Long-term excess body fat in adulthood and the risk of pre- and postmenopausal breast cancer in Chinese women.

PURPOSE: This study aimed to investigate the association between long-term excess body fat and breast cancer risk by studying adult weight gain together with the subsequent weight fluctuations. METHODS: Weight gain measure in three different time periods in adulthood of 1500 participants was collected in a case-control study of Western China. Logistic regression models were used to estimate odds ratios and 95% CIs. RESULTS: The increased risk of postmenopausal BC was associated with adult weight gain at 5 years and at 10 years before enrollment (OR 1.24, 95% CI 1.03-1.49 per 5 kg increase; OR 1.40, 95% CI 1.14-1.70 per 5 kg increase) but was not associated with adult weight gain at enrollment (OR 0.97, 95% CI 0.81-1.16 per 5 kg increase). Only a positive association was observed in premenopausal women who had gained > 5.0 kg at 10 years before enrollment (OR 1.61, 95% CI 1.10-2.35). Women who had gained > 5.0 kg at 10 years before enrollment and continued to gain during the subsequent 5 years had the highest postmenopausal BC risk (OR 3.34, 95% CI 1.58-7.08). CONCLUSION: Adult weight gain at 5 years and 10 years before enrollment are more closely associated with postmenopausal BC risk than adult weight gain at enrollment in Western China. Controlling body weight as early as possible throughout adulthood to keep weight gain not more than 5.0 kg is particularly necessary for Chinese women.

A comparative study on the dissolution and stability of beudantite and hidalgoite at pH 2-12 and 25-45 °C for the possible long-term simultaneous immobilization of arsenic and lead.

Beudantite and hidalgoite were synthesized and characterized to investigate their possible immobilization for arsenic and lead in acidic and oxidizing environments by a long-term dissolution. The synthetic beudantite [Pb0.35(H3O)0.40Fe3.09(AsO4)0.37(SO4)1.63(OH)6.00] was spherulitic pseudo-cubic crystals with nearly smooth surface. The synthetic hidalgoite [Pb0.72(H3O)2.71Al2.26(AsO4)0.93(SO4)1.07(OH)6.00] was well-formed pseudo-cubic, pseudo-cuboctahedral or pseudo-octahedral crystals. During the beudantite dissolution, the constituents were dissolved preferentially in the order of SO42- > AsO43- > Pb2+ > Fe3+ in the early 24 h and SO42- > AsO43- > Fe3+ > Pb2+ after 24 h; the dissolved concentrations exhibited a minimum of 0.0027-0.0030 mg/L Pb and 0.0248-0.0250 mg/L As. During the hidalgoite dissolution, the constituents were dissolved preferentially in the order of Pb2+ > SO42- > AsO43- > Al3+ at initial pH < 4 or AsO43-,SO42- > Al3+ > Pb2+ at initial pH > 4; the dissolved concentrations showed a minimum of 0.0055-0.0061 mg/L Pb and 0.0750-0.0810 mg/L As. From the data of the dissolution at initial pH 2 and 25 °C for 270-330 d, the ion-activity products [logˍIAP] were estimated to be -94.18 ± 0.04 for the beudantite and -73.82 ± 0.11 for the hidalgoite, respectively. The concentrations of Pb and As released in the beudantite dissolution were always lower than in the hidalgoite dissolution and arsenate appeared to be much more soluble than Pb. Beudantite was more effective for the immobilization of As and Pb than hidalgoite.

[Removal of Pb2+ from Aqueous Solution by Magnesium-Calcium Hydroxyapatite Adsorbent].

A novel magnesium-calcium hydroxyapatite adsorbent was prepared by the Sol-gel method with different proportions of Mg/(Ca+Mg) using Mg2+ as doped ions, and the removal characteristics and process mechanism of Pb2+ on the magnesium-calcium hydroxyapatite in an aqueous solutions were studied. The results show that the surface of the adsorbent is composed mainly of a hydroxyphosphonite compound[Pb10(PO4)6(OH)2], The morphological characteristics of the magnesium-calcium hydroxyapatite adsorbent surface was investigated as crystal structure changes from short rods to needle structures according to scanning electron microscopy (SEM). Testing at a temperature of 25℃ and pH of 5 showed that the adsorption of Pb2+ by magnesium-calcium hydroxyapatite reached equilibrium within 720 min. The adsorption capacity was determined to be 813.17 mg·g-1 at a dosage of 0.6 g·L-1. The thermodynamic test results of ΔGθ<0, ΔSθ>0, and ΔHθ>0 indicated that the adsorption process of Pb2+ by magnesium-calcium hydroxyapatite is a spontaneous process with endothermic reaction and entropy increments, and higher temperatures were considered be favorable for adsorption at a range of 25-45℃. The adsorption could be effectively described by a pseudo-second-order kinetic equation. The equilibrium data were found to follow the Langmuir adsorption model. Material characterization and adsorption tests showed that surface complexation and dissolution-precipitation were the main mechanisms for the removal of Pb2+ by magnesium-calcium hydroxyapatite in an aqueous solution.