Efficient dewatering of unclassified tailings with flocculant: role of ultrasound.

Flocculants play an important role in the solid-liquid separation of tailings slurry, and its dosage directly impacts on the dewatering efficiency of tailings. Herein, the influence of ultrasonication on flocculant dosage in dehydration process of unclassified tailings was studied. The effects of flocculant dosage on initial settling rate (ISR), underflow concentration, and effective settling time in the process were investigated in detail. The directivity characteristics of ultrasound transducers with different frequencies in unclassified tailings slurry was simulated by MATLAB. The morphologies of underflow tailings at different flocculant dosages were detected by environmental scanning electron microscope (E-SEM). The relationship between flocculant dosage and fractal dimension (DF) was quantitatively analyzed based on fractal theory. The influence mechanism of flocculant on the settling and thickening of unclassified tailings was revealed. The results show that the optimum flocculant dosage for the ultrasonically treated tailings slurry is 40 g/t, at which the ISR reach a maximum value of 0.262 cm/min and the final underflow concentration (FUC) reach a maximum value in 60 min. Compared with settling without ultrasonication, the optimum flocculant dosage is reduced by 10 g/t, the ISR increases by 10.45%, the effective settling time is reduced by 50 min, and the FUC increases by 1.65%. The fractal dimension of underflow tailings first increases and then decreases with the increase in flocculant dosage, the relationship of which is in accordance with Lorentz model.

Inhibition of vitamin D analog eldecalcitol on hepatoma in vitro and in vivo.

Hepatoma is a serious liver cancer with high morbidity and mortality. Eldecalcitol (ED-71), a vitamin D analog, is extensively used as anti-cancer agent in vitro. Hepatocellular carcinoma cell, SMMC-7721 cell lines were used in this study. Transwell assay, cell apoptosis and cell cycle detection assays were investigated after treatment with ED-71 and phosphate buffered saline (PBS) as control. Sizes of tumors were measured after ED-71 treatment in a mouse model. E-cadherin and Akt gene expressions were detected by real-time PCR (RT-PCR). The results showed that cell invasion and migration were decreased markedly after ED-71 treatment compared to control group. Cell cycle detection showed that the G2 stage was 13.18% and total S-stage was 41.16% in the ED-71 group and G2 stage: 22.88%, total S-stage: 27.34% in the control group. Cell apoptosis rate was promoted in the ED-71 group. Size of the tumors reduced more after the ED-71 treatment than the PBS treatment in mice. ED-71 markedly inhibited the expression of Akt and E-cadherin, either detected by immunohistochemistry or RT-PCR. ED-71 treatment can inhibit the hepatoma agent proliferation by increasing the E-cadherin expression and decreasing Akt expression. Therefore, these findings provide novel evidence that ED-71 can be used as an anti-hepatoma agent.

Effect of ultrasound on the flocculation-sedimentation and thickening of unclassified tailings.

In back-fill mining, how to rapidly increase the concentration of tailings is an important problem facing mining engineers. In this paper, the effects of ultrasound frequency (17-25 kHz), power (50-100 W), duration (5-20 min) and start time (3-12 min) on the final underflow concentration (FUC) of unclassified tailings (UTs) were investigated. The flocculation-sedimentation and thickening of tailings were compared with and without ultrasound application. The response surface method was applied to analyze the primary and secondary relationships and interactive relationships between the various ultrasound operating parameters and the FUC, and the optimal conditions were determined. In addition, Environmental Scanning Electron Microscope (E-SEM) was used to analyze the structural changes of underflow aggregates and clearly demonstrated a denser underflow after ultrasound treatment. The results indicated that ultrasound can significantly improve the underflow concentration of the UTs slurry. The frequency and power are the most important influencing factors. The best conditions for ultrasound application are a frequency of 20.4 kHz, power of 90 W, duration of 6.2 min and start time at 15.0 min. The FUC reached 71.75% after several minutes of sonication, which is 4.31% higher than the FUC of free flocculation. The results of E-SEM analysis showed significant differences among the microstructures of settled tailings (STs) after free flocculation and 17 and 20 kHz ultrasound treatment. Ultrasound at a frequency of 20 kHz has a more effective mechanical vibration and cavitation action and can therefore effectively break the polymer flocculant chains into shorter chains and promote the compaction of tailings and the release of water. The size distributions of the flocs before and after sonication also support this conclusion.

Codelivery of salinomycin and docetaxel using poly(D,L-lactic-co-glycolic acid)-poly(ethylene glycol) nanoparticles to target both gastric cancer cells and cancer stem cells.

Cancer stem cells (CSCs) in gastric cancer (GC) have been established recently as key therapeutic targets for the successful treatment of GC. Emerging evidence suggests that both CSCs and cancer cells should be eradicated to achieve optimal therapeutic efficacy. In the present study, salinomycin, which has been reported to kill CSCs, was used in combination with docetaxel, a chemotherapeutic drug that is used as first-line therapy in GC, to eradicate both GC stem cells (SCs) and cancer cells. Salinomycin and docetaxel were loaded separately into poly(D,L-lactic-co-glycolic acid)-poly(ethylene glycol) nanoparticles of ∼140 nm with a narrow size distribution, high drug loading, and sustained drug release. GC SCs were isolated by magnetic-activated cell sorting on the basis of CD44 expression as the CSC phenotype. CD44 GC SCs showed the characteristics of CSCs, including increased SC gene expression, tumorsphere formation capacity, and tumorigenicity in nude mice. We found that both salinomycin and salinomycin-loaded nanoparticles (salinomycin-NPs) could selectively eradicate GC SCs, as reflected by reduced tumorsphere formation capacity and the frequency of CD44 GC cells, whereas docetaxel and docetaxel-loaded nanoparticles (docetaxel-NPs) could significantly eradicate GC cells. In nude mice bearing GC xenografts, salinomycin-NPs and salinomycin significantly decreased the intratumor population of GC SCs. Notably, salinomycin-NPs combined with docetaxel-NPs suppressed tumor growth more effectively than did salinomycin combined with docetaxel, single salinomycin-NPs, or docetaxel-NPs. Therefore, salinomycin-NPs combined with docetaxel-NPs represent a promising strategy for the treatment of GC by eradicating both GC SCs and cancer cells.

The Comparison of Etomidate and Propofol Anesthesia in Patients Undergoing Gastrointestinal Endoscopy: A Systematic Review and Meta-Analysis.

INTRODUCTION: Etomidate and propofol played an important role in the sedation of patients undergoing gastrointestinal endoscopy. We conducted a systematic review and meta-analysis to compare their efficacy and safety. MATERIALS AND METHODS: PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials assessing the effect of etomidate versus propofol for the anesthesia of patients undergoing gastrointestinal endoscopy were included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. The primary outcomes were anesthesia duration and recovery time. Meta-analysis was performed using random-effect model. RESULTS: Six randomized controlled trials involving 1115 patients were included in the meta-analysis. Overall, compared with propofol, etomidate resulted in comparable anesthesia duration [standard mean difference (Std. MD)=-0.03; 95% confidence interval (CI), -0.16 to 0.10; P=0.66], recovery time (Std. MD=0.25; 95% CI, -0.42 to 0.92; P=0.47), mean arterial pressure at intubation (Std. MD=0.44; 95% CI, -0.26 to 1.15; P=0.21), heart pulse at intubation (Std. MD=0.93; 95% CI, -0.69 to 2.55; P=0.26), SPO2 at intubation (Std. MD=-0.52; 95% CI, -1.04 to 0.01; P=0.05), patient satisfaction [odds risk (OR)=0.42; 95% CI, 0.11-1.66; P=0.22], hypotension (OR=0.14; 95% CI, 0.02-1.22; P=0.07), changes of heart rate (OR=0.97; 95% CI, 0.61-1.53; P=0.88), nausea-vomiting (OR=2.02; 95% CI, 0.73-5.57; P=0.17), and the reduction in apnea or hyoxemia (OR=0.39; 95% CI, 0.24-0.64; P=0.0002), and injection pain (OR=0.03; 95% CI, 0.01-0.08; P<0.00001), but the increase in myoclonus (OR=8.54; 95% CI, 3.14-23.20; P<0.0001). CONCLUSIONS: Between etomidate and propofol, no significant difference was revealed regarding anesthesia duration, recovery time, mean arterial pressure at intubation, heart pulse at intubation, SPO2 at intubation, patient satisfaction, hypotension, changes of heart rate and nausea-vomiting. Compared with propofol, etomidate showed reduced apnea or hyoxemia, and injection pain, but with an increased myoclonus.