Erythrocyte membrane n-3 PUFA are inversely associated with breast cancer risk among Chinese women.

The relationship between erythrocyte membrane n-3 PUFA and breast cancer risk is controversial. We aimed to examine the associations of erythrocyte membrane n-3 PUFA with odds of breast cancer among Chinese women by using a relatively large sample size. A case-control study was conducted including 853 newly diagnosed, histologically confirmed breast cancer cases and 892 frequency-matched controls (5-year interval). Erythrocyte membrane n-3 PUFA were measured by GC. Logistic regression and restricted cubic spline were used to quantify the association between erythrocyte membrane n-3 PUFA and odds of breast cancer. Erythrocyte membrane α-linolenic acid (ALA), docosapentaenoic acid (DPA) and total n-3 PUFA were inversely and non-linearly associated with odds of breast cancer. The OR values (95 % CI), comparing the highest with the lowest quartile (Q), were 0·57 (0·43, 0·76), 0·43 (0·32, 0·58) and 0·36 (0·27, 0·49) for ALA, DPA and total n-3 PUFA, respectively. Erythrocyte membrane EPA and DHA were linearly and inversely associated with odds of breast cancer ((EPA: ORQ4 v. Q1 (95 % CI) = 0·59 (0·45, 0·79); DHA: ORQ4 v. Q1 (95 % CI) = 0·50 (0·37, 0·67)). The inverse associations were observed between ALA and odds of breast cancer in postmenopausal women, and between DHA and oestrogen receptor+ breast cancer. This study showed that erythrocyte membrane total and individual n-3 PUFA were inversely associated with odds of breast cancer. Other factors, such as menopause and hormone receptor status, may warrant further investigation when examining the association between n-3 PUFA and odds of breast cancer.

Serum flavin mononucleotide but not riboflavin is inversely associated with the risk of colorectal cancer.

Vitamin B2 is essential for DNA methylation, stability and repair, which may influence the development and pathogenesis of several cancers. However, data regarding the associations of circulating vitamin B2 with colorectal cancer risk are limited. The purpose of this study was to investigate the associations between serum vitamin B2 and colorectal cancer risk, particularly among participants with different serum levels of vitamin B6 or folate. A hospital-based case-control study, including 1009 colorectal cancer cases and 1182 controls matched by age and sex, was conducted in Guangdong Province, China. Vitamin B2 including riboflavin and flavin mononucleotide (FMN), the vitamin B6 indicator pyridoxal-5'-phosphate (PLP) and folate in serum samples were measured by ultra-high-performance liquid chromatography-tandem mass spectrometry. Vitamin B2 sum was calculated as the sum of riboflavin plus FMN. A significant inverse association was observed between serum FMN, but not serum riboflavin or vitamin B2 sum, and colorectal cancer risk. The adjusted odds ratio (OR) and 95% confidence interval (95% CI) of serum FMN, by comparing the highest with the lowest quartile, was 0.63 (0.46-0.85, Ptrend = 0.001). Stratified analysis by serum PLP and folate levels indicated that serum FMN was inversely associated with colorectal cancer risk among participants with lower serum PLP or higher folate levels. This study added supporting data to the limited evidence that vitamin B2 could play a preventive role in colorectal carcinogenesis among the Chinese population, primarily by FMN. Individuals with a lower PLP level or an adequate folate level could be more sensitive to the protective role of vitamin B2.

[Temporal Response of Subterranean Karst Stream Hydrochemistry to Urbanization].

The hydrochemical responses of underground rivers to urbanization were studied using a 25-year groundwater observation dataset and remote sensing. We found that as urbanization progresses, the mineralization degree of underground rivers gradually increases; time-series data for dominant hydrochemical indicators changed from HCO3·SO4-Ca·Mg during the dry season and HCO3-Ca·Mg during flood season to HCO3·Cl-Ca, HCO3·SO4-Ca, HCO3-Ca, and HCO3·SO4-Ca·Mg. Influenced by surface precipitation input, the groundwater chemistry of underground rivers varies greatly during the dry season and the flood season. Prior to urbanization,[Mg2+]/[Ca2+] and[HCO3-]/[SO42-] molar ratios are affected by water-rock interactions, agricultural activities, and acid rain infiltration, the average values of which were 0.86 and 29.34, respectively. After urbanization, agricultural activities and the contribution from acid rain decreased gradually. During the periods 1990-1995, 1996-2010, and 2011-2015, the main sensitive geochemical cations were Ca2+, Mg2+, Na+, and NH4+, and the main anions were HCO3-, HCO3-, and SO42-, and Cl-. The hydrochemical response of underground rivers to urbanization was characterized by clear temporal phases.

[Rock Weathering Characteristics and the Atmospheric Carbon Sink in the Chemical Weathering Processes of Qingshuijiang River Basin].

Carbon sink produced during rock weathering is critical to global carbon cycles. In this work, the major ion chemistry and ion sources of Qingshuijiang River Basin were investigated. The principal component analysis, mass balance approach and deduction method were applied for estimating the weathering rate and atmospheric CO2 consumption via the chemical weathering of rocks. The results demonstrated that the chemical weathering of carbonate and silicate rocks within the drainage basin was the main source of the dissolved chemical substances in the Qingshuijiang River Basin, prior to carbonate rock weathering. Some 58.28% of the total dissolved chemical substances were derived from the chemical weathering of carbonate rock, 17.38% from the dissolution of silicate rock, and 17.74% from atmospheric CO2 contribution rates. The chemical weathering rate of this catchment was estimated to be 109.97t·(km2·a)-1, which was comparable to Wujiang River Basin, but higher than the average of global rivers. Furthermore, the atmospheric CO2 consumption rate was estimated to be 7.25×105 mol·(km2·a)-1. The CO2 flux consumed by the rock chemical processes within this catchment was 12.45×109 mol·a-1, of which about 63.13%(7.86×109 mol·a-1) was resulted from carbonate weathering and 36.87%(4.59×109 mol·a-1) from silicate weathering. The CO2 consumed by rock chemical weathering in the Qingshuijiang River reduced the atmospheric CO2 level and constituted a significant part of the global carbon budget. Correlation and spatial distribution analysis of SO42-, F-, NO3- showed that anthropogenic activities contributed remarkably to dissolved solutes and associated CO2 consumption worldwide, and anthropogenic inputs probably contributed some 4.87% to the dissolved solutes in the Qingshuijiang River.

[Hydrochemical Characteristics and Sources of Qingshuijiang River Basin at Wet Season in Guizhou Province].

According to the ion content and chemical characteristic analysis of Qingshuijiang River water during wet season, the result shows that the chemical composition of the river water is dominated by Ca2+, HCO(3-); Mg2+, and SO4(2-). The TDS concentration (213.96 mg · L(-1)) is significantly higher than the average value of rivers worldwide. Seawater correction approach (Cl(-) normalized seawater ratios) was applied to estimate the contribution proportions of local precipitation to the solutes, and it is found that the contribution ratio of precipitation (2.23%) is lower than the average value (3%) of global catchments. Furthermore, Gibbs graph combining major ion element ratio analysis indicates that the catchment hydrochemistry is mainly originated from carbonate rock weathering, which becomes increasingly distinct as the river goes downstream. Both carbonic acid and sulfuric acid play crucial roles in the chemical weathering. Ion source analysis demonstrates that Ca2+, Mg2+, HCO3- are mainly derived from chemical weathering of carbonate mineral (Dolomite and Calcite); Na+, K+ and Cl- are primarily contributed by silicate mineral weathering; SO4(2-) and NO3- stemmed are mainly from acid atmospheric deposition and from urban sewage input. Anthropogenic analysis suggests that the chemical composition of Qingshuijiang River is greatly impacted by the upriver industrial and mining enterprises activities.

[Isotopic composition and isotope tracing of sulfur in atmospheric precipitation at the head area of the Three Gorges Reservoir, China].

Rainwater samples were collected in the head area of the Three Gorges Reservoir from June 2009 to July 2010. The SO4(2-) content and the characteristics of sulfur isotopic composition were determined. The results showed that the concentrations of SO4(2-) ranged from 31.4-668. 1 micromol x L(-1) with a weighted average of 161.9 micromol x L(-1), whereas the variation of delta34S values for SO4(2-) ranged from -2.14 per hundred to 6.07 per hundred with an annual average of 2.06 per hundred +/- 1.97 per hundred. Significant seasonal variations were found in the SO4(2-) content, which were higher in winter and spring and lower in summer and autumn. The delta34S values for SO4(2-) measured in winter were much higher than those in the other seasons. Analysis of the delta34S values showed that the biogenic sulfur might have significant contribution to the acidity of rainwater, especially in summer and autumn.

[Chemical characterization of rainwater in a karst rural site: a case study of Puding, China].

Rainwater samples of a karst rural site in Puding County, Guizhou Province, China over a period of one year (2008) were collected and the major ion concentrations were measured. The pH of samples varied from 4.6 to 7.1 and volume-weighted mean was 5.7. Ca2+ was the dominant cation in rainwater and volume-weighted mean was 303.2 microeq x L(-1). It accounted for 34%-88% of the total cations in the studied rainwater samples. SO4(2-) and NO3- were the main anions, and their volume-weighted mean were 281.2 microeq x L(-1) and 69.9 microeq x L(-1), respectively. The sum of SO4(2-) and NO3- accounted for 63%-93% of the total anions in the studied rainwater samples. Investigations of fractional acidity (FA), neutralization factors (NF), and correlation coefficients among ionic constituents indicated that high pH values were controlled by the neutralization caused by the alkaline materials but not by the absence of acidic materials. Studies of the origins of major ions showed that Ca2+ was from the terrestrial source, e. g. crustal dust and human activities, and NH4+ and K+ were from the soils and human acidities, while SO4(2-) and NO3- were mainly originated from anthropogenic sources.