Cyano modified triphenylmethyl radical skeletons: higher stability and efficiency.

We introduced cyano groups to replace chlorine atoms in the tris(2,4,6-trichlorophenyl)methyl (TTM) radical skeleton, resulting in two cyano-modified TTM skeletons. The incorporation of cyano groups effectively suppresses nonradiative transition processes and lowers the frontier molecular orbital energy levels compared to those of the TTM radical. Consequently, enhanced photoluminescence quantum efficiency (PLQE) and a shift towards longer-wavelength emission in solution were achieved. Furthermore, the cyano-modified TTM skeletons exhibited improved stabilities. The development of these two skeletons adds diversity to stable organic luminescent radical skeletons.

Driving factors of phytoplankton functional groups in the shallow eutrophic lakes of lowland areas of Huaihe River (China).

In this study, we want to clarify the driving factors of phytoplankton community in a set of eutrophic lakes in the lowland areas of Huaihe River, one of seven biggest rivers in China. We analyzed the phytoplankton community of five lakes located in the lowland areas of Huaihe River using Reynolds functional groups (RFG) approach, with simultaneous measurement of several environmental variables in monthly sampling campaigns during 2 years. The annual average phytoplankton biovolume of the five lakes ranged from 3.7 to 9.9 mm3/L, with the highest values occurring during warm seasons. The shallow eutrophic lakes primarily contained mixing and low-light adaptive species with C and D groups as dominant all-round the year. Representatives of X2, Y, and W1 were predominant during the spring and the autumn with high nutrients and organic matter concentrations. Cyanobacteria were mainly represented by group S1 especially during the summer. Mixing, temperature, together weak light caused by phytoplankton biomass, could shape phytoplankton assemblage more than nutrients in the shallow eutrophic lakes with warm-temperate climate.

Distribution and adsorption of metals on different particle size fractions of sediments in a hydrodynamically disturbed canal.

Sediment resuspension widely occurs in environments with hydrodynamic disturbances, where particles are sieved into different grain size groups. The particles of different grain size exhibit heterogeneity of their physical, chemical or biological features. This research addressed the association of metals on size fractional particles sieved by sediment resuspension in a canal of Taihu basin, a highly urbanized and human-impacted area. Surface sediment samples were collected from upstream to downstream sections of the canal to analyze the concentrations and fractionation of lead (Pb), zinc (Zn), and copper (Cu). One sediment sample was sieved into five different particle size groups (50-150 µm, 30-50 µm, 10-30 µm, 5-10 µm and <5 µm) through the wet sedimentation method. The strong adsorption ability of metals on fine particles is attributed to enrichment with organic matter and iron/aluminum (Fe/Al) oxides, with the increase in Pb, Zn, and Cu concentrations from 34.2 mg/kg, 263 mg/kg, and 32.5 mg/kg of 50-150 µm size group particles to 71.4 mg/kg, 698 mg/kg, and 137 mg/kg of <5 µm size group particles, respectively. The fine particles showed stronger sorption ability on Pb than Zn and Cu, with the Freundlich isotherm constant (Kf) values of the adsorption isotherms in the <10 µm size particle group ranging from 3.7 to 5.9 g/kg for Zn and Cu versus from 11 to 18 g/kg for Pb, probably causing difference on metals accumulation and releasing risk among metals in the downstream lakes with changeable environments.