Oxalic acid activated bone meal for immobilization of Pb and Cd contaminated soils.

Bone meal (BM) is a cost-effective and low-carbon material to remediate heavy metal contaminated soils. Moreover, its immobilization efficiency for heavy metals still requires improvement. This study aimed to assess the activation effect of oxalic acid on the BM to develop an oxalic acid-activated bone meal (ABM) for improving immobilization efficiency. Several series of tests, including the available phosphorus content test, toxicity characteristic leaching procedure (TCLP), modified European Community Bureau of Reference (BCR) sequential extraction procedure, and X-ray diffraction (XRD) analysis, are used to investigate the effect of activation on the immobilization ability and chemical speciation of lead (Pb) and cadmium (Cd) in soils and the different mechanisms of Pb/Cd immobilization using the ABM and BM. The results indicate that the ABM possesses a higher solubility than the BM. The activation of BM achieves optimal effect when using 1 mol/L oxalic acid solution with a liquid-solid ratio of 2:1. The TCLP and BCR test results show that the ABM significantly outperforms the BM in terms of Pb immobilization. The leaching concentration of Pb from ABM immobilized soils can meet regulatory limits in China and the USA, and it is also 30 to 75% lower than that from BM immobilized soils. Regarding Cd immobilization, ABM outperforms BM after 90 days of curing. The XRD analysis shows that heavy metal phosphates are the primary products of Pb and Cd immobilized by ABM, whereas heavy metal carbonates are the main products after the immobilization by BM.

[Effect of flurbiprofen combined different concentrations of ropivacaine local infiltration on postoperative analgesia after laparoscopic cholecystectomy].

OBJECTIVE: To investigate the effects of postoperative analgesia after laparoscopic cholecystectomy using intravenous flurbiprofen combined with different concentrations of ropivacaine incision infiltration. METHODS: Eighty patients who underwent traditional laparoscopic cholecystectomy received standard general anesthesia. At the end of surgery, patients were randomly divided into four groups: group Con (control group: no analgesics was administered, n=20); group F (flurbiprofen group: 100 mg of flurbiprofen was given intravenously with no incision infiltration, n=20); group FR(0.25) (100 mg of flurbiprofen was given intravenously, combined with 0.25% ropivacaine incision infiltration, 2 mL per incision, 6 mL in total, n=20) and group FR(0.5) (100 mg of flurbiprofen was given intravenously, combined with 0.5% ropivacaine incision infiltration, 2 mL per incision, 6 mL in total, n=20). The intensity of postoperative pain was evaluated using numeric rating scale (NRS) in a double-blinded manner. Intramuscularly 50 mg of meperidin was administered as rescue medication when NRS was above 4. The NRS and the associated side effects were observed and recorded at the end of 0, 2, 6, 12, 24, and 48 hours postoperatively (T(0 h)h,T(2 h),T(6 h),T(12 h),T(24 h),and T(48 h)). RESULTS: There was no obvious difference among the four groups in respect of gender, age, body weight, baseline blood pressure, heart rate(HR), and total doses of sufentanil and remifentanil during operation and surgical time(P>0.05).There were significant differences among group FR(0.25)(2.34 ± 0.89,3.01 ± 1.27,2.79 ± 0.94), group FR(0.5)(2.42 ± 0.79, 2.69 ± 0.96, 2.03 ± 0.87)and group Con(3.42 ± 1.23, 5.98 ± 1.46, 4.53 ± 0.92)in NRS at T(2 h), T(6 h), and T(12 h)(P<0.05).Systolic blood pressures (SBP) of patients in group FR(0.25) [(114.19 ± .74) mmHg,(108.31 ± 7.62) mmHg) and group FR(0.5) [(115.26 ± 8.95) mmHg,(111.25 ± 9.12) mmHg] were significantly lower than those of patients in group Con [(137.11 ± 8.71) mmHg,(125.16 ± 8.92) mmHg] at T(2 h) and T(6 h)(P<0.05). Compared with group Con [(81.24 ± 6.64) beats/min], heart rate(HR) was also lower in patients of group FR(0.25) [(69.14 ± 5.92) beats/min] and group FR(0.5) [(70.16 ± 5.25) beats/min] at T(6 h)(P<0.05). There was no obvious adverse effect in all the four groups. CONCLUSION: Intravenous flurbiprofen combined with ropivacaine infiltration could significantly reduce postoperative pain after laparoscopic cholecystectomy, providing more stable hemodynamics. Compared with 0.25% ropivacaine, 0.5% ropivacaine infiltration combined with intravenous flurbiprofen has better and longer analgesic effects.