Effects of physicochemical properties of Au cyanidation tailings on cyanide microbial degradation.

The initial cyanide (CN-) concentration and amount of co-contaminants in GCTs can inhibit bacterial growth and reduce the CN--degrading ability of bacteria. Several microorganisms can biotransform a wide range of organic and inorganic industrial contaminants into nontoxic compounds. However, active enzymatic CN- metabolism processes are mostly constrained by the physical and chemical characteristics of GCTs. High concentrations of toxic metal co-contaminants, such as, Pb, and Cr, and factors, such as pH, temperature, and oxygen concentration create oxidative stress and limit the CN--degrading potential of cyanotrophic strains. The effects of such external and internal factors on the CN--degrading ability of bacteria hinder the selection of suitable microorganisms for CN- biodegradation. Therefore, understanding the effects of the physicochemical properties of GCTs on cyanobacteria strains can help identify suitable microbes and favorable environmental conditions to promote microbial growth and can also help design efficient CN- biodegradation processes. In this review, we present a detailed analysis of the physicochemical properties of GCTs and their effects on microbial CN- degradation.

Combined lumbar pelvic fixator for treatment of unstable vertical fracture and dislocation of old posterior pelvic ring / 中华骨科杂志

Objective:To investigate the clinical effect of using combined lumbar pelvis fixation device in the treatment of old vertical unstable fracture dislocation of posterior pelvic ring.Methods:Data of 7 patients with old vertical unstable fracture dislocation of posterior pelvic ring admitted and followed up from January 2017 to April 2020 were retrospectively analyzed, including 4 males and 3 females with an average age of 42.4 years old (range, 22-73 years old). There were 3 cases of traffic injury, 3 cases of falling injury and 1 case of tumble injury. According to Tile classification for pelvic fractures, there were 5 cases of type C1, 1 case of type C2 and 1 case of type C3. The average time from fracture to surgery was 5.4 weeks (range, 3-10 weeks). Among the 7 patients, 4 patients' posterior ring fractures were fixed by combined lumbar pelvic triangle fixation, and 3 patients' posterior ring fracture were fixed by combined lumbar pelvic fixation. 4 patients' anterior ring injury were not treated, 2 patients' anterior ring injury were treated by closed cannulated screw and internal fixation, and 1 patient's anterior ring injury was fixed by INFIX and cannulated screw. Every patient's operating time, intraoperative blood loss, length of incision and times of X-ray fluoroscopy were recorded. Pelvic X-ray and CT scan were taken postoperatively to observe the condition of reduction and screw position. Postoperative fracture reduction quality was assessed by Matta radiological criteria and Majeed criteria was used at the final follow-ups to evaluate the degree of functional recovery after pelvic fracture.Results:The average operating time of 7 patients was 143 min (range, 96-205 min); the intraoperative average blood loss was 579 ml (range, 300-1 650 ml); the average length of incisions was 12.9 cm (range, 9-15 cm) and the average time of X-ray fluoroscopy was 27 times (range, 15-52 times). Postoperative X-ray and CT scan showed that the displacements of the posterior rings were reset well and all the hollow screws were located accurately and firmly. Postoperative radiation quality was evaluated according to Matta radiological criteria, and there were 4 cases of excellent, 2 cases of good and 1 case of fair, with an excellent and good rate of 85.7% (6/7). Seven patients had good fracture union. The average followed up time for all 7 patients was 12 months (range, 6-16 months). At the last follow-up, imaging examination showed good reduction of the sacroiliac joint, and the reduction of anterior and posterior rings were not lost. The healing time was 14.2 weeks (range, 12-20 weeks). Majeed score: postoperative 4.90±6.64 points (range, 48-58 points), postoperative 3 months 71.40±7.32 points (range, 67-75 points), postoperative 6 months 84.90±8.14 points (range, 68-96 points), the difference was statistically significant ( F=0.614, P=0.004). Majeed score 6 months after operation showed that 5 cases were excellent, 1 case was good and 1 case was fair, and the excellent and good rate was 85.7% (6/7). Conclusion:Using combined lumbar pelvis fixation device in the treatment of old vertical unstable fracture dislocation of posterior pelvic ring has good reduction quality, high fixed strength and good postoperative effect.