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We report on a study of magnetism of Fe-doped ZnO powders and tablets synthesized via the solid-state reaction route. The X-ray diffraction results indicate that the solid solubility of Fe in ZnO was less than 1%. When the concentration of Fe was more than 2%, a second phase of ZnFe 2 O 4 was detected. All samples were ferromagnetic in the room temperature and the Hall effect was observed. Calculations based on the density functional theory (DFT+U) indicated two origins for the observed ferromagnetism. The first source is considered to occur due to the second phase of the inverse spinel-type ZnFe 2 O 4 where the antiferromagnetic states of the Fe 2 Zn 14 O 16 system were preferred through Fe 2+ O 2− Fe 2+ or Fe 3+ O 2− Fe 3+ bonding. The second appears to originate from the ferromagnetic states of the Fe 2 Zn 14 O 16 system with the Fe 3+ O 2− Fe 2+ bond. The bond is suggested to form due to the double exchange interaction with the Fe 2+ and Fe 3+ ions substituting the Zn 2+ ions in the ZnO lattice, yielding an intrinsic ferromagnetic oxide semiconductor.

Cigarette smoking is a risk factor in the developing of various cancers including breast tumors. There are more than 60 chemical carcinogens in the cigarette smoke; 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) being one of the strongest tobacco-specific carcinogens. In this study, we demonstrated that NNK rapidly activated ERK1 and ERK2 MAP kinases and stimulated proliferation in human normal mammary epithelial cells. MEK1/2 specific inhibitor UO126 completely blocked NNK-induced ERK1/2 activation and cell proliferation, whereas nicotinic receptor nAchR antagonist mecamylamine partially and the selective α(7)-nAchR antagonist α-bungarotoxin essentially inhibited the NNK-induced ERK1/2 activation and cell proliferation. Surprisingly, receptor tyrosine kinase inhibitor genistein, the selective β(1)-adrenergic antagonist atenolol, and the selective β(2)-adrenergic antagonist ICI118.551 had a strong inhibitory effect on ERK1/2 activation and cell proliferation induced by NNK. These results suggest that there are at least two different routes in activating ERK1/2 by NNK. One is through nicotinic receptor α(7)-nAchR to MEK1/2; the other is from β(1)/β(2)-adrenergic transactivation of tyrosine kinase containing receptor(s) to MEK1/2. In human cancer mammary epithelial cell lines, we found that ERK MAPK signaling pathway was deregulated: (1) ERK1/2 was constitutively activated at various levels; (2) ERK1/2 was further significantly activated in response to NNK induction; (3) UO126 partially or totally failed to inhibit ERK1/2 activation induced by NNK; (4) The expression levels of ERK1/2 in the cancer cell lines were much higher than those in the normal mammary epithelial cells. The tobacco-specific carcinogen NNK showed a strong proliferative effect on human normal and cancer mammary epithelial cells; the proliferation multitudes of these cells are well correlated with the activation levels of ERK1/2 MAP kinases.

To investigate the prevalence and causes of blindness and moderate and severe visual impairment among adults aged ≥ 50 years in Longyao County, Hebei Province, China.It was a population-based cross-section study.Geographically defined cluster sampling was used in randomly selecting 5527 individuals aged ≥ 50 years in Longyao County. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. All participants were enumerated through village registers followed door-to-door visits.Eligible individuals were invited to receive visual acuity measurement and eye examination. Prevalence of blindness and moderate and severe visual impairment was calculated according to different age, gender or education. And the reasons of blindness were analyzed.Statistical analyses were performed using Stata/SE Statistical Software, release 9.0. Chi-square test was used to investigate the association of age, gender and education with presenting and best corrected visual acuity.Five thousands five hundreds and twenty-seven individuals were enumerated and 5051 persons were examined, the response rate was 91.39%. Based on the criteria of World Health Organization visual impairment classification in 1973, the prevalence of blindness and moderate and severe visual impairment defined as best corrected visual acuity was 1.05% (53/5051) and 3.46% (175/5051) respectively. The prevalence of blindness and moderate and severe visual impairment defined as presenting visual acuity was 1.48% (75/5051) and 7.94% (401/5051) respectively. The prevalence of blindness and moderate and severe visual impairment was higher in aged (trend χ(2) = 897.27, P = 0.000) , female (χ(2) = 30.32, P = 0.000), illiterate (trend χ(2) = 83.20, P = 0.000) persons. Cataract was still the first leading cause of blindness. Un-corrected refractive error also was the main cause of visual impairment.The prevalence of blindness and moderate and severe visual impairment is relatively lower among China Nine Province Survey. The first leading cause of blindness and visual impairment is still cataract.