[1] In 5 recent years (2000)(2001)(2002)(2003)(2004), the Changjiang (Yangtze) River has discharged past Datong (600 km from the river mouth) an average of $250 million tons (mt) of sediment per year, a decrease of more than 40% since the 1950s and 1960s, whereas water discharge at Datong has increased slightly. Water and sediment discharge data from the upper, middle, and lower reaches of the river suggest that the reduction of the Changjiang sediment load has occurred in two phases between 1950 From the sediment budget and sediment erosion data for the Changjiang subaqueous delta, it can be assumed that the delta will be eroded extensively during the first five decades after TGD operation and then will approach a balance during the next five decades as sediment discharging from TGD again increases.

The chemical and isotopic characteristics of the water and suspended particulate materials (SFM) in the Yangtze River were investigated on the samples collected from 25 hydrological monitoring stations in the mainsteam and 13 hydrological monitoring stations in the major tributaries during 2003 to 2007. The water samples show a large variation in both δD (‐30‰ to ‐112‰) and δ18O (‐3.8%. to ‐15.4‰) values. Both δD and δ18O values show a decrease from the river head to the Jinsha Jiang section and then increase downstream to the river mouth. It is found that the oxygen and hydrogen isotopic compositions of the Yangtze water are controlled by meteoric precipitation, evaporation, ice (and snow) melting and dam building. The Yangtze SPM concentrations show a large variation and are well corresponded to the spatial and temporal changes of flow speed, runoff and SPM supply, which are affected by the slope of the river bed, local precipitation rate, weathering intensity, erosion condition and anthropogenic activity. The Yangtze SPM consists of clay minerals, clastic silicate and carbonate minerals, heavy minerals, iron hydroxide and organic compounds. From the upper to lower reaches, the clay and clastic silicate components in SPM increase gradually, but the carbonate components decrease gradually, which may reflect changes of climate and weathering intensity in the drainage area. Compared to those of the upper crust rocks, the Yangtze SPM has lower contents of SiO2, CaO, K2O and Na2O and higher contents of TFe2O3 and trace metals of Co, Ni, Cu, Zn, Pb and Cd. The LREE in the Yangtze SPM is also slightly higher than that of the upper crust From the upper to lower reaches, the CaO and MgO contents in SPM decrease gradually, but the SiOz content increases gradually, corresponding to the increase of clay minerals and decrease of the carbonates. The δ30SiSPM values (‐1.1‰ to 0.3‰) of the Yangtze SPM are similar to those of the average shale, but lower than those of the granite rocks (‐0.3‰ to 0.3‰), reflecting the effect of silicon isotope fractionation in silicate weathering process. The δ30Sispm values of the Yangtze SPM show a decreasing trend from the upper to the middle and lower reaches, responding to the variation of the clay content. The major anions of the river water are HCO3–, SO42–, Cl–, NO3–, SiO44–and F– and the major cations include Ca2+, Na+, Mg2+, K+ and Sr2+. The good correlation between HCO3– content and the content of Ca2+ may suggest that carbonate dissolution is the dominate contributor to the total dissolved solid (TDS) of the Yangtze River. Very good correlations are also found among contents of Cl–, SO42–, Na+, Mg2+, K+ and Sr2+, indicating the important contribution of evaporite dissolution to the TDS of the Yangtze River. High TDS contents are generally found in the head water, reflecting a strong effect of evaporation in the Qinghai‐Tibet Plateau. A small increase of the TDS is generally observed in the river mouth, indicating the influence of tidal intrusion. The F– and NO3– contents show a clear increase trend from the upstream to downstream, reflecting the contribution of pesticides and fertilizers in the Chuan Jiang section and the middle and lower reaches. The Dsi shows a decrease trend from the upstream to downstream, reflecting the effect of rice and grass growth along the Chuan Jiang section and the middle and lower reaches. The dissolved Cu, Zn and Cd in the Yangtze water are all higher than those in world large rivers, reflecting the effect of intensive mining activity along the Yangtze drainage area. The Yangtze water generally shows similar REE distribution pattern to the global shale. The δ30SiDiss values of the dissolved silicon vary from 0.5‰ to 3.7‰, which is the highest among those of the rivers studied. The δ30SiDiss values of the water in the Yangtze mainsteam show an increase trend from the upper stream to downstream. Its DSi and δ30SiDiss are influenced by multiple processes, such as weathering process, phytolith growth in plants, evaporation, phytolith dissolution, growth of fresh water diatom, adsorption and desorption of aqueous monosilicic acid on iron oxide, precipitation of silcretes and formation of clays coatings in aquifers, and human activity. The (δ34SSO4 values of the Yangtze water range from ‐1.7‰ to 9.0‰. The SO4 in the Yangtze water are mainly from the SO4 in meteoric water, the dissolved sulfate from evaporite, and oxidation of sulfide in rocks, coal and ore deposits. The sulfate reduction and precipitation process can also affect the sulfur isotope composition of the Yangtze water. The 87Sr/86Sr ratios of the Yangtze water range from 0.70823 to 0.71590, with an average value of 0.71084. The 87Sr/86Sr ratio and Sr concentration are primary controlled by mixing of various sources with different 87Sr/86Sr ratios and Sr contents, including the limestone, evaporite and the silicate rocks. The atmospheric precipitation and anthropogenic inputs can also contribute some Sr to the river. The δ11B values of the dissolved B in the Yangtze water range from 2.0‰ to 18.3‰, which is affected by multifactors, such as silicate weathering, carbonate weathering, evaporite dissolution, atmospheric deposition, and anthropogenic inputs.

Th cells are the major effector cells in transplant rejection and can be divided into Th1, Th2, Th17, and Treg subsets. Th differentiation is controlled by transcription factor expression, which is driven by positive and negative cytokine and chemokine stimuli at the time of T cell activation. Here we discovered that chemokine platelet factor 4 (PF4) is a negative regulator of Th17 differentiation. PF4-deficient and platelet-deficient mice had exaggerated immune responses to cardiac transplantation, including increased numbers of infiltrating Th17 cells and increased plasma IL-17. Although PF4 has been described as a platelet-specific molecule, we found that activated T cells also express PF4. Furthermore, bone marrow transplantation experiments revealed that T cell-derived PF4 contributes to a restriction in Th17 differentiation. Taken together, the results of this study demonstrate that PF4 is a key regulator of Th cell development that is necessary to limit Th17 differentiation. These data likely will impact our understanding of platelet-dependent regulation of T cell development, which is important in many diseases, in addition to transplantation.

Abstract. To quantify the total, direct and indirect impacts of fireworks individually, size-resolved PM samples were collected before, during and after a Chinese folk festival (Chinese New Year) in a megacity in China. Through chemical analysis and morphological characterisation, a strong influence of fireworks on the physicochemical characteristics of PM 10 and PM 2.5 was observed. The concentrations of many species exhibited an increasing trend during the heavy-firework period, especially for K + , Mg 2+ and Cr; the results of the non-sea-salt ions demonstrated an anthropogenic influence on K + and Mg 2+ . Then, source apportionment was conducted by receptor models and peak analysis (PA). The total influence of the fireworks was quantified by positive matrix factorisation (PMF), showing that the fireworks contributed higher fractions (23.40 % for PM 10 and 29.66 % for PM 2.5 ) during the heavy-firework period than during the light-firework period (4.28 % for PM 10 and 7.18 % for PM 2.5 ). The profiles of the total fireworks obtained by two independent methods (PMF and peak analysis) were consistent, with higher abundances of K + , Al, Si, Ca and organic carbon (OC). Finally, the individual contributions of the direct and indirect impacts of fireworks were quantified by chemical mass balance (CMB). The percentage contributions of resuspended dust, biomass combustion and direct fireworks were 36.8 ± 8.37 %, 14.1 ± 2.82 % and 44.4 ± 8.26 %, respectively, for PM 10 and 34.9 ± 4.19 %, 16.6 ± 3.05 % and 52.5 ± 9.69 %, respectively, for PM 2.5 , in terms of the total fireworks. The quantification of the total, direct and indirect impacts of fireworks in the ambient PM gives a original contribution for understanding the physicochemical characteristics and mechanisms of such high-intensity anthropogenic activities.

Key Points• PF4 mediates VSMC injury responses.• PF4-driven effects are, in part, KLF4 dependent.Activated platelets release many inflammatory molecules with important roles in accelerating vascular inflammation. Much is known about platelet and platelet-derived mediator interactions with endothelial cells and leukocytes, but few studies have examined the effects of platelets on components of the vascular wall. Vascular smooth muscle cells (VSMCs) undergo phenotypic changes in response to injury including the production of inflammatory molecules, cell proliferation, cell migration, and a decline in the expression of differentiation markers. In this study, we demonstrate that the platelet-derived chemokine platelet factor 4 (PF4/CXCL4) stimulates VSMC injury responses both in vitro and in vivo in a mouse carotid ligation model. PF4 drives a VSMC inflammatory phenotype including a decline in differentiation markers, increased cytokine production, and cell proliferation. We also demonstrate that PF4 effects are mediated, in part, through increased expression of the transcription factor Krüppel-like factor 4. Our data indicate an important mechanistic role for platelets and PF4 in VSMC injury responses both in vitro and in vivo. (Blood. 2013;121(21):4417-4427)