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Hydrogen evolution using photocatalytic systems based on artificial photosynthesis is a major approach toward solar energy conversion and storage. In the polyoxometalate-based photocatalytic systems proposed in the past, middle/near UV light irradiation and noble-metal catalysts were mainly used. Although recently polyoxometalates were sensitized in visible light, photosensitizers or catalysts based on noble metals, and/or poor activity of polyoxometalates were generally obtained. Here we show the highly efficient [turnover number (TON)=215] hydrogen evolution induced by the zinc(II) mesotetrakis(N-methyl-pyridinium-4-yl)porphyrin (ZnTMPyP ) sensitization of a series of polyoxometalate catalysts (two Dawson type, P Mo O and P W O anions, and one Keplerate {Mo } cluster) in a visible-light-driven, noble-metal-free, and fully water-soluble system. We attributed the high efficiency for hydrogen evolution to the multi-electron reduction of polyoxometalates and found that: (a) both Dawson polyoxometalates exhibit higher hydrogen evolution efficiency upon ZnTMPyP sensitization in relation to the direct photoreduction of those compounds; (b) the P Mo O anion is more efficient (TON=65 vs. 38, respectively) for hydrogen evolution than the P W O anion; and (c) the high nuclearity Keplerate {Mo } cluster exhibits the highest efficiency (TON=215) for hydrogen evolution compared with the polyoxometalates studied.

The purposes of this study were to assess the occurrence of euthyroid sick syndrome in patients with acute myocardial infarction (AMI) or unstable angina (UA), and the relationship with beta-blocker or thrombolytic therapy. Plasma triiodothyronine (T3), reverse T3 (rT3), free T3 (FT3), thyroxine (T4), free T4 (FT4), thyroid-stimulating hormone (TSH), thyroxine-binding globulin (TBG), and albumin (ALB) levels were determined in 95 patients (59 males, 36 females, aged 58.4+/-9) with AMI and 19 patients (13 males, 6 females aged 54.7+/-12.3) with UA for 5 consecutive days from the onset of the acute syndrome and 1 month later. Patients were divided according to beta-blocker therapy and thrombolytic therapy. There was a significant T3 decrease and rT3 increase in all patients during the first 5 days following admission (p < 0.05). FT3 and FT4 remained unchanged during the study. In patients with complicated infarctions, the rT3 increase and the T3 decrease were significantly greater compared to those with uncomplicated infarctions (p<0.03). TSH, T4, TBG, and ALB were significantly (p<0.05) decreased only in complicated infarctions. No differences were observed between patients with or without thrombolysis or patients with or without beta-blocker treatment. The apparent decrease in T3, the increase in rT3 levels and the decreased TSH and T4 levels, show clearly that the euthyroid sick syndrome (low T3) occurs not only in AMI but also in UA. In addition, these hormonal changes are not affected by beta-blocker therapy and thrombolysis does not influence the occurrence of the syndrome. The degree of T3 decrease is proportional to the severity of cardiac damage and may have a possible prognostic value.