Although the Ca2+-F− association is of great importance for aqueous environments and industrial systems containing F−, as well as for defluorination processes, many details of the association solvation structures and...

The solubility of MgF 2 , CaF 2 , and ZnF 2 in aqueous solution is seldom studied. Their solubility data available in the literature conflict with each other, and their change tendency with temperature is hard to draw. In this work, we elaborately measured their solubility over the temperature range from 298.15 to 353.15 K. To guarantee the data reliability, various methods including ethylenediamine tetraacetic acid disodium salt dihydrate (EDTA) titration and fluoride ion selective electrode (FISE) have been used for ion content analysis in the saturated solutions and X-ray diffraction (XRD) for equilibrium solid phase identification. Besides, sufficient solid−liquid contact time has been taken to guarantee the equilibrium. The determined results were compared with those reported in the literature, and their differences have been discussed. It was found that the MgF 2 solubility decreases; however, the CaF 2 solubility increases with increasing temperature. In the ZnF 2 + H 2 O system, the equilibrium solid phase is ZnF 2 •4H 2 O (s) at temperatures below 333 K and ZnOHF (s) above 333 K. While the ZnF 2 •4H 2 O (s) solubility is sensitive to temperature, the ZnOHF (s) solubility is insensitive.

Background: Incision-site infiltration with local anesthetics prevents pain on incision site, but pain relief is limited to the first few postoperative hours. Dexamethasone as an adjuvant to local infiltration successfully achieves better postoperative pain relief; however, this has not been studied in craniotomy patients yet. Study Design and Methods: This is a prospective, single-center, blinded, randomized, controlled trial included patients aged between 18 and 64 years, ASA physical status of I-II, scheduled for elective supratentorial tumor craniotomy under general anesthesia. We screened patients for enrollment from April 4, 2019 through August 15, 2019. The final study visit of the last patient was conducted on February 13, 2020. We randomly assigned eligible participants (1:1) to either the dexamethasone group who received incision-site infiltration of 0.5% ropivacaine plus 0.033% dexamethasone (N=70) or the control group who received 0.5% ropivacaine alone (N=70). Primary outcome was the cumulative sufentanil consumption (μg) within 48 hours postoperatively. Primary analysis was performed based on the modified intention-to-treat (MITT) principle. Results: Baseline characteristics were similar between the groups (p>0.05). Sufentanil consumption during the first 48 hours postoperatively was 29.0 (10.7) μg in the dexamethasone group and 38.3 (13.7) μg in the control group (mean difference −9.3, 95% CI −13.4 to −5.1; p<0.001). There was no serious adverse effect directly associated with incision-site infiltration or local dexamethasone use. Conclusion:The addition of dexamethasone to pre-emptive incision-site infiltration with the local anesthetic can reduce about 27% of opioids consumption and the postoperative pain scores within 72 hours after craniotomy. Trial Registration: ClinicalTrials.Gov (NCT03618264).

No abstract

Solubility data for the reciprocal system Ca2+, Mn2+//F–, SO4 2– + H2O is very important for the removal of fluoride or calcium ions from the MnSO4 aqueous solution by CaF2(s) precipitation; however, these data have not been reported in literature to date. In this work, the solubility data for the ternary systems CaF2 + MnSO4 + H2O, CaF2 + MnF2 + H2O, and MnF2 + MnSO4 + H2O and the quaternary systems CaF2 + CaSO4 + MnSO4 + H2O and CaF2 + MnF2 + MnSO4 + H2O were measured in detail at 298.15 K. The results showed that CaF2(s) solubility increases monotonically with increasing MnSO4 concentration in the CaF2 + MnSO4 + H2O system, and MnSO4 produces a stronger salting-in effect on CaF2(s) than ZnSO4. CaF2(s) solubility decreases with the increase in the MnF2 concentration and increases again after reaching the minimum value. In the MnF2 + MnSO4 + H2O system, the addition of MnSO4 results first in a decrease and then in an increase of the MnF2(s) solubility, similar to the MgF2(s) solubility behavior in the MgF2 + MgSO4 + H2O system. In the CaSO4·2H2O(s)-saturated solution, CaF2(s) solubility increases with increasing MnSO4 concentration but is generally lower than that in the pure MnSO4 aqueous solution. In the MnF2(s)-saturated solution, CaF2(s) solubility increases with increasing MnSO4 concentration but is remarkably lower than that in the pure MnSO4 aqueous solution. The reciprocal system Ca2+, Mn2+//F–, SO4 2– + H2O exhibits cosaturated phase fields of CaSO4·2H2O(s)-CaF2(s)-MnSO4·H2O(s), CaF2(s)-MnSO4·H2O(s), and CaF2(s)-MnSO4·H2O(s)-MnF2(s).