One-pot reduction of HAuCl4 in a DMF solution containing a porphyrin-cored tetradentate passivant gives horizontal porphyrin monolayer-coated gold nanoparticles, whose particle size is significantly smaller than that made by using monodentate passivants under identical conditions.

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Laser is an effective, simple and harmless clinical procedure used for the treatment of hemorrhoids, as an alternative to medical therapy or surgery. In this report, we describe our experience of applying carbon dioxide laser to hemorrhoids in a total 1816 consecutive patients. The results lead us to conclude that the laser treatment of hemorrhoids is effective in pain alleviation from the first session and that patients so treated have a much more comfortable postoperative course.

We previously reported that a porphyrin-cored tetradentate passivant, which has two disulfide straps over one face of the porphyrin plane, can produce monolayer-protected gold nanoparticles, 2-4 nm in size, by the one-pot reduction of HAuCl(4) in DMF. The resulting nanoparticles are smaller than those prepared using the same S/Au molar ratio of a monodentate passivant. To examine the formation mechanism of small gold nanoparticles, the formation of gold nanoparticles in the presence of porphyrin-cored tetradentate passivants or a structurally related monodentate passivant was studied by time-resolved quick X-ray absorption fine structure spectroscopy. The results demonstrated that all of Au ions in solution are reduced to compose small Au clusters, i.e. nuclei, just after the NaBH(4) reduction of HAuCl(4) in both cases, but their size varied with the initial S/Au molar ratios and structure of the passivants. Thus, the size of Au nuclei was kinetically controlled by the passivants. Interestingly, the porphyrin-cored tetradentate passivant could stabilize smaller gold nanoparticles, 2-4 nm in size, but it was less efficient in trapping the Au nuclei formed at a very early stage, in comparison to the monodentate passivant.

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