Paleoproductivity evolution in the West Philippine Sea during the last 700 ka

In order to reconstruct the paleoproductivity evolution history of the West Philippine Sea during the last 700 ka,the vertical gradient of δ 13 C in dissolved inorganic carbon(δ 13 C between those of foraminifera Pulleniatina obliquiloculata and Cibicidoides wuellerstorfi) and planktonic foraminiferal assemblages were analysed in piston Core MD06-3047 retrieved from the Benham Rise(east of the Luzon Island).Paleoproductivity evolution in the West Philippine Sea during the last 700 ka is closely related to glacial-interglacial cycles and precession-controlled insolation.Controlling factors of paleoproductivity could have been both thermocline fluctuations related with ENSO-like processes and eolian input associated with East Asian winter monsoon,and the former could have been the primary factor.A higher productivity and a shallower thermocline coeval with the occurrence of low CO 2 concentrations in the EPICA Dome C ice core might indicate that biological export production in the low-latitude could act as a significant sink in the global carbon cycle,and modify atmospheric CO 2 concentrations.Spectral analysis further reveals that the paleoproductivity is mainly controlled by thermocline fluctuations subjected to ENSO processes responding to processional variability of insolation.High coherences in eccentricity,obliquity and precession periods further revealing the close link between thermocline fluctuations,paleoproductivity and atmospheric CO 2 levels.

The preparation and performance of visible-light-sensitized luminescent nanoparticles based on europium complex

Long-wavelength-sensitized luminescent materials are desired for bio-detection. In this paper, we prepared a new kind of luminescent europium nanoparticles by a co-precipitation-condensation method. The luminescent europium complex Eu（tta）3.bpt （tta = thenoyltrifluoroacetonate; bpt = 2-（N,N- di-ethylanilin-4-yl）-4,6-bis（pyrazol-l-yl）-l,3,5-triazine） was used as the active material, being encapsulated in the nanoparticles formed from 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane （PFOTS） and poly（styrene-co-methyl methacrylate） [P（ST-co-MMA）]. The prepared nanoparticles not only can be well dispersed in water but also were of high photostability. Importantly, the nanoparticles displayed maximal excitation wavelength at 425 nm as well as an extended excitation wavelength up to 480 nm and a quantum yield for Eu3＋ luminescence of 0.22 （λex= 425 nm, room temperature）.