Ordered-Porous-Array Polymethyl Methacrylate Films for Radiative Cooling.

Passive radiative cooling is a spontaneous pattern of reflecting sunlight and radiating heat into the cold outer space through transparent atmosphere windows. In this work, an ordered-porous-array polymethyl methacrylate (OPA-PMMA) film with the properties of excellent radiative cooling is designed and studied. An ultra-high emissivity of 98.4% in the mid-infrared region (3-25 µm) and a good solar reflectance of 85% in the ultraviolet and near-infrared solar spectra (0.2-2.5 µm) were achieved. The surface temperature of the OPA-PMMA film is 16 °C lower than that of the smooth-surface PMMA films and is 8.6 °C lower than that of the commercial white paint in the outdoor test. The structure of the OPA plays an important role in improving solar reflectivity and emissivity. The films are fabricated using a one-step low-cost process that can be applied for large-scale production. It is vital for promoting radiative cooling as a viable energy technology for buildings, fabric, or equipment that need a cooling environment.

Formation of novel disinfection by-products chlorinated benzoquinone, phenyl benzoquinones and polycyclic aromatic hydrocarbons during chlorination treatment on UV filter 2,4-dihydroxybenzophenone in swimming pool water.

2,4-Dihydroxybenzophenone (BP-1) is an important component and metabolite of benzophenone-type (BPs) UV filters, it is widely used in commercial products and frequently detected in environmental media and organism samples. The transformation characteristics and genotoxicity changes of BP-1 during chlorination disinfection process were explored. Nineteen transformation products were separated and tentatively identified, eleven of which were not previously reported. Most importantly, nine novel by-products including one chlorobenzoquinone, four phenyl benzoquinones, and four polycyclic aromatic hydrocarbons were formed during BP-1 chlorination. Plausible transformation pathways for BP-1 during chlorination treatment were proposed, in which chlorination substitution, Baeyer-Villiger oxidation, hydrolysis, and CC coupling reactions were involved. The CC coupling reaction is firstly observed in chlorination disinfection system. Higher pH values and chlorine doses would be a benefit for BP-1 transformation. The genotoxicity of the reaction mixture increased significantly with increasing chlorine dose under acid and neutral conditions due to the formation of benzoquinones and polycyclic aromatic hydrocarbons. It was noted that BP-1 and its chlorinated products were found in swimming pool water samples. This work inferred that BP-1 and its analogs are transformed during the chlorination disinfection process and may cause potential ecological and health risks.

Synthesis and biological activities of petrosiols B and D.

A divergent total synthesis of natural diacetylenic tetraols, petrosiol B and petrosiol D, was accomplished by taking advantage of a carbohydrate chiral template. In particular, petrosiol B, which is the first total synthesis so far, was achieved in 13 linear steps with a 10% overall yield applying Ohira-Bestmann homologation, NaH-mediated dehydrobromination, and Cu(i)-catalyzed Cadiot-Chodkiewicz coupling as the key reaction steps. The synthetic petrosiols B and D were subjected to the study on differentiation activities toward neuronal progenitor PC12 cells. Our results suggested that both petrosiol B and petrosiol D could induce the differentiation of neuronal progenitor PC12 cells via the enhancement of Nrf2 activity. By comparing petrosiols B, D and their natural homologue E, petrosiol B displayed the most intensive cell differentiation activity and the highest Nrf2 activity enhancement as well.