The role of sulfur cycling in arsenic behavior under reducing conditions is not well-understood in previous investigations. This study provides observations of sulfur and oxygen isotope fractionation in sulfate and evaluation of sulfur cycling-related biogeochemical processes controlling dissolved arsenic groundwater concentrations using multiple isotope approaches. As a typical basin hosting high arsenic groundwater, the western Hetao basin was selected as the study area. Results showed that, along the groundwater flow paths, groundwater δS, δO, and δC increased with increases in arsenic, dissolved iron, hydrogen sulfide and ammonium concentrations, while δC decreased with decreasing Eh and sulfate/chloride. Bacterial sulfate reduction (BSR) was responsible for many of these observed changes. The δS indicated that dissolved sulfate was mainly sourced from oxidative weathering of sulfides in upgradient alluvial fans. The high oxygen-sulfur isotope fractionation ratio (0.60) may result from both slow sulfate reduction rates and bacterial disproportionation of sulfur intermediates (BDSI). Data indicate that both the sulfide produced by BSR and the overall BDSI reduce arsenic-bearing iron(III) oxyhydroxides, leading to the release of arsenic into groundwater. These results suggest that sulfur-related biogeochemical processes are important in mobilizing arsenic in aquifer systems.

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Lycium barbarum, a famous Chinese medicinal herb, has a long history of use in traditional medicine as an antioxidant and to promote sexual fertility. Polysaccharides are the most important functional constituents in L. barbarum fruits. In this study, male rats were exposed to subchronic (60)Co-γ irradiation to investigate the effects of LBP on sperm quantity and motility, sexual ability, serum hormone levels, oxidative status and testicular tissue DNA damage on days 1, 7 and 14 of treatment. It was found that LBP significantly increased the sperm quantity and motility, shortened the erection, capture and ejaculation latencies, increased the number of captures and ejaculations, and improved the sexual ability of male rats. LBP also played a significant role in the recovery of serum testosterone levels, increased superoxide dismutase activity, decreased malondialdehyde levels, promoted oxidative balance and rescued testicular DNA damage. In conclusion, LBP has significant protective effects against damage induced by local subchronic exposure to (60)Co-γ irradiation, allowing rats to achieve near-complete recovery with LBP treatment.

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This paper presents a 50 Gb/s per lane hybrid BiC-MOS and silicon photonic integrated circuit for use in fiber optic communications. Fine pitch copper pillars are used to integrate electronics and silicon photonics. The resulting device demonstrates the generation and detection of up to 56 Gb/s NRZ optical signals over 2-km standard single-mode fiber at 1310-nm wavelength. At 40 Gb/s, the link operates error free, and at 56 Gb/s well below KR4 RS-FEC operating BER. The power dissipation of TX including CW laser is 600 mW (450-mW driver, 150-mW CW laser), RX is 150 mW, resulting in total per channel of less than 750 mW.

With the optimized methods, the analytical precision of the δ(13)C(DIC) and δ(13)C(DOC) values of the reference samples was 0.02‰. The precision of δ(13)C(DIC) and δ(13)C(DOC) values in groundwater samples was 0.03‰ and 0.17‰, respectively. For the sequential determination of the DIC and DOC carbon isotope ratios, the precision of the δ(13)C(DIC) and δ(13)C(DOC) values in reference samples was better than 0.2‰.