Using Mercury Stable Isotopes to Quantify Directional Soil-Atmosphere Hg(0) Exchanges in Rice Paddy Ecosystems: Implications for Hg(0) Emissions to the Atmosphere from Land Surfaces.

Gaseous elemental mercury [Hg(0)] emissions from soils constitute a large fraction of global total Hg(0) emissions. Existing studies do not distinguish biotic- and abiotic-mediated emissions and focus only on photoreduction mediated emissions, resulting in an underestimation of soil Hg(0) emissions into the atmosphere. In this study, directional mercury (Hg) reduction pathways in paddy soils were identified using Hg isotopes. Results showed significantly different isotopic compositions of Hg(0) between those produced from photoreduction (δ202Hg = -0.80 ± 0.67‰, Δ199Hg = -0.38 ± 0.18‰), microbial reduction (δ202Hg = -2.18 ± 0.25‰, Δ199Hg = 0.29 ± 0.38‰), and abiotic dark reduction (δ202Hg = -2.31 ± 0.25‰, Δ199Hg = 0.50 ± 0.22‰). Hg(0) exchange fluxes between the atmosphere and the paddy soils were dominated by emissions, with the average flux ranging from 2.2 ± 5.7 to 16.8 ± 21.7 ng m-2 h-1 during different sampling periods. Using an isotopic signature-based ternary mixing model, we revealed that photoreduction is the most important contributor to Hg(0) emissions from paddy soils. Albeit lower, microbial and abiotic dark reduction contributed up to 36 ± 22 and 25 ± 15%, respectively, to Hg(0) emissions on the 110th day. These novel findings can help improve future estimation of soil Hg(0) emissions from rice paddy ecosystems, which involve complex biotic-, abiotic-, and photoreduction processes.

Mercury and Sulfur Redox Cycling Affect Methylmercury Levels in Rice Paddy Soils across a Contamination Gradient.

Methylmercury (MeHg) contamination in rice via paddy soils is an emerging global environmental issue. An understanding of mercury (Hg) transformation processes in paddy soils is urgently needed in order to control Hg contamination of human food and related health impacts. Sulfur (S)-regulated Hg transformation is one important process that controls Hg cycling in agricultural fields. In this study, Hg transformation processes, such as methylation, demethylation, oxidation, and reduction, and their responses to S input (sulfate and thiosulfate) in paddy soils with a Hg contamination gradient were elucidated simultaneously using a multi-compound-specific isotope labeling technique (200HgII, Me198Hg, and 202Hg0). In addition to HgII methylation and MeHg demethylation, this study revealed that microbially mediated reduction of HgII, methylation of Hg0, and oxidative demethylation-reduction of MeHg occurred under dark conditions; these processes served to transform Hg between different species (Hg0, HgII, and MeHg) in flooded paddy soils. Rapid redox recycling of Hg species contributed to Hg speciation resetting, which promoted the transformation between Hg0 and MeHg by generating bioavailable HgII for fuel methylation. Sulfur input also likely affected the microbial community structure and functional profile of HgII methylators and, therefore, influenced HgII methylation. The findings of this study contribute to our understanding of Hg transformation processes in paddy soils and provide much-needed knowledge for assessing Hg risks in hydrological fluctuation-regulated ecosystems.

Paddle Stroke Analysis for Kayakers Using Wearable Technologies.

Proper stroke posture and rhythm are crucial for kayakers to achieve perfect performance and avoid the occurrence of sport injuries. The traditional video-based analysis method has numerous limitations (e.g., site and occlusion). In this study, we propose a systematic approach for evaluating the training performance of kayakers based on the multiple sensors fusion technology. Kayakers' motion information is collected by miniature inertial sensor nodes attached on the body. The extend Kalman filter (EKF) method is used for data fusion and updating human posture. After sensor calibration, the kayakers' actions are reconstructed by rigid-body model. The quantitative kinematic analysis is carried out based on joint angles. Machine learning algorithms are used for differentiating the stroke cycle into different phases, including entry, pull, exit and recovery. The experiment shows that our method can provide comprehensive motion evaluation information under real on-water scenario, and the phase identification of kayaker's motions is up to 98% validated by videography method. The proposed approach can provide quantitative information for coaches and athletes, which can be used to improve the training effects.

Efficacy of porcine antihuman lymphocyte immunoglobulin compared to rabbit antithymocyte immunoglobulin as a first-line treatment against acquired severe aplastic anemia.

Immunosuppressive therapy (IST) with antithymocyte immunoglobulin (ATG) or antilymphocyte immunoglobulin (ALG) and cyclosporine A (CsA) is the treatment of choice against severe aplastic anemia (SAA) worldwide. However, a comparison of the efficacy of porcine ALG (pALG) and rabbit ATG (rATG) as a first-line treatment for acquired SAA has not been reported. In the present study, we retrospectively analyzed SAA patients treated with either pALG (n = 43) or rATG (n = 32) and compared their hematologic responses and survivals. There were no significant differences in overall response (OR) rates between pALG and rATG groups at 3 months (OR 41.86 versus 40.62% (P = 0.914), 6 months (OR 66.67 versus 61.29% (P = 0.635), 9 months (OR 69.05 versus 61.29% (P = 0.490), or 12 months (OR 69.05 versus 64.51% (P = 0.684), respectively. The OR rates in patients with SAA or very severe aplastic anemia (vSAA) in both groups were similar after a 12-month treatment (pALG 74.07 versus 60.00%, P = 0.550; rATG 70.00 versus 54.55%, P = 0.640). Patients who experienced <30-day interval between diagnosis and treatment displayed higher OR rates (at 12 months) than those with intervals ≥30 days (pALG 83.33 versus 50.00%, P = 0.021; rATG 87.50 versus 40.00%, P = 0.006). There were no significant differences in 2-year overall survival (OS) between pALG (87.4 ± 6.2%) and rATG (83.2 ± 7.8%) (P = 0.493). Infection was the major cause of death in both groups. In summary, pALG + CsA showed similar efficacy as rATG + CsA, as a first-line treatment for acquired SAA.

Warming inhibits HgII methylation but stimulates methylmercury demethylation in paddy soils.

Inorganic mercury (HgII) can be transformed into neurotoxic methylmercury (MeHg) by microorganisms in paddy soils, and the subsequent accumulation in rice grains poses an exposure risk for human health. Warming as an important manifestation of climate change, changes the composition and structure of microbial communities, and regulates the biogeochemical cycles of Hg in natural environments. However, the response of specific HgII methylation/demethylation to the changes in microbial communities caused by warming remain unclear. Here, nationwide sampling of rice paddy soils and a temperature-adjusted incubation experiment coupled with isotope labeling technique (202HgII and Me198Hg) were conducted to investigate the effects of temperature on HgII methylation, MeHg demethylation, and microbial mechanisms in paddy soils along Hg gradients. We showed that increasing temperature significantly inhibited HgII methylation but promoted MeHg demethylation. The reduction in the relative abundance of Hg-methylating microorganisms and increase in the relative abundance of MeHg-demethylating microorganisms are the likely reasons. Consequently, the net Hg methylation production potential in rice paddy soils was largely inhibited under the increasing temperature. Collectively, our findings offer insights into the decrease in net MeHg production potential associated with increasing temperature and highlight the need for further evaluation of climate change for its potential effect on Hg transformation in Hg-sensitive ecosystems.

[The immunomodulatory effect of neutrophil extracellular trapping nets (NETs) on hematological diseases].

Neutrophil extracellular traps (NETs) are characterized by a extracellular fibrous network structure produced by neutrophils with DNA and proteins. NETs can be formed by NADPH-dependent NETosis and NADPH-independent NETosis. After formation, it is not only hydrolyzed by DNase in plasma but can also be degraded intracellularly and extracellularly by macrophages and dendritic cells. Recent researches on NETs have reported the increased expression of NETs in a variety of hematological diseases and its immunomodulatory effect on blood system diseases. For example, NETs are closely linked to infections related to leukemia treatment, which affects the treatment and prognosis of leukemia; NETs are also involved in the progression of multiple myeloma, promote the progression of diffuse large B-cell lymphoma, and mediate the thrombotic events of chronic myeloproliferative tumors.

[Immuno-effect of plasmacytoid dendritic cells on bacteria infection induced spontaneous remission of leukemia].

OBJECTIVE: To explore the immuno-effect of plasmacytoid dendritic cells (pDC) on bacteria infection induced spontaneous remission (SR) of leukemia. METHODS: Both pDC and myeloid dendritic cells (mDC) were isolated and purified from leukemic patient with SR and healthy donor by combination of immunomagnetic beads and flow cytometry. pDC were cultured in RPMI1640 medium and stimulated with different bacteria. The T cells proliferation was detected by MTT, and cytokine production by ELISA kits. RESULTS: The human bacterial pathogen Staphylococcus aureus and Pseudomonas aeruginosa stimulation for 48 h resulted in the maturation of pDC with production of high quantity of IFN-α at (15.34 ± 2.91) ng/ml and (10.38 ± 1.41) ng/ml, respectively, comparing with that of negative group at (1.36 ± 0.13) ng/ml (P<0.01). Activated pDC could promote the differentiation of naive CD4⁺ T cells to Th1 cells with secretion of IFN-γ at (2.16 ± 0.37) ng/ml and (2.73 ± 1.11) ng/ml, respectively, comparing with that of positive control at (2.55 ± 0.23) ng/ml (P > 0.05). Activated pDC showed higher T cell stimulatory capacities [proliferation index (PI) was 4.36 and 4.05, respectively] than that of non-activated pDC (PI was 1.23 and 0.13, respectively) (P < 0.01). CONCLUSION: Staphylococcus aureus and Pseudomonas aeruginosa activated pDC may play a key role in SR of leukemia following severe infections.

[Effect of plasmacytoid dendritic cells activited by bacteria on spontaneous remission of leukemia].

Spontaneous remission (SR) of leukemia is a rare event in clinic, which possibly correlated with severe infection and sepsis, but its exact mechanism has not been confirmed. Plasmacytoid dendritic cells (pDC) and myeloid dendritic cells (mDC) play a key role in innate and adaptive immunity respectively. A patient with severe infection of staphylococcus aureus acquired completely spontaneous remission (SR), moreover a increased number of pDC were observed, suggesting that bacteria-activated pDC may play an important role in SR. This study was purposed to explore if the bacteria can stimulate pDC successfully and get a functional pDC. Both pDC and mDC were isolated from freshly collected, leukocyte-rich buffy coats from healthy blood donor and leukemic patient with SR by using MACS and FACS. The pDC were cultured in RPMI 1640 medium and were stimulated with different kinds of bacteria and the expression of CD40, CD86 and HLA-DR on the cell surface was analyzed by flow cytometry. The cytokine (IFN-α, IL-12, IFN-γ, IL-2, IL-4, IL-10) production was measured by using ELISA kits. The results showed that the stimulation with staphylococcus aureus and pseudomonas aeruginosa resulted in the maturation of pDC, which secrete a large number of IFN-α and promote the differentiation of naive CD4⁺ T cells to Th1 cells. The activated pDC expressed high level of CD40 and CD86 and showed higher T cell stimulatory capacities. It is concluded that staphylococcus aureus and pseudomonas aeruginosa can activate pDC, the activated pDC secrete high quantity of IFN-α. This result suggests that bacteria stimulated pDC may play a key role in SR of leukemia following severe infections.