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Protein phosphatase-1 (PP1) is a major protein Ser/Thr phosphatase in eukaryotic cells. Its activity depends on two metal ions in the catalytic site, which were identified as manganese in the bacterially expressed phosphatase. However, the identity of the metal ions in native PP1 is unknown. In this study, total reflection X-ray fluorescence (TXRF) was used to detect iron and zinc in PP1 that was purified from rabbit skeletal muscle. Metal exchange experiments confirmed that the distinct substrate specificity of recombinant and native PP1 is determined by the nature of their associated metals. We also found that the iron level associated with native PP1 is decreased by incubation with inhibitor-2, consistent with a function of inhibitor-2 as a PP1 chaperone. [ABSTRACT FROM AUTHOR]

N3-functionalized monolayers on silicon wafer substrates are prepared via the controlled vapor-phase deposition of 11-azidoundecyltrimethoxysilanes at reduced pressure and elevated temperature. The quality of the layer is assessed using contact angle, attenuated total reflectance Fourier transform infrared spectroscopy (ATR–FTIR), and ellipsometry measurements. At 60 °C, longer deposition times are needed to achieve monolayers with similar N3 density compared to depositions at 145 °C. The monolayers formed via the vapor phase are denser compared to those formed via a solvent-based deposition process. ATR–FTIR measurements confirm the incorporation of azido-alkyl chains in the monolayer and the formation of siloxane bridges with the underlying oxide at both deposition temperatures. X-ray photon spectroscopy shows that the N3 group is oriented upward in the grafted layer. Finally, the density was determined using total reflection X-ray fluorescence after a click reaction with chlorohexyne and amounts to 2.5 × 1014 N3 groups/cm2. In summary, our results demonstrate the formation of a uniform and reproducible N3-containing monolayer on silicon wafers, hereby providing a functional coating that enables click reactions at the substrate. [ABSTRACT FROM AUTHOR]

Abstract: Further improving complementary metal oxide semiconductor (CMOS) performance beyond the 15nm generation likely requires the use of high mobility materials like Ge for pMOS devices. However, Ge pMOS devices made in relaxed Ge do not out-perform current state-of-the-art uni-axially strained Si pMOS devices. This explains the current interest in compressively strained Ge like bi-axially strained Ge grown on top of SiGe strain relaxed buffers. From a device integration point of view, the surface smoothness of the strained Ge layer is an important parameter, which has so far not widely been reported in literature, in contrast to other parameters like the material quality (crystallinity) and the threading dislocation density. In this paper we report the capability of chemical mechanical polishing (CMP) to reduce the surface roughness of the SiGe strain relaxed buffers and the post-CMP and pre-epi cleans, which are required to obtain contamination free SiGe surfaces and to enable nearly defect free strained Ge growth without re-occurrence of the surface roughening. We will demonstrate the epitaxial growth of fully strained 20–40nm-thick Ge epitaxially grown on top of SiGe strain relaxed buffers with 85% Ge with a surface roughness as low as 1.6Å (measured on areas of 10×10μm2). [Copyright &y& Elsevier]