Nitrogen determination in micas of metamorphic rocks

6 pages, 1 table, 1 figure.-- Proceedings of the Seventeenth International Conference on Ion Beam Analysis.-- El pdf del artículo es la versión post-print.-- et al.Micas are minerals that provide large amounts of information regarding geological processes, because of the sensitivity of their chemical composition to temperature, pressure and deformation of rocks in which they form. Rocks under analysis are formed of different minerals with variable grain size. Mica grain size may vary between 5 and 10 μm and approximately correspond to the chemical formula (Si3.2Al0.8)O10(Al1.9Fe0.05Mg0.1)(OH)2(K0.75Na0.05), being distinguishable from other minerals because of their composition and their morphology in secondary electron images and specially backscattered electron (BSE) images. NH4, when present, would partially substitute K in the previous formula. In some cases NH4-rich micas (tobelites) have been described coexisting with the corresponding K-rich micas, but the actual NH4 content of normal K-rich micas is still unknown. Low N content makes necessary to use nuclear reactions such as 14N(d, pγ)15N at 1.4 MeV and its cascade of intense γ-rays. For the quantification and localization of nitrogen on the surface of the samples, PIGE analysis was carried out in the vacuum microprobe line of the CNA, together with simultaneous micro-RBS and micro-PIXE analyses, giving a more comprehensive picture of sample structure and composition.Peer reviewe

Geographical variation in serological responses to recombinant Pneumocystis jirovecii major surface glycoprotein antigens

AbstractThe use of recombinant fragments of the major surface glycoprotein (Msg) of Pneumocystis jirovecii has proven useful for studying serological immune responses of blood donors and human immunodeficiency virus (HIV)-positive (HIV+) patients. Here, we have used ELISA to measure antibody titres to Msg fragments (MsgA, MsgB, MsgC1, MsgC3, MsgC8 and MsgC9 in sera isolated in the USA (n=200 and Spain (n=326), to determine whether geographical location affects serological responses to these antigens. Blood donors from Seville exhibited a significantly greater antibody titre to MsgC8, and significantly lower responses to MsgC3 and MsgC9, than did Cincinnati (USA) donors. Spanish blood donors (n=162 also exhibited elevated responses to MsgC1, MsgC8 and MsgC9 as compared with Spanish HIV+ (n=patients. HIV+ patients who had Pneumocystis pneumonia (PcP+) exhibited a higher response to MsgC8 than did HIV+ PcP- patients. These data show that geographical location plays a role in responsiveness to Msg fragments. Additionally, these fragments have utility in differentiating HIV+ PcP and HIV+ PcP+ among patient populations

Nitrogen determination in micas of metamorphic rocks

Micas are minerals that provide large amounts of information regarding geological processes, because of the sensitivity of their chemical composition to temperature, pressure and deformation of rocks in which they form. Rocks under analysis are formed of different minerals with variable grain size. Mica grain size may vary between 5 and 10 μm and approximately correspond to the chemical formula (Si3.2Al0.8)O10(Al1.9Fe0.05Mg0.1)(OH)2(K0.75Na0.05), being distinguishable from other minerals because of their composition and their morphology in secondary electron images and specially backscattered electron (BSE) images. NH4, when present, would partially substitute K in the previous formula. In some cases NH4-rich micas (tobelites) have been described coexisting with the corresponding K-rich micas, but the actual NH4 content of normal K-rich micas is still unknown. Low N content makes necessary to use nuclear reactions such as 14N(d, pγ)15N at 1.4 MeV and its cascade of intense γ-rays. For the quantification and localization of nitrogen on the surface of the samples, PIGE analysis was carried out in the vacuum microprobe line of the CNA, together with simultaneous micro-RBS and micro-PIXE analyses, giving a more comprehensive picture of sample structure and composition