Simple Fabrication of Silicon Nanowires by Zinc-Thermal Reduction of Silicon Tetrachloride at 773 K

This paper reports a simple Si nanowire (SiNW) production process based on zinc-thermal reduction of SiCl₄ in a sealed Pyrex® tube at 773 K. SiNWs with a diameter of about 300 nm were produced without any catalysts. The SiNWs consisted mainly of an amorphous phase, but also including a minor microcrystalline component. The introduction of Au nanoparticles to the reaction tube wall facilitated crystallization and resulted in the growth of thinner SiNWs. The typical diameter of these SiNWs was 10–20 nm. The simple apparatus and low operating temperature of this new process are advantageous in producing SiNWs on both industrial and laboratory scales

SIRT1 Regulates Thyroid-Stimulating Hormone Release by Enhancing PIP5Kγ[subscript gamma] Activity through Deacetylation of Specific Lysine Residues in Mammals

Background: SIRT1, a NAD-dependent deacetylase, has diverse roles in a variety of organs such as regulation of endocrine function and metabolism. However, it remains to be addressed how it regulates hormone release there. Methodology/Principal Findings: Here, we report that SIRT1 is abundantly expressed in pituitary thyrotropes and regulates thyroid hormone secretion. Manipulation of SIRT1 level revealed that SIRT1 positively regulated the exocytosis of TSH-containing granules. Using LC/MS-based interactomics, phosphatidylinositol-4-phosphate 5-kinase (PIP5K)γ[subscript gamma] was identified as a SIRT1 binding partner and deacetylation substrate. SIRT1 deacetylated two specific lysine residues (K265/K268) in PIP5Kγ[subscript gamma] and enhanced PIP5Kγ[subscript gamma] enzyme activity. SIRT1-mediated TSH secretion was abolished by PIP5Kγ[subscript gamma] knockdown. SIRT1 knockdown decreased the levels of deacetylated PIP5Kγ, PI(4,5)P[subscript 2], and reduced the secretion of TSH from pituitary cells. These results were also observed in SIRT1-knockout mice. Conclusions/Significance: Our findings indicated that the control of TSH release by the SIRT1-PIP5Kγ[subscript gamma] pathway is important for regulating the metabolism of the whole body.Mitsubishi Institute of Life SciencesJapan Society for the Promotion of Science. (WAKATE S grant