Highly-efficient and sequential recovery of rare earth elements, alumina and silica from coal fly ash via a novel recyclable ZnO sinter method.

A novel sinter method using ZnO as the activator instead of the conventional Na2CO3/CaCO3, (NH4)2SO4, and K2S2O7 was developed to achieve efficient sequential extraction of rare earth elements (REEs), alumina (Al), and silica (Si) from coal fly ash (CFA). Up to 93.3% Si, 87.1% REEs (70.7% Ce, 82.5% La, 83.2% Gd, 87.1% Nd, 62.3% Dy, and 81.7% Y), and 92.9% Al were extracted from CFA, respectively. Moreover, 93.1% of the ZnO activator was efficiently recycled, and the yield of red mud was only 14.9%. X-ray diffraction (XRD) and X-ray absorption near edge structure (XANES) results showed that the speciation transformation of Al/Si during CFA/ZnO roasting was as follows: mullite, quartz, amorphous Al2O3, and SiO2 → Zn0.75Al1.5Si1.5O6, kyanite and willemite → gahnite and quartz/cristobalite solid solutions. The change in the REEs occurrence mode hinted at the migration of most REEs in aluminosilicates forms with Si during roasting, and disassociation with Si into the acid-soluble form after alkali leaching. These results indicate that the coupling of Al-Si-REE in CF was broken by this ZnO sinter method, promoting the sequential and efficient extraction of REEs, Al, and Si from CFA. This study provides a green and efficient strategy for element recovery from CFA, substantially reducing residues and favoring REEs concentration.

Di(2-ethylhexyl)phthalate induces reproductive toxicity via JAZF1/TR4 pathway and oxidative stress in pubertal male rats.

Di(2-ethylhexyl)phthalate (DEHP) is a typical endocrine-disrupting chemical and reproductive toxicant. Although previous studies have attempted to describe the mechanism by which DEHP exposure results in reproductive dysfunction, few studies focused on puberty, a critical period of reproductive development, and the increased susceptibility to injury in adolescents. To elucidate the mechanism underpinning the testicular effects of DEHP in puberty, we sought to investigate the JAZF1/TR4 pathway in the testes of pubertal rats. Specifically, we focused on the role of the JAZF1/TR4 pathway in male reproduction, including the genes JAZF1, TR4, Sperm 1, and Cyclin A1. In the present study, rats were exposed to increasing concentrations of DEHP (0, 250, 500, and 1000 mg/kg/day) by oral gavages for 30 days. Then we assayed testicular zinc and oxidative stress levels. Our results indicated that DEHP exposure could lead to oxidative stress and decrease the contents of testicular zinc. Additionally, significant morphological changes and cell apoptosis were observed in testes exposed to DEHP, as identified by hematoxylin and eosin staining and the terminal deoxynucleotidyl transferase-mediated nick and labeling assay. By measuring the expression levels of the above relevant genes by qPCR, we found the DEHP-induced increased expression of JAZF1 and decreased expression of TR4, Sperm 1, and Cyclin A1. Therefore, we have demonstrated that in vivo exposure to DEHP might induce reproductive toxicity in pubertal male rats through the JAZF1/TR4 pathway and oxidative stress.

[Analysis of therapeutic effects of rural patients with hypertension by combination administration of low dosage of hydrochlorothiazide and nitrendipine].

OBJECTIVE: To evaluate the therapeutic effects of combination administration of hydrochlorothiazide and nitrendipine at low dosage in the treatment of rural hypertension patients. METHODS: By the method of cluster random sampling, 5292 primary hypertension patients from Fuxin, Liaoning Province were divided into health education group (control group) and drug intervention group in June 2006. The drug intervention group were treated with hydrochlorothiazide, nitrendipine and captopril by stepwise approach and we observe the antihypertensive effect of drug and the effect on the onset of stroke. RESULTS: The average follow-up time was 15 months. At last, 308 patients were lost to follow-up (the lost follow-up rate was 5.8 percent). The 4984 in cohort, including 2530 of intervention group and 2454 of control group, had examination of all indicators. Through health education and drug intervention, the average blood pressure in drug intervention group decreased by 16.1/9.4 mm Hg (1 mm Hg = 0.133 kPa) while the average blood pressure in control group decreased by 6.7/3.5 mm Hg. The control rate of blood pressure in drug intervention group was higher than control group (33.1% vs. 15.1%, P < 0.001). Through drug intervention, the morbidity risk of nonfatal stroke in drug intervention group decreased by 57.3% compared to control group, the total morbidity risk of stroke decreased by 59.4%. The results had significant statistical difference. And, the morbidity of severe hypopotassaemia (K(+) < 3.0 mmol/L) and diabetes mellitus had no significant statistical difference between two groups. CONCLUSIONS: The low-cost antihypertensive program based on thiazide had good antihypertensive effect, high safety and good cost-effect ratio. The program could be used in rural areas of China.

[Performance of slow-release organic carbon-source (SOC) materials for in-situ biological denitrification in groundwater].

As lack of electron donor (carbon source) is a key problem of in-situ denitrification in groundwater, slow-release organic carbon-source (SOC) materials were produced as appropriate electron donor in denitrification PRB. GPVAS and GEPVAS series were manufactured by blending starch and PVA together, with alpha-amylase as the additive, and their performance was detected through SEM and static batch experiments. The results showed that PVA formed the framework filling with starch molecule, and the carbon releasing process followed the law of second order kinetics. Equilibrium concentration of COD (c(m)) and release rate coefficient (k) were key factors of kinetics evaluation. Both c(m) and k of GPVAS-40 were the lowest. The influence of alpha-amylase to the performance of SOC materials was remarkable. The c(m) values would ascend rapidly with augmenting of alpha-amylase content, while the releasing speed rose when amylase activity was lower than 0.03 U/g and then decreased. Consequently, the releasing process was controllable through changing the content of starch and activity of alpha-amylase to meet needs of different situations and pollution of groundwater and improve the effect of in-situ nitrate removal.