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Bi1-xMgxFeO3 (BMFO, x = 0, 0.02, 0.04, 0.06 and 0.08) multiferroic films were directly synthesized on flexible stainless steel (FSS), save the bottom electrode process, by means of sol&ndash, gel spin-coating technology. The effects of different bending conditions on ferroelectric, dielectric and leakage-current properties of BMFO films were investigated. The leakage-current densities of BiFeO3 (BFO, x = 0) and BMFO (x = 0.06) films were 5.86 &times, 10&minus, 4 and 3.73 &times, 7 A/cm2, which shows that the BMFO (x = 0.06) has more than three orders of magnitude lower than that of BFO film. The residual polarization (2 Pr) can be enhanced from 120 to 140 &mu, C/cm2. The proper doping of Mg in BiFeO3 film could provide an effective method for reducing the leakage-current values as well as boosting the ferroelectric properties. In this study, the leakage-current mechanism of low electric field and high electric field of BMFO film is analyzed and established. In addition, the flexible BMFO film maintains practical ferroelectric and leakage-current properties at retention time of 106 s under different symmetry bending conditions. These results indicate that the BFMO film will be very practical in opto-electronic and storage device applications.

Obstructive sleep apnea-hypopnea syndrome (OSAHS), a high incidence, potentially dangerous sleep-disordered breathing disorder, which with the important pathophysiological mechanism of chronic intermittent hypoxia (CIH) in patients. Hypoxia inducible factor -1 alpha (HIF-1α), as an important transcription factor in the development of hypoxia, HIF-1α activation encodes transcription of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) genes. We selected 50 patients with OSAHS, divided them into 23 patients with OSAHS combined with cardiovascular diseases, 27 patients with simple OSAHS and 25 normal subjects. The three groups were monitored by polysomnography. Enzyme linked immunosorbent assay (ELISA) was used to determine the levels of HIF-1α, VEGF and EPO in plasma of 22:00 at bedtime, 2:00 in the nighttime and 7:00 at next morning. It was found that the levels of plasma HIF-1α, VEGF and EPO in the patients with OSAHS combined with cardiovascular disease and simple OSAHS group were higher than that of the normal control group. In OSAHS combined cardiovascular disease group, the levels of HIF-1α and VEGF increased significantly at night and decreased in the morning, but higher than before sleep. The HIF-lα and VEGF levels were negatively correlated with the nocturnal minimum oxygen saturation. It prompted that CIH might increase the expression of VEGF and EPO via HIF-lα. EPO was involved in the pathophysiological processes such as anti-hypoxia and promoting angiogenesis. This effect was relieved by transient hypoxic damage during sleep. If VEGF continued to increase in excess, it might lead to abnormal angiogenesis and increased vascular permeability, which might be an important factor in the cardiovascular complications of OSAHS.