[Adsorptive Remediation of Cr(â ¥) Contaminated Groundwater with Chemically Synthesized Schwertmannite].

Schwertmannite is usually naturally found in acidic mining wastewater and frequently used in the adsorption of heavy metal anions from water and wastewater. Schwertmannite was synthesized through a facile chemical method and utilized to remove Cr(Ⅵ) from contaminated groundwater. The kinetics, thermodynamics and isotherms, as well as the effects of environmental factors on the Schwertmannite adsorption processes were investigated. The experimental results showed that the synthesized Schwertmannite had a strong adsorption capability of Cr(Ⅵ) from aqueous solution. At the pre-set initial concentrations of Cr(Ⅵ), the Schwertmannite adsorption of Cr(Ⅵ) achieved equilibrium within 24 h, and the Lagergren's second-order model fitted the adsorption process better compared to Lagergren's first-order model and intraparticle diffusion model. Langmiur equation fitted the adsorption isotherms better than Freundlich equation. The Cr(Ⅵ) adsorption on Schwertmannite mainly involved ion exchange reaction between Cr(Ⅵ) and anions such as OH- and SO42- and surface complexation reactions. The ΔHθ and ΔGθ were 6.368 kJ·mol-1 and -1.215 kJ·mol-1, respectively, therefore the adsorption of Cr(Ⅵ) was a spontaneous and endothermic process. The removal of Cr(Ⅵ) from aqueous solution increased with increasing Schwertmannite dosage at pH=4.5. Acidic pH in the range of 4.5-6 favored Cr(Ⅵ) removal with Schwertmannite compared to that under basic conditions. Under the conditions of 5 mg·L-1of initial Cr(Ⅵ) concentration, 0.5 g·L-1 of Schwertmannite dosage, pH=6, maximum Cr(Ⅵ) removal of 93.1% was achieved and the adsorption capacity of Cr(Ⅵ) with Schwertmannite reached up to 40.4 mg·g-1. Batch tests showed that the presence of HCO3- and SO42- inhibited the adsorption of Cr(Ⅵ) while Cl- had no significant impact. Cations and natural organic matter had a pH-dependent impact on Cr(Ⅵ) removal:at pH=8 natural organic matter and cations would significantly inhibit the Cr(Ⅵ) sorption, while the impact could be neglected at weak acidic conditions (pH=6).

[An investigation on correlation of severity of brain injury with the expression of activin A and C-reactive protein].

OBJECTIVE: To determine the dynamic change in serum levels of activin A (ACTA) and C-reaction protein (CRP) in patients with brain injury, and to investigate its significance. METHODS: A prospective study was conducted. A total of 57 adult patients with brain injury occurring within 24 hours admitted to intensive care unit (ICU) of the First Affiliated Hospital of Zhengzhou University from August 2012 to June 2013 were enrolled. The patients were allocated into three groups according to their Glasgow coma scale (GCS) as follows: minor brain injury (GCS 13-15, n=17), moderate brain injury (GCS 9-12, n=18), heavy brain injury (GCS 3-8, n=22). The clinical and related laboratory data (reflecting the function of liver, kidney, lung, blood coagulability etc.) were recorded after ICU admission. At the same time, venous samples were collected on the day 1, 2, 3, 5, 7 after ICU admission for determination of ACTA with enzyme linked immunosorbent assay (ELISA) and CRP with fluorescence immunoassay technology. The correlation between ACTA and CRP was analyzed by linear correlation. The receiver operating characteristic (ROC) curve was plotted to analyze the accuracy of ACTA and CRP as a prognostic indicator in brain injury. Fifteen healthy persons were enrolled as the control group. RESULTS: The serum levels of ACTA and CRP in patients with minor, moderate and heavy brain injury were significantly higher than those in healthy control group [ACTA (µg/L): 23.96±3.55, 42.06±5.67, 52.32±4.46 vs. 13.66±2.45, all P<0.01; CRP (mg/L): 14.12±2.45, 23.05±2.85, 30.93±2.35 vs. 3.42±2.25, all P<0.01]. As the patients' condition worsening, levels of ACTA and CRP tended to elevate (all P<0.01). Levels of ACTA and CRP in minor, moderate and heavy brain injury groups were increased after ICU admission. On day 3, levels of serum ACTA and CRP reached the peak values [ACTA (µg/L):30.62±2.54, 51.35±2.55, 60.52±2.55; CRP (mg/L): 18.62±2.64, 30.35±2.25, 37.52±2.55], and then they lowered gradually. In minor and moderate brain injury groups, the levels of ACTA and CRP were slowly descending, and on day 7, they maintained at a lower level [ACTA (µg/L): 13.68±2.54, 37.74±2.55; CRP (mg/L): 6.68±2.44, 19.74±2.55]. On the contrary, the levels of ACTA and CRP in heavy brain injury group persistently maintained at a high level on day 7 [ACTA: (42.32±2.54) µg/L, CRP: (33.32±2.56) mg/L]. There were significant differences in ACTA and CRP among different degrees of brain injury groups (all P<0.01). There was a positive correlation between ACTA and CRP (r=0.958, P=0.007). ROC curve analysis showed that the sensitivity for brain injury prediction was 93.3% for ACTA with specificity 95.0%, area under ROC curve(AUC) 0.843, and the sensitivity for CRP was 89.1% with specificity 68.2%, AUC 0.723. CONCLUSIONS: Serum levels of ACTA and CRP in patients with brain injury are strongly correlated with the severity of the injury. Furthermore, ACTA is more sensitive than CRP in detecting early brain injury. Therefore, ACTA is a specific factor for detecting brain injury.