To our knowledge, this is the first report to identify the involvement of sulfite reductase in selenite reduction under physiological conditions. P. rettgeri HF16 could be a suitable and robust biocatalyst for the bioremediation of selenite, and would accelerate the efficient and economical synthesis of selenium nanoparticles.Dissolved organic matter (DOM) is a crucial controlling factor in mobilizing arsenic. However, direct delineations of DOM regarding both optical properties and molecular signatures were rarely conducted in high-arsenic groundwater. Here, both groundwater and surface water were taken from the Hetao Basin, China, to decipher DOM properties with both optical spectrophotometer and Fourier transform ion cyclotron resonance mass spectrometry. The tryptophan-like component (C4) was averagely less than 30% in groundwater DOM, being positively associated with high H/C-ratio molecules (H/C > 1.2) and mainly grouped as highly unsaturated and phenolic compounds and aliphatic compounds. Other three humic-like components (C1, C2, C3) had positive associations with low H/C-ratio molecules (H/C less then 1.2), which mainly consisted of highly unsaturated and phenolic compounds, polyphenols, and polycyclic aromatics. Groundwater arsenic concentrations were positively correlated with humic-like, low H/C-ratio, and recalcitrant organic compounds, which may be the consequence of labile organic matter degradation. The degradation caused Fe(III) oxide reduction and mobilized the solid arsenic. In addition, high abundances of these recalcitrant organic compounds in high-arsenic groundwater may contribute to arsenic enrichment via electron shuttling, competition for surface sites, and complexation process. It suggested that groundwater proxies would be either the result or the cause of biogeochemical processes in aquifers.Internal nitrogen (N) loading of lakes is commonly controlled by sediment dredging, although its comprehensive effect on internal N loading remains unclear. Herein, we examined the long-term effects of sediment dredging on internal N loading from a new perspective on the N budget at the sediment-water interface (SWI) through a simulation of field dredging performed by incubating intact sediment cores from a shallow eutrophic lake (Lake Taihu). We further evaluated the role of settling particles (SP) in the recovery of N cycle processes after dredging and its potential impact on the N budget. Our results demonstrated that dredging could help reduce organic matter and total N in sediments; improve the redox environment of the SWI; slow down N mineralization, N fixation, denitrification, and anaerobic ammonia oxidation (anammox); and alter the N budget at the SWI and the contribution of various N cycle processes. However, the input of SP enriched in fresh organic matter and N could accelerate the recovery of N cycle processes at the SWI, reducing the variation in the N budget and the contribution of each N cycle process caused by dredging. Dredging significantly reduced the N flux at the SWI, which was evident from the reduction of inorganic N release flux and N removal through denitrification and anammox. Therefore, sediment dredging has its advantages and disadvantages in managing internal N loading in lakes. To maintain a long-term control on the release of internal N through sediment dredging, measures should be taken based on the in-lake and watershed to inhibit the inflow and settlement of particulate matter.To overcome the complexity associated with the development of detailed kinetic models for real transportation fuels, surrogate fuel models offer an excellent alternative. The present study reports laminar burning velocity (LBV) measurements of methylcyclohexane (MCH) + air mixtures for mixture temperatures up to 610 K using externally heated diverging channel method (EHDC) method at 1 atm pressure. https://www.selleckchem.com/products/marimastat.html MCH is a commonly used surrogate blend for aviation fuels, gasoline, and diesel, whose kinetic model is simpler to develop. The measurement of laminar burning velocity forms the basis of kinetic model development for such surrogate fuels. The present work reports the measured LBV values for an equivalence ratio range, φ = 0.7-1.4, and their comparison with available experimental data and detailed kinetic model predictions for a mixture temperature range, 353-610 K. Temperature exponent, α is derived using the power-law correlation and good consistency with kinetic model predictions is observed up to 500 K mixture temperatures. At 610 K mixture temperature, an overprediction of ≈12% at φ = 1.05 is observed with JeTSurF 2.0 (2010) model and 27% overprediction with the kinetic model of PoliMi (2014) φ = 1.1. Overall, the reported LBV measurements show slightly better match with the JeTSurF 2.0 (2010) kinetic model than the Wang (2014) kinetic model. Reaction pathway diagrams are drawn to highlight the importance of C2H4 and C2H3 radicals for an increase in the overall reaction rate at 610 K.Amorphous silica nanoparticle (SiNPs) has tremendous potential for a host of applications, while its mass production, broad application and environmental release inevitably increase the risk of human exposure. SiNPs could enter into the human body through different routes such as inhalation, ingestion, skin contact and even injection for medical applications. The cardiovascular system is gradually recognized as one of the primary sites for engineered NPs exerting adverse effects. Accumulating epidemiological or experimental evidence support the association between SiNPs exposure and adverse cardiovascular effects. However, this topic is still in its infancy, and the literature shows high inter-study variability and even contradictory results. New challenges still present in the safety evaluation of SiNPs, and its toxicological mechanisms are poorly understood. Here, scientific papers related to cardiovascular studies of SiNPs in vivo and in vitro were selected, and the updated particle-caused cardiovascular toxicity and potential mechanisms were summarized. Moreover, the understanding of how factors primarily including exposure dose, route of administration, particle size and surface properties, influence the interaction between SiNPs and cardiovascular system was discussed. In particular, the adverse outcome pathway (AOP) framework by which SiNPs cause deleterious effects in the cardiovascular system was described, aiming to provide useful information necessary for the regulatory decision and to guide a safer application of nanotechnology.