Pharmacokinetic Study of Ultrasmall Superparamagnetic Iron Oxide Nanoparticles HY-088 in Rats.

BACKGROUND AND OBJECTIVE: HY-088 injection is an ultrasmall superparamagnetic iron oxide nanoparticle (USPIOs) composed of iron oxide crystals coated with polyacrylic acid (PAA) on the surface. The purpose of this study was to investigate the pharmacokinetics, tissue distribution, and mass balance of HY-088 injection. METHODS: The pharmacokinetics of [55Fe]-HY-088 and [14C]-HY-088 were investigated in 48 SD rats by intravenous injection of 8.5 (low-dose group), 25.5 (medium-dose group), and 85 (high-dose group) mg/100 µCi/kg. Tissue distribution was studied by intravenous injection of 35 mg/100 µCi/kg in 48 SD rats, and its tissue distribution in vivo was obtained by ex vivo tissue assay. At the same time, [14C]-HY-088 was injected intravenously at a dose of 25.5 mg/100 µCi/kg into 16 SD rats, and its tissue distribution in vivo was studied by quantitative whole-body autoradiography. [14C]-HY-088 and [55Fe]-HY-088 were injected intravenously into 24 SD rats at a dose of 35 mg/100 µCi/kg, and their metabolism was observed. RESULTS: In the pharmacokinetic study, [55Fe]-HY-088 reached the maximum observed concentration (Cmax) at 0.08 h in the low- and medium-dose groups of SD rats. [14C]-HY-088 reached Cmax at 0.08 h in the three groups of SD rats. The area under the concentration-time curve (AUC) of [55Fe]-HY-088 and [14C]-HY-088 increased with increasing dose. In the tissue distribution study, [55Fe]-HY-088 and [14C]-HY-088 were primarily distributed in the liver, spleen, and lymph nodes of both female and male rats. In the mass balance study conducted over 57 days, the radioactive content of 55Fe from [55Fe]-HY-088 was primarily found in the carcass, accounting for 86.42 ± 4.18% in females and 95.46 ± 6.42% in males. The radioactive recovery rates of [14C]-HY-088 in the urine of female and male rats were 52.99 ± 5.48% and 60.66 ± 2.23%, respectively. CONCLUSIONS: Following single intravenous administration of [55Fe]-HY-088 and [14C]-HY-088 in SD rats, rapid absorption was observed. Both [55Fe]-HY-088 and [14C]-HY-088 were primarily distributed in the liver, spleen, and lymph nodes. During metabolism, the radioactivity of [55Fe]-HY-088 is mainly present in the carcass, whereas the 14C-labeled [14C]-HY-088 shell PAA is eliminated from the body mainly through the urine.

Efficient removal of nitrogen and phosphorus in aqueous solutions using modified water treatment residuals-sodium alginate beads.

A high-performance sorbent, modified water treatment residuals-sodium alginate beads (WTR-SA beads), was prepared through a series of salt and combined thermal roasting composite modification between water treatment residuals and sodium alginate. The properties of modified WTR-SA beads composites were characterized by SEM-EDS, FT-IR, XRD, and BET. The adsorption performance of WTR-SA beads was investigated in removing nitrogen and phosphorus from wastewater. Compared to the unmodified WTR, the removal efficiency of nitrogen and phosphorus onto the modified WTR-SA beads was increased from 22.34 and 77.13% to 95.14 and 98.31%, respectively. The adsorption capacities of nitrogen and phosphorus onto the modified WTR-SA beads were reach a maximum of 2.52 mg/g and 6.45 mg/g, respectively. The adsorption behavior can be well described using a quasi-second-order kinetic model and Langmuir isotherm model. The thermodynamic properties of nitrogen adsorption indicated that the adsorption was spontaneous and exothermic. On the contrary, the adsorption process of phosphorus is an endothermic reaction. The adsorption of nitrogen by modified WTR-SA beads is mainly carried out through ion exchange and hydroxyl complexation, and ion exchange plays a major role in it. While, the adsorption of modified WTR-SA beads on phosphorus is affected by three actions: ligand exchange, chemical precipitation, and ion exchange, which ligand exchange is the main effect. Based on these results, it can be concluded that the modified WTR-SA beads are a high efficiency adsorbent for removing nitrogen and phosphorus from domestic and industrial wastewater.

Denitrifying microbial community with the ability to bromate reduction in a rotating biofilm-electrode reactor.

In this study, the microbial community for bromate reduction in a rotating biofilm-electrode reactor (RBER) was investigated. Continuous experiment demonstrated that the bromate reduction by an auto-hydrogenotrophic microbial community was inhibited by high concentration nitrate (50mg/L). The bacterial diversity of RBER were examined through the analyse of 16S rRNA gene sequences of clone libraries. The results showed that the bromate-reducing bacteria were phylogenetically diverse at the phylum level, representing the Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria. The relative abundances of these microbial community represented 99.1% of all phylum in the biofilms when bromate served as the sole electron acceptor. Meanwhile, the Bacillus strains became the largest phylotype and represented about 37% of the total bacteria in the biofilm, indicating that the genus Bacillus played the key role in the auto-hydrogenotrophic process. Moreover, three new bacterial genera, Exiguobacterium, Arthrobacter and Chlorobium appeared with the respective relative abundance being about 7.37%, 1.81%, and 0.52%, which might be the bromate-specific reducing bacteria.

Occurrence and risk assessment of heavy metals in sediments of the Xiangjiang River, China.

Sediment samples were collected from 22 typical metal-polluted sections along the Xiangjiang River (XJR). Spatial distribution and speciation characteristics of heavy metals in sediments of XJR were determined. Furthermore, ecological risk and enrichment degree of metals were assessed by different indices. The results showed that combined metal pollution occurred in sediments of XJR, with content range of Cd, Pb, Zn, Cu, As, Mn, Cr, and Hg reaching 2.95-29.15, 30.93-235.83, 61.50-3771.11, 9.56-81.81, 3.93-46.28, 774.83-8700.72, 10.64-65.16, and 0.13-5.09 mg kg-1, respectively. Pollution levels increased in period of industrialization but decreased after thousands of pollution enterprises were banned. Sections with serious pollution and higher risk were mainly located at Hengyang and Chang-Zhu-Tan regions (Changsha, Zhuzhou, and Xiangtan) for contaminations of Cd, As, Pb, and Hg. Values of both enrichment factor and geo-accumulation index followed the order Cd > Hg > Zn > Mn > Pb > Cu > As > Cr. Bioavailable fractions followed the order Cd (66.93 %), Zn (33.80 %), Pb (30.81 %), Mn (18.38 %), Hg (17.58 %), Cu (10.20 %), As (9.81 %), and Cr (7.65 %). Considering their bioavailability, biotoxicity, or abundance, contamination of Cd was the most dominant, and pollution of other metals should not be ignored.

Geochemical characteristics of inorganic sulfur in Shijing River, South China.

Different inorganic sulfur species distributed in overlying water, pore water and sediment in a heavily polluted river were determined. The concentrations of S(2-) and SO(4)(2-) in the overlying water were much more than those in the pore water. This result perhaps indicates the S(2-) was mainly from discharged wastewater, not from sediment resuspension. In the sediments, acid-volatile sulfide, chromium(ii)-reducible sulfide, and elemental sulfur were determined by a modified diffusion method. The results indicate that acid-volatile sulfide was the dominant component of the reduced inorganic sulfur, making up about 62% of the total reduced inorganic sulfur.