Study on synergistic inhibition and mechanism of flotation separation of fluorite and calcite by tannin and sodium humate.

At present, the separation technology of fluorite and calcite is still immature, and the research in this paper can promote the improvement of the separation technology of fluorite and calcite. The selective inhibition mechanism of tannin and humate sodium on calcite was studied by means of actual ore flotation test, single mineral flotation test, Zeta potential measurement and FT-IR spectroscopy. The results show that the mixture of tannin and sodium humate inhibitor has a good inhibitory effect on carbonate under weak alkaline condition. The reaction products of sodium humate, tannin and calcium ions in solution interact with organic compounds adsorbed on the surface of calcite, forming multilayer adsorption on the surface of calcite, making calcite more hydrophilic. Based on density functional theory, Materials Studio (MS) was used to calculate the relevant adsorption energy, and the result was as follows: (a) compared with fluorite, tannin and humate sodium molecules are more easily adsorbed on the surface of calcite. (b) Compared with calcite alone adsorption of tannin molecules or sodium humate molecules, the adsorption state will be more stable, and the effect of tannin and sodium humate synergistic inhibition of calcite is better than the effect of inhibition alone. Therefore, using tannin and sodium humate as a combination inhibitor can effectively separate fluorite and calcite, which will promote the development and utilization of fluorite ore in industry.

[Effectiveness analysis of percutaneous parallel screw fixation via posterolateral "safe zone" for Hawkins type â - â ¢ talar neck fractures].

Objective: To explore the effectiveness of the percutaneous parallel screw fixation via the posterolateral "safe zone" for Hawkins type Ⅰ-Ⅲ talar neck fractures. Methods: A retrospective analysis was conducted on the clinical data from 35 patients who met the selection criteria of talar neck fractures between January 2019 and June 2021. According to the surgical method, they were divided into a study group (14 cases, using percutaneous posterolateral "safe zone" parallel screw fixation) and a control group (21 cases, using traditional open reduction and anterior cross screw internal fixation). There was no significant difference in gender, age, affected side, Hawkins classification, and time from injury to operation between the two groups ( P>0.05). The operation time, bone healing time, complications, and Hawkins sign were recorded, and the improvement of pain and ankle-foot function were evaluated by visual analogue scale (VAS) score and American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score at last follow-up. The overall quality of life was assessed by the short form of 12-item health survey (SF-12), which was divided into physical and psychological scores; and the satisfaction of patients was evaluated by the 5-point Likert scale. Results: The operation time in the study group was significantly shorter than that in the control group ( P<0.05). All patients werefollowed up 13-35 months, with an average of 20.6 months; there was no significant difference in the follow-up time between the two groups ( P>0.05). The time of bone healing in the study group was shorter than that in the control group, and the positive rate of Hawkins sign (83.33%) was higher than that in the control group (33.33%), and the differences were significant ( P<0.05). In the control group, there were 2 cases of incision delayed healing, 7 cases of avascular necrosis of bone, 3 cases of joint degeneration, 1 case of bone nonunion, and 3 cases of internal fixation irritation; while in the study group, there were only 2 cases of joint degeneration, and there was a significant difference in the incidence of complications between the two groups ( P<0.05). At last follow-up, there was no significant difference in VAS score between the two groups ( P>0.05), but the SF-12 physical and psychological scores, AOFAS ankle and hindfoot scores, and patients' satisfaction in the study group were significantly better than those in the control group ( P<0.05). Conclusion: The treatment of Hawkins type Ⅰ-Ⅲ talar neck fractures with percutaneous parallel screw fixation via the posterolateral "safe zone" can achieve better effectiveness than traditional open surgery, with the advantages of less trauma, fewer complications, faster recovery, and higher patient satisfaction.

Photocatalytic degradation of reactive brilliant blue KN-R by Ti-doped Bi2O3.

In this study, different compositions of Ti-doped Bi2O3 photocatalytic materials were prepared by chemical solution decomposition method. It was used to degrade reactive brilliant blue KN-R, and then characterized by XRD, SEM, UV-vis DRS, XPS, photocurrent, and other detection methods. The results show that when the catalyst dosage is 1.0 g/L and the initial concentration of reactive brilliant blue KN-R is 20 mg/L, the degradation rate of pure Bi2O3 to reactive brilliant blue KN-R is 75.30%; the Ti doping amount is 4% (4Ti/Bi2O3), 4Ti/Bi2O3 had the best degradation effect on reactive brilliant blue KN-R, and the degradation rate could reach 93.27%. When 4Ti/Bi2O3 was reused for 4 times, the degradation rate of reactive brilliant blue KN-R only decreased by 6.91%. Doping Ti can inhibit the growth of Bi2O3 grains, making the XRD peak of Ti/Bi2O3 material wider. The pure Bi2O3 particles are larger and the surface is smooth. With the increase of Ti doping content, the surface of Ti/Bi2O3 material grows from roughness to nanofibrous Bi4Ti3O12. The visible light absorption performance and electron separation and transfer ability of Bi2O3 are significantly improved by doping Ti ions. The band gap is reduced from 2.81 to 2.75 eV. In conclusion, doping Ti enhances the visible light absorption and electron separation and transfer capabilities of Bi2O3, reduces the band gap, and improves the surface morphology, which makes Bi2O3 have higher photocatalytic performance.

Osteotomies combined with soft tissue procedures for symptomatic flexible flatfoot deformity in children.

BACKGROUND: The indications for surgery, timing, and procedure in children with flexible flatfoot deformity remain controversial. This study aims to evaluate the efficacy of osteotomies combined with soft tissue procedures in children with flexible flatfoot aged 9-14 years. METHODS: Twenty-eight children (47 feet) with flexible flatfoot who underwent osteotomy combined with soft tissue surgery between July 2014 and October 2017 were included in this study. The main observational indexes included the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Foot and Ankle Outcome Score (FAOS), talo-navicular coverage angle (TNCA), talar-first metatarsal angle (T1MA) on the foot anteroposterior (AP) view, calcaneal pitch angle and Meary's angle on the foot lateral view, and calcaneus valgus angle (CVA) on the Saltzman view. Intra- and interobserver reliabilities were assessed using intra-class correlation coefficient (ICC). Patient's satisfaction was assessed. RESULTS: All patients were followed up for an average duration of 29.7±8.6 months. The results showed that the mean AOFAS and FAOS had improved significantly from 56.6±8.0 and 47.4±9.5 preoperatively to 88.4±3.9 and 83.2±6.8 at final follow-up (P<0.001), respectively. There were statistically significant differences between preoperative and postoperative scores in all FAOS subscales (P<0.001). Radiographic parameters, such as TNCA (P<0.001) and T1MT (P<0.001) on foot AP views, calcaneal pitch angle (P=0.014) and Meary's angle (P<0.001) on foot lateral views, and CVA (P<0.001) on Saltzman views, had improved significantly. We observed overall substantial to perfect intra- and inter-observer agreements for all radiographic measurements preoperatively and final follow-up. All patients and their parents were satisfied with the functional outcomes. CONCLUSION: Osteotomies combined with soft tissue procedures is an effective strategy for flexible flatfoot deformity in children, as it results in favorable radiographic and functional outcomes.

Additional evidence supports association of common genetic variants in MMP3 and TIMP2 with increased risk of chronic Achilles tendinopathy susceptibility.

OBJECTIVES: To systematically evaluate the effects of matrix metalloproteinase-3 (MMP3) and tissue inhibitor of metalloproteinase-2 (TIMP2) on chronic Achilles tendinopathy (AT) susceptibility. Chronic AT is one of the most prevalent and severe injuries in athletes. Early studies suggested that tendon extracellular matrix (ECM) may be involved in the pathogenesis of chronic AT. MMP3 is an important member of the MMP family and is important to ECM integrity. In addition, tissue inhibitor of metalloproteinase-2 (TIMP2) can indirectly limit the activity of MMP3 activity. DESIGN: Case-control genetic association study. METHODS: A total of 1084 chronic AT patients and 2188 controls with Chinese Han ancestry were recruited. Twenty-one SNPs, 4 mapped to MMP3 and 17 mapped to TIMP2, were selected and genotyped. Genetic association analyses and eQTL analyses were performed. In addition, we also examined the potential effects of epistasis using a case-only study design. RESULTS: Two SNPs, rs679620 (OR=0.82, P=0.0006, MMP3) and rs4789932 (OR=1.2, P=0.0002, TIMP2) were identified to be significantly associated with chronic AT risk. No significant results were obtained from epistasis analyses. SNP rs4789932 was identified to be strongly associated with the gene expression level of TIMP2 in two types of human tissues: atrial appendage (P=0.0003) and tibial artery (P=0.0009). CONCLUSIONS: We have identified genetic polymorphisms in MMP3 and TIMP2 to be significantly associated with chronic AT risk. Further eQTL analyses indicated that SNP rs4789932 of TIMP2 was related to the gene expression levels of TIMP2. These results suggest important roles for MMP3 and TIMP2 in the pathophysiology of chronic AT.