[Characterization of Metal Pollution of Regional Atmospheric PM2.5 and Its Sources Based on the PMF Model].

As important components of PM2.5, metal elements are extremely harmful to people and also have source specificity. Understanding the characteristics of PM2.5 metal pollution in the two different types of cities can help adjust the layout of regional industrial structure and improve the environment. PM2.5 samples during haze/non-haze periods were collected in Chengdu City and Renshou County. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the mass concentrations of eighteen metal elements in collected PM2.5 samples. The positive matrix factorization (PMF) model was used for source apportionment analysis for metal elements in PM2.5. The analysis showed that the ratio of trace elements from fugitive dust, motor vehicle emissions, and coal burning to the total elements is greater in Chengdu City than that in Renshou County. The proportion of trace elements from biomass combustion, industrial, and fuel sources in Renshou County is higher than that in Chengdu City. In addition, concentrations of Cd, As, and Cr in both areas exceeded the standards, indicating the occurrences of heavy metal pollution. During the haze period, the total concentrations of compositional metal elements in PM2.5 increased, although the rate was much lower than that for PM2.5. The ratios of elements between haze and non-haze periods ranged from 0.7 (Al) to 2.8 (Ba) in Chengdu City, and from 0.8 (Al) to 3.1 (Mn) in Renshou County. Among all metal elements, the increase rate for trace elements from coal burning and industrial activities was relatively large but small for those from fugitive dust, with the growth in trace elements from motor vehicles being modest. The results of this study indicated that the characteristics of pollution and source of metal elements in PM2.5 varied by economic scale, development mode, and industrial layout. In large cities such as Chengdu City, where economic development is mainly focused on tertiary industry, air pollution is mainly caused by transportation and urban construction, while in suburban area such as Renshou County, where secondary or heavy industry are the focus for economic development, the pollution is mainly affected by energy consumption and industrial production.

[Comparative Analysis of Pollution Characteristics of Carbonaceous Aerosol Components in the Atmosphere Between Urban and Suburban Areas].

To compare the pollution characteristics of carbonaceous aerosol components in the atmosphere between urban and suburban areas, Chengdu City and Renshou County were selected as study areas from which 88 samples of PM2.5 during haze and non-haze periods were collected and analyzed. Quantification of mass concentrations of PM2.5, carbonaceous aerosol components[organic carbon (OC), elemental carbon (EC), and secondary organic carbon (SOC)], along with correlation analysis of OC and EC, and principal component analysis (PCA) of carbon components were carried out. The results show that pollutant concentrations during the haze period were higher than those during the non-haze period. The OC and EC for Chengdu City and Renshou County were positively correlated, with their correlation coefficients during the non-haze period higher than those during the haze period. The ratios of SOC/PM2.5 in Renshou County were higher than those in Chengdu City during the haze period. This indicates that secondary aerosols play a more important role in haze formation in Renshou than in Chengdu City. In contrast, the proportion of secondary aerosols during the non-haze period in Chengdu City was significantly higher, indicating that direct emissions are still the main cause of air pollution in Chengdu City. PCA results showed that PM2.5 formation in both Chengdu City and Renshou County was mainly due to coal burning, vehicle operation, and biomass burning.

Association between serum leptin levels and breast cancer risk: An updated systematic review and meta-analysis.

BACKGROUND: Many studies have indicated that leptin is correlated with breast cancer occurrence and tumor behavior. However, this issue remains controversial. Therefore, we conducted an updated meta-analysis to investigate the role of leptin in breast cancer. METHODS: We performed a systematic literature search and identified relevant papers up to 1 September 2017. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to evaluate effect sizes. RESULTS: Thirty-five eligible studies were included in the current meta-analysis. Serum leptin levels were related to breast cancer risk as demonstrated by calculations of the overall SMD = 0.46 (95% CI = 0.31-0.60, I = 93.5%). A subgroup analysis of BMI identified an association between breast cancer and serum leptin levels in patients who are overweight and obese (overweight: SMD = 0.35, 95% CI = 0.13-0.57, I = 88.1%; obesity: SMD = 1.38, 95% CI = 0.64-2.12, I = 89.6%). Additionally, menopausal status subgroup analysis revealed a significant association in postmenopausal women (SMD = 0.26, 95% CI = 0.12-0.40, I = 77.9%). Furthermore, we identified a significant association between breast cancer and serum leptin levels in Chinese women (SMD = 0.61, 95% CI = 0.44-0.79, I = 40.6%). CONCLUSION: The results of this meta-analysis suggested that leptin could be a potential biomarker for breast cancer risk in women, especially overweight/obese or postmenopausal women. Therefore, it may be useful for identifying subjects with a high risk for breast cancer who may benefit from preventive treatments.

Effects of different stocking density and diet on development of Bufo gargarizans tadpoles / 中国中药杂志

The effects of four different stocking densities and five different diets on the growth of Bufo gargarizans tadpoles were studied to determine the optimum stocking density and diet. For stocking density experiment, the tadpoles were fed respectively at different density of 200, 500, 1 000 and 2 000 tadpoles per square meter. For diet experiment, the tadpoles were divided into five groups fed respectively with five different diets. The body weight, snout-vent length and tail length were measured every seven days, and mortality was recorded. The results showed that: the survival rates of tadpole before metamorphosis and after metamorphosis were from 68.7% to 96.3% and from 5.7% to 36.0%, respectively; the optimum stocking density is 1 000 tadpoles per square meter for the stocking density had no effect on the survival rate of tadpole before metamorphosis, and the tadpoles had the relative large body weight and survival numbers in 1000 tadpoles per square meter; the diet Ⅱ(37.9% crude protein and 5.7% crude fat), Ⅳ (25.1% crude protein and 4.0% crude fat), and Ⅴ (egg yolk) were all the optimum diets for the diet had no effect on the survival rate of tadpole before metamorphosis and the tadpoles fed with three kinds of diet above had relatively large body weight, and one of these three diets based on their availability and cost should be adopted during breeding period.

[A new method for the preparation of potassium ferrate and spectroscopic characterization].

Calcium hypochlorite was used as the raw material for preparation of the high purity potassium ferrate. The study includes the effects of reaction temperature, recrystallization temperature, reaction time, Ca(ClO)2 dosage, and the amount of calcium hypochlorite on the yield. It was determined that when the reaction temperature was 25 degrees C, recrystallization temperature 0 degree C and reaction time 40 min, the yield was more than 75%. The purity was detected by direct spectrophotometric method to be more than 92%. The product was characterized by infrated spectrum(IR), X-ray diffraction (XRD) and ultraviolet spectrum (UV) methods and proved to be potassium ferrate that was prepared by calcium hypochlorite as the raw material.

[Removal of arsenic (II) by ferrate oxidation-coagulation from drinking water].

Ferrate is multi-function agent in water treatment and shows great oxidizing ability and excellent purifying effect. This experiment evaluated the performance of ferrate for arsenic removal. Experimental results show that the best rate of ferrate and arsenic (III) is 15:1, the efficiency of As removal can be achieved 98%, and the residual concentration of As3 + is < 0.05 mg/L. The optimum pH is 5.5 to approximately 7.5. The oxidative and coagulation time is 10 min and 30 min respectively. The salinity and hardness did not interfere with removal arsenic. This method is easy, very effective comparing with ferric method and KMnO4-Ferric method.