Size Effect of Platinum Nanoparticles over Platinum-Manganese Oxide on the Low-Temperature Oxidation of Toluene.

The effect of size of Pt nanoparticles has an important influence on the performance of supported Pt-based catalysts for the elimination of toluene. Herein, uniform Pt nanoparticles with average sizes of 1.5, 2.0, 2.5, 2.9, and 3.6 nm were obtained and supported on manganese oxide octahedral molecular sieves (OMS-2), and their catalytic performances for toluene oxidation were evaluated. Benefiting from the moderate interfacial interaction between nanoparticles and manganese oxide support, Pt/OMS-2-3 with the Pt particle size of 3.0 nm showed the best catalytic performance owing to the highest content of Pt2+ species. It also facilitates the formation of more abundant Mnδ+ (Mn2+ and Mn3+) and oxygen vacancies than that of the other sizes of the OMS-2-supported Pt nanoparticles, which can be filled by a large amount of adsorbed oxygen and converted into reactive oxygen species. We further showed that the resulting surface synergetic oxygen vacancies (Pt2+-Ov-Mnδ+) play a decisive part in catalyzing the complete oxidation of toluene. The result will provide new insights for designing efficient Pt-based catalysts for deep purification of toluene.

Metabolite target analysis of human urine combined with pattern recognition techniques for the study of symptomatic gout.

Recurrent attacks and irregularity are two important characteristics of gout disease. Uric acid as a single evaluation indicator for clinical diagnosis is insufficient considering the versatile properties of gout. The aim of this work is to identify several endogenous metabolites from urine samples for the elucidation and prediction of gout disease. Metabolite target analysis was established for human urine by high performance liquid chromatography-diode array detection (HPLC-DAD). The targeted metabolites selected included hippuric acid, uracil, phenylalanine, tryptophan, uric acid and creatinine as well as nine purine compounds. Useful information was extracted from multivariate data through Fisher Linear Discriminant Analysis (FDA) and Orthogonal Signal Correction Partial Least Squares Discriminant Analysis (OSC-PLS-DA). Uric acid, hypoxanthine, xanthosine, guanosine, inosine and tryptophan were identified as important metabolites among the acute and chronic gout and controls. Based on OSC-PLS-DA models, the regression equations obtained could discriminate gout from the controls as well as the acute from chronic. The recognition and prediction ability is respectively 100% and 85.0% for the gout, 100% and 83.3% for the acute, and 90.91% and 89.9% for the chronic. Metabolic dysfunction of tryptophan and excessive metabolism of xanthosine and hypoxanthine to xanthine were confirmed for gout disease. Metabolic dysfunction of tryptophan was also proven to be induced by allopurinol in case of Kunming mice with hyperuricemia. Potential biomarkers can be used not only to distinguish gout patients from healthy people, but also to evaluate the disease state.

Block copolymer micellization induced microphase mass transfer: partition of Pd(II), Pt(IV) and Rh(III) in three-liquid-phase systems of S201-EOPO-Na2SO4-H2O.

Three-liquid-phase partitioning of Pd(II), Pt(IV) and Rh(III) in systems of S201(diisoamyl sulfide)/nonane-EOPO(polyethylene oxide-polypropylene oxide random block copolymer)-Na(2)SO(4)-H(2)O was investigated. Experimental results indicated that the selective enrichment of Pd(II), Pt(IV) and Rh(III) respectively into the S201 organic top phase, EOPO-based middle phase and Na(2)SO(4) bottom phase was achieved by control over the phase behavior of the three-liquid-phase systems (TLPS). The microphase mass transfer behavior of Pt(IV), Pd(II) and Rh(III) was closely related to the micellization of EOPO molecules. A suggested micro-mechanism model and a mass transfer model describe the micellization of EOPO molecules and the effect on mass transfer of platinum ions across the microphase interfaces. The salting-out induced continuous dehydration and ordered arrangement of the hydrophilic PEO segments in amphiphilic EOPO micelle, and these are the main driving forces for mass transfer of platinum metal ions onto the exposed activity sites of the dehydrated PEO segments. The differences in microphase interfacial structure of EOPO micelles are crucial for the efficient separation between Pt(IV), Pd(II) and Rh(III).