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We performed incubation experiments using seawaters from representative marine environments of the eastern Asian seas to determine the mercury (Hg) available for photoreduction (Hgr(II)), to investigate the Hg redox reaction kinetics, and to explore the effect of environmental factors and water chemistry on the Hg redox chemistry. Results show that Hgr(II) accounted for a considerable fraction of total Hg (THg) (%Hgr(II)/THg: 24.90 ± 10.55%, n = 27) and positively correlated with THg. Filtration decreased the Hgr(II) pool of waters with high suspended particulate matter (SPM). The positive linear relationships were found between pseudo-first order rate constants of gross Hg(II) photoreduction (kr) and gross Hg(0) photo-oxidation (ko) with photosynthetically active radiation (PAR). Under the condition of PAR of 1 m mol m-2 s-1, the kr were significantly (p < 0.05) lower than ko (kr/ko: 0.86 ± 0.22). The Hg(0) dark oxidation were significantly higher than the Hg(II) dark reduction. The Hg(II) dark reduction was positively correlated to THg, and the anaerobic condition favored the Hg(II) dark reduction. Filtration significantly influenced the Hg photoredox chemistry of waters with high SPM. UVB radiation was important for both Hg(II) photoreduction and Hg(0) photo-oxidation, and the role of other wavebands in photoinduced transformations of Hg varied with the water chemistry. [ABSTRACT FROM AUTHOR]

The article focuses on the significance of improving the field of atmospheric mercury (Hg) research in China to enhance the knowledge about the global Hg cycle. It discusses the adverse health effects brought by the exposure to Hg, which predominantly exists in gaseous form, in both humans and wildlife. It says that China has played an important role in the protection of human health and ecosystems such as the development of renewable energies, afforestation, and strict pollutant emission standards. It suggests the importance of the development of a framework for understanding data and effective strategies for the priority in research to lessen uncertainties of Hg in the country.

Artemis, a member of the SNM1 gene family, is a known phosphorylation target of ATM, ATR, and DNA-PKcs. We have previously identified two serine residues in Artemis (Ser[sup516] and Ser[sup645]) that are subject to phosphorylation by ATM and are involved in mediating recovery from the G[sub2]/M checkpoint in response to ionizing radiation. Here we show that these same sites are also phosphorylated by ATR in response to various types of replication stress including UVC, aphidicolin, and hydroxyurea. We also show that mutation of the Ser[sup516] and Ser[sup645] residues causes a prolonged S phase checkpoint recovery after treatment with UV or aphidicolin, and that this delayed recovery process coincides with a prolonged stabilization of cyclin E and down-regulation of Cdk2 kinase activity. Furthermore, we show that Artemis interacts with the F-box protein Fbw7, and that this interaction regulates cyclin E degradation through the SCF[supFbW7] E3 ubiquitin ligase complex. The interaction between Artemis and Fbw7 is regulated by phosphorylation of Ser[sup516] and Ser[sup645] sites that occur in response to replication stress. Thus, our findings suggest a novel pathway of recovery from the S phase checkpoint in that in response to replication stress phosphorylation of Artemis by ATR enhances its interaction with Fbw7, which in turn promotes ubiquitylation and the ultimate degradation of cyclin E. [ABSTRACT FROM AUTHOR]

Mutations in Artemis in both humans and mice result in severe combined immunodeficiency due to a defect in V(D)J recombination. In addition, Artemis mutants are radiosensitive and chromosomally unstable, which has been attributed to a defect in nonhomologous end joining (NHEJ). We show here, however, that Artemisdepleted cell extracts are not defective in NHEJ and that Artemis-deficient cells have normal repair kinetics of double-strand breaks after exposure to ionizing radiation (IR). Artemis is shown, however, to interact with known cell cycle checkpoint proteins and to be a phosphorylation target of the checkpoint kinase ATM or ATR after exposure of cells to IR or UV irradiation, respectively. Consistent with these findings, our results also show that Artemis is required for the maintenance of a normal DNA damage-induced G2/M cell cycle arrest. Artemis does not appear, however, to act either upstream or downstream of checkpoint kinase Chk1 or Chk2. These results define Artemis as having a checkpoint function and suggest that the radiosensitivity and chromosomal instability of Artemis-deficient cells may be due to defects in cell cycle responses after DNA damage. [ABSTRACT FROM AUTHOR]

We report on the speciation of sulfate, nitrate with special attention to their ammonium salts during 1999–2000 in Beijing. Higher concentrations in fine particles were observed for ammonium sulfate and other sulfates during winter. Ammonium sulfate concentration ranged from 2.78 to 23.7 μg m−3 in fine particles, and ranged from 0.15 to 1.39 μg m−3 in coarse particles. Other sulfate concentrations ranged from 1.51 to 11.9 μg m−3 in fine particles, and ranged from 0.10 to 1.00 μg m−3 in coarse particles. Ammonium nitrate was mainly in fine particles with the highest concentration in December (11.9 μg m−3). Other nitrates were mainly distributed in the particles of 2.1–4.7 μm with concentrations ranged between 0.36 and 2.54 μg m−3, and the highest concentration of other nitrates was observed in fine particles in January (9.32 μg m−3). XRD analysis showed that ammonium sulfates existed in different forms in atmospheric aerosols. The results suggested the importance of heterogeneous formations of sulfate and nitrate in Beijing especially in winter. [Copyright &y& Elsevier]

Artemis is a phospho-protein that has been shown to have roles in V(D)J recombination, nonhomologous end-joining of double-strand breaks, and regulation of the DNA damage-induced G2/M cell cycle checkpoint. Here, we have identified four sites in Artemis that are phosphorylated in response to ionizing radiation (IR) and show that ATM is the major kinase responsible for these modifications. Two of the sites, S534 and S538, show rapid phosphorylation and dephosphorylation, and the other two sites, S516 and S645, exhibit rapid and prolonged phosphorylation. Mutation of both of these latter two residues results in defective recovery from the G2/M cell cycle checkpoint. This defective recovery is due to promotion by mutant Artemis of an enhanced interaction between unphosphorylated cyclin B and Cdk1, which in turn promotes inhibitory phosphorylation of Cdk1 by the Wee1 kinase. In addition, we show that mutant Artemis prevents Cdk1-cyclin B activation by causing its retention in the centrosome and inhibition of its nuclear import during prophase. These findings show that ATM regulates G2/M checkpoint recovery through inhibitory phosphorylations of Artemis that occur soon after DNA damage, thus setting a molecular switch that, hours later upon completion of DNA repair, allows activation of the Cdk1-cyclin B complex. These findings thus establish a novel function of Artemis as a regulator of the cell cycle in response to DNA damage. [ABSTRACT FROM AUTHOR]

Mercury (Hg) emission from coal combustion in China is estimated in this study and its deposition calculated using the Models-3 Community Multi-scale Air Quality (CMAQ-Hg) modeling system with meteorological fields calculated by MM5. Three kinds of Hg speciation were included in the models: particle-bound Mercury (PHg), gaseous elemental Mercury (GEM) and gas oxidized Mercury (RGM). Much of the Hg was released as RGM from coal combustion in China, accounting for 58.4 - 66.8% of total emissions. The large proportion of RGM in overall Hg emission also led to large Hg deposition. Based on simulations, Hg deposition originating from coal combustion reaches as high as 2 - 6 µg m-2 month-1 in south western China (particularly Guizhou Province), the industrialized and populated regions of east central and coastal China, and Liaoning Province in the northeast. [ABSTRACT FROM AUTHOR]

Airborne particulate pollution is a critical environmental problem affecting human health and sustainable development. Understanding of the sources of aerosol particles is of extreme importance for regional air pollution control. Here we show that natural Si isotopic signature can be used as a new tool to elucidate the sources of fine particulate matter (PM2.5). Through the analysis of Si isotopic composition (δ30Si) of PM2.5 and its primary sources collected in a typical pollution region – Beijing, we recognized the direct source tracing ability of Si isotopes for PM2.5. The different primary sources of PM2.5 had different Si isotopic signatures. The δ30Si value of PM2.5 ranged from −1.99‰ to −0.01‰ and showed a distinct seasonal trend (isotopically lighter in spring/winter and heavier in summer/autumn). The variations in δ30Si of PM2.5 revealed that Si-isotopically light sources were important sources for Beijing's severe haze pollution and that coal burning was a major cause for the aggregating haze weather in spring/winter in Beijing. We also analyzed several typical haze events by using Si isotopic signatures. As the first study on the natural Si isotopes in the atmospheric environment, this study may reveal an important tool to advance the particulate pollution research and control. [ABSTRACT FROM AUTHOR]

Fieldlike spin-orbit torque in FeMn/Pt bilayers with ultrathin polycrystalline FeMn has been characterized through planar Hall effect measurements. A large effective field of 2.05?10-5 to 2.44?10-5Oe(A-1cm2) is obtained for FeMn in the thickness range of 2-5 nm. The experimental observations can be reasonably accounted for by using a macrospin model under the assumption that the FeMn layer is composed of two spin sublattices with unequal magnetizations. The large effective field corroborates the spin Hall origin of the effective field, considering the much smaller uncompensated net moments in FeMn as compared to NiFe. The effective absorption of spin current by FeMn is further confirmed by the fact that spin current generated by Pt in NiFe/FeMn/Pt trilayers can only travel through the FeMn layer with a thickness of 1-4 nm. By quantifying the fieldlike effective field induced in NiFe, a spin diffusion length of 2 nm is estimated in FeMn, consistent with values reported in the literature by ferromagnetic resonance and spin-pumping experiments. [ABSTRACT FROM AUTHOR]

We fabricated epitaxial exchange biased (EB) IrMn/FeGa bilayers by oblique deposition and systematically investigated their magnetization reversal. Two different configurations with the uniaxial magnetic anisotropy Ku parallel and perpendicular to the unidirectional anisotropy Keb were obtained by controlling the orientation of the incident FeGa beam during deposition. A large ratio of Ku/Keb was obtained by obliquely depositing the FeGa layer to achieve a large Ku while reducing the IrMn thickness to obtain a small Keb. Besides the previously reported square loops, conventional asymmetrically shaped loops, and one-sided and two-sided two-step loops, unusual asymmetrically shaped loops with a three-step magnetic transition for the descending branch and a two-step transition for the ascending branch and biased three-step loops were observed at various field orientations in the films of both IrMn (tIrMn=1.5 to 20 nm)/FeGa (10 nm) with Ku⊥ Keb and IrMn (tIrmn≤=2 nm)/FeGa (10 nm) with Ku// Keb. Considering the geometries of anisotropies, a model based on domain wall nucleation and propagation was employed to quantitatively describe the angular dependent behaviors of IrMn/FeGa bilayers. The biased three-step magnetic switching was predicted to take place when /Ku/> ε90°+Keb, where ε90° is the 90° domain wall nucleation energy, and the EB leads to the appearance of the unusual asymmetrically shaped hysteresis loops. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric poly(vinylidene fluoride) (PVDF) based terpolymers are attracting tremendous interest because of their potential applications in advanced energy harvesting and storage devices. Fundamental understanding of the ferroelectric behaviors of hysteresis loops results from physical pinning of the ferroelectric domains by the bulky defect monomers and that the size of the defect monomer determines the ferroelectric behavior. In this study, a poly(vinylidene fluoride-ter-trifluoroethyleneter- chlorotrifluoroethylene) random terpolymer is processed using a variety of methods and found to exhibit normal ferroelectric, single hysteresis loop (SHL), and double hysteresis loop (DHL) behaviors depending on the processing method. This indicates that the ferroelectric behavior of the terpolymer is related to not only the size of an individual defect unit but also how they are arranged within the relaxor ferroelectric phase. The results show that DHL behavior is a result of paraelectric domains that are promoted by long crystallization times, while the SHL behavior stems from a more random dispersion of these defects. [ABSTRACT FROM AUTHOR]

Magnetostrictive FeGa thin films were deposited on the bowed flexible polyethylene terephthalate (PET) substrates, which were fixed on the convex mold. A compressive stress was induced in FeGa films when the PET substrates were shaped from convex to flat. Due to the effect of magnetostriction, FeGa films exhibit an obvious in-plane uniaxial magnetic anisotropy which could be enhanced by increasing the applied pre-strains on the substrates during growth. Consequently, the ferromagnetic resonance frequency of the films was significantly increased, but the corresponding initial permeability was decreased. Moreover, the films with pre-strains less than 0.78% exhibit a working bandwidth of microwave absorption about 2GHz. Our investigations demonstrated a convenient method via the prestrained substrates to tune the high frequency properties of magnetic thin films which could be applied in flexible microwave devices. [ABSTRACT FROM AUTHOR]

Thermal and electrical control of magnetic anisotropy were investigated in flexible Fe81Ga19 (FeGa)/Polyvinylidene fluoride (PVDF) multiferroic heterostructures. Due to the large anisotropic thermal deformation of PVDF (α1 = −13 × 10−6 K−1 and α2 = −145 × 10−6 K−1), the in-plane uniaxial magnetic anisotropy (UMA) of FeGa can be reoriented 90° by changing the temperature across 295 K where the films are magnetically isotropic. Thus, the magnetization of FeGa can be reversed by the thermal cycling between 280 and 320 K under a constant magnetic field lower than coercivity. Moreover, under the assistance of thermal deformation with slightly heating the samples to the critical temperature, the electric field of ± 267 kV cm−1 can well align the UMA along the two orthogonal directions. The new route of combining thermal and electrical control of magnetic properties realized in PVDF-based flexible multiferroic materials shows good prospects in application of flexible thermal spintronic devices and flexible microwave magnetic materials. [ABSTRACT FROM AUTHOR]

The magnetic anisotropy is decreased with increasing temperature in normal magnetic materials, which is harmful to the thermal stability of magnetic devices. Here, we report the realization of positive temperature coefficient of magnetic anisotropy in a novel composite combining β-phase polyvinylidene fluoride (PVDF) with magnetostrictive materials (magnetostrictive film/PVDF bilayer structure). We ascribe the enhanced magnetic anisotropy of the magnetic film at elevated temperature to the strain-induced anisotropy resulting from the anisotropic thermal expansion of the β-phase PVDF. The simulation based on modified Stoner-Wohlfarth model and the ferromagnetic resonance measurements confirms our results. The positive temperature coefficient of magnetic anisotropy is estimated to be 1.1 × 102 J m-3 K-1. Preparing the composite at low temperature can enlarge the temperature range where it shows the positive temperature coefficient of magnetic anisotropy. The present results may help to design magnetic devices with improved thermal stability and enhanced performance. [ABSTRACT FROM AUTHOR]

To determine prevalence of Cyclospora cayetanensis infection in Henan, China, we conducted a study of 11,554 hospital patients. Prevalence was 0.70% (95% confidence interval 0.70% ± 0.15%), with all age groups infected. Most cases were found in the summer. Minor sequence polymorphisms were observed in the 18S rRNA gene of 35 isolates characterized. [ABSTRACT FROM AUTHOR]

The article presents information related to the problem of acid rain in China. It has become an important environmental problem, which is caused as a result of significant emissions and subsequent deposition of sulfur in the atmosphere. It can lead to acidification of surface waters and soils. The extensive use of coal is the major cause of acid rain in China. The rate of increase is currently faster than ever. Several Chinese cities have high concentrations of particulates and sulphur dioxide in the air. The impact of air pollution on the natural environment may have a different geographical distribution than the impacts on human health. It is found that alkaline dust from the desert areas largely neutralizes the acids in the deposition in Northern China. In order to tackle with issue, national monitoring programs are being implemented in China, which generally focus on urban air quality and precipitation pH. Further, calcium and magnesium are believed to play an important role in modifying aluminum toxicity, which in turn helps in reduction of environmental hazards.

Spindle poisons represent an important class of anticancer drugs that act by interfering with microtubule polymerization and dynamics and thereby induce mitotic checkpoints and apoptosis. Here we show that mammalian SNM1 functions in an early mitotic stress checkpoint that is distinct from the well-characterized spindle checkpoint that regulates the metaphase-to-anaphase transition. Specifically, we found that compared to wild-type cells, Snm1-deficient mouse embryonic fibroblasts exposed to spindle poisons exhibited elevated levels of micronucleus formation, decreased mitotic delay, a failure to arrest in mitosis prior to chromosome condensation, supernumerary centrosomes, and decreased viability. In addition, we show that both Snm1 and 53BP1, previously shown to interact, coimmunoprecipitate with components of the anaphase-promoting complex (APC)/cyclosome. These findings suggest that Snm1 is a component of a mitotic stress checkpoint that negatively targets the APC prior to chromosome condensation. [ABSTRACT FROM AUTHOR]