities associated factors. This could participate to the development of new therapeutic strategies too. The purpose of this review is to describe the main histological and cellular lesions associated with the infection due to the SARS-CoV-2

Symptomatic progestin-associated atypical grade II meningioma. A first case report

International audienc

Amelioration de la gestion des decharges d'ordures menageres et assimilees sous l'angle de leur impact environnemental

Available from INIST (FR), Document Supply Service, under shelf-number : RP 185 (4277) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEMinistere de l'Environnement, 75 - Paris (France). Sous-direction des Produits et des Dechets (SDPD)FRFranc

Clear cell meningiomas are defined by a highly distinct DNA methylation profile and mutations in SMARCE1

Clear cell meningioma represents an uncommon variant of meningioma that typically affects children and young adults. Although an enrichment of loss-of-function mutations in the SMARCE1 gene has been reported for this subtype, comprehensive molecular investigations are lacking. Here we describe a molecularly distinct subset of tumors (n = 31), initially identified through genome-wide DNA methylation screening among a cohort of 3093 meningiomas, of which most were diagnosed histologically as clear cell meningioma. This cohort was further supplemented by an additional 11 histologically diagnosed clear cell meningiomas for analysis (n = 42). Targeted DNA sequencing revealed SMARCE1 mutations in 33/34 analyzed samples, accompanied by a nuclear loss of expression determined via immunohistochemistry and a decreased SMARCE1 transcript expression in the tumor cells. Analysis of time to progression or recurrence of patients within the clear cell meningioma group (n = 14) in comparison to those with meningioma WHO grade 2 (n = 220) revealed a similar outcome and support the assignment of WHO grade 2 to these tumors. Our findings indicate the existence of a highly distinct epigenetic signature of clear cell meningiomas, separate from all other variants of meningiomas, with recurrent mutations in the SMARCE1 gene. This suggests that these tumors may arise from a different precursor cell population than the broad spectrum of the other meningioma subtypes