Cytotoxicity and cell membrane depolarization induced by aluminum oxide nanoparticles in human lung epithelial cells A549

The cytotoxicity of 13 and 22 nm aluminum oxide (Al₂O₃) nanoparticles was investigated in cultured human bronchoalveolar carcinoma-derived cells (A549) and compared with 20 nm CeO₂ and 40 nm TiO₂ nanoparticles as positive and negative control, respectively. Exposure to both Al₂O₃ nanoparticles for 24 h at 10 and 25 µg mL^?1 doses significantly decreased cell viability compared with control. However, the cytotoxicity of 13 and 22 nm Al₂O₃ nanoparticles had no difference at 5–25 µg mL^?1 dose range. The cytotoxicity of both Al₂O₃ nanoparticles were higher than negative control TiO₂ nanoparticles but lower than positive control CeO₂ nanoparticles (TiO₂ < Al₂O₃ < CeO₂). A real-time single cell imaging system was employed to study the cell membrane potential change caused by Al₂O₃ and CeO₂ nanoparticles using a membrane potential sensitive fluorescent probe DiBAC₄(3). Exposure to the 13 nm Al₂O₃ nanoparticles resulted in more significant depolarization than the 30 nm Al₂O₃ particles. On the other hand, the 20 nm CeO₂ particles, the most toxic, caused less significant depolarization than both the 13 and 22 nm Al₂O₃. Factors such as exposure duration, surface chemistry, and other mechanisms may contribute differently between cytotoxicity and membrane depolarization.     

The effects of bisphenol A on sex hormone levels of F0 female rats and F1 male rats during weaning period

The effects of bisphenol A (BPA) were examined on sex hormones of F1 generation male rats during weaning period. Female rats were exposed to BPA from day 0 after pregnancy to the weaning period at doses of 50, 100, or 200 mg kg^?1. The sex hormone levels of F1 generation male rats were determined. This study shows that F0 generation female rats fed with 200 mg kg^?1 BPA had a significantly higher serum prolactin (PRL) levels at the end of weaning. Significantly higher levels of serum estradiol (E₂) were also found in female rats fed 100 or 200 mg kg^?1 BPA. Serum levels of E₂ in F1 male generation rats were higher in treatment groups compared to control groups while serum testosterone (T) levels were lower. Follicle stimulating hormone (FSH) in F1 generation rats fed 200 mg kg^?1 was markedly decreased. The relative testicular weights were significantly less in 100 and 200 mg kg^?1 BPA groups. BPA was found to alter the sex hormone levels in F1 male rats during weaning period and thus disrupted endocrine functions.     

Effects of chronic bisphenol A exposure on hepatic antioxidant parameters in medaka (Oryzias latipes)

Bisphenol A (BPA), the plastic monomer and plasticizer with well-known endocrine-disrupting chemical properties, is widely present in the aquatic environment, but little is known regarding hepatic toxicity in fish. This study assessed the effects of chronic exposure to BPA on the antioxidant defense system of Japanese medaka liver. Fish were exposed to sub-lethal concentrations of BPA (0.1, 1, 10, 100, or 1000?µg?L^?1) for 60 days. Antioxidant parameters were determined and compared with controls. The results showed that the activities of catalase (CAT), superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and the content of reduced glutathione were all induced at 10?µg?L^?1 BPA after 60 days. Further, hepatic CAT was sensitive to BPA at 1?µg?L^?1 concentration. In conclusion, CAT may serve as a potential early biomarker of BPA exposure in aquatic environment.     

铁改性掺氮碳纤维活化过一硫酸盐降解双酚A

通过静电纺丝制备了 Fe和N掺杂改性的碳纳米纤维(Fe-N-CNF),研究了该催化剂活化过一硫酸盐(PMS)降解双酚A(BPA)的性能.以聚丙烯腈为前驱体通过添加FeCl3、尿素、NH4Cl、均苯四甲酸二酐等配制溶胶进行静电纺丝,预氧化并高温碳化后获得Fe-N-CNF,研究了 Fe-N-CNF投加量、PPMS投加量、溶...     

Employee reactivity and adaptation to observation on the job

In the course of studying police dispatchers, five observers recorded the reactions of the employees (N = 37) to their presence throughout the work shift on three separate occasions. Four major research questions were considered: (a) extent of reaction, (b) relationship between interactions with the observer and changes in employees' work activities, (c) independence of verbal and nonverbal behavioral reactions, and (d) adaptation. On average, subjects or other employees initiated 10 interactions per hour with observers. These interactions were classified as subject-initiated (a) verbal, content related to research procedures; (b) verbal, non-research-related in content; (c) nonverbal only or (d) other employee-initiated verbal comment. Interaction with the observer was not related to the amount of work the subject did. Subjects' nonverbal and verbal responses were unrelated to each other as well as to the verbal responses of other employees. A priori expectations concerning adaptation to observation were tested with a 3 × 3 (segment by day) repeated-measures factorial design. Significant adaptation (P < 0·01) occurred within and between days in subjects' comments about research procedures and all comments from other employees. However, other behaviors showed with no evidence of adaptation or actual increases. The implications of these findings for measuring reactivity and deciding when adaptation has occurred are discussed.     

攀钢煤化工厂废水处理系统优化改造

攀钢煤化工厂废水处理系统于2008年3月优化改造,采用A/O2+生物接触氧化工艺对废水进行处理.改造后系统运行处理能力和稳定性均得到提高,生化系统出水水质稳定,氨氮≤15 mg/L,COD≤150 mg/L.     

Effects of probiotic bacteria on the bioaccessibility of aflatoxin B1 and ochratoxin A using an in vitro digestion model under fed conditions

In the present study, we aimed at determining the release of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA) from different food products in the gastro-intestinal tract in the absence and presence of probiotics, a possible adsorbent. The average bioaccessibility of AFB₁ and OTA without probiotics was about 90%, and 30%, respectively, depending on several factors, such as food product, contamination level, compound and type of contamination (spiked versus naturally contaminated). The six probiotic bacteria showed varying binding capacity to AFB₁ and OTA depending on the bacterial strain, toxin studied, type of food and contamination level. A reduction to a maximum of 37% and 73% as observed for the bioaccessibility of AFB₁ and OTA in the presence of probiotic bacteria, respectively. This is the first report on the effect of probiotic bacteria on reducing the fraction of mycotoxins available for absorption in the gastrointestinal tract from different food products.     

A3钢在不同化学清洗液体中的腐蚀失重分析

在A3钢腐蚀试验中,为完全清除腐蚀样品表面的腐蚀产物,必须采用化学清洗的方法.在比较不同的化学清洗效果之后,得出以下实验结果：柠檬酸铵-氨水系列对空白样的腐蚀很小,几乎为零,但是该溶液对腐蚀样品的腐蚀产物清洗效果不好;硫酸-有机缓蚀剂酸洗液对金属的空白腐蚀较重,使实验误差较大;有机缓蚀剂-盐酸系列对空白样的腐蚀适中,对腐蚀样品的腐蚀产物的清除也较完全.