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This paper presents new geometric viewpoints to Chen chaotic system. Firstly, the existence of two nontransverse homoclinic orbits in Chen system is rigorously proved beyond the classical parameters. Secondly, combined with the theory of tangent bundle, a new geometric viewpoint is given to explore chaos mechanism of Chen system. The fundamental geometric definition of tangent bundle and the essential role of nonlinear connection between the tangent space and the base space are described. By introducing the geometrical viewpoints of second order system governed by Lie-Poisson equation, some geometric invariants of Chen system can be obtained. Furthermore, the torsion tensor as one of the geometric invariants is obtained, and it gives the geometrical interpretation to the chaotic behaviour of Chen system. Finally, the torsion tensor of Chen system and Lorenz system are also compared. The obtaining results show that torsion tensor change will lead the Chen system from periodic to chaotic, which is not found in Lorenz system. [ABSTRACT FROM AUTHOR]

Objectives: To analyze cognitive functions and tau-protein expression in peripheral blood lymphocytes of retired aluminum (Al)-exposed workers. Methods: A total of 66 retired Al potroom workers and 70 unexposed controls were investigated. The cognitive functions were assessed with the Mini-Mental State Examination. The tau-protein expression in peripheral blood lymphocyte was analyzed with Western blot. Results: The cognitive functions of the exposed group were significantly decreased. Twelve mild cognitive impairment cases in the exposed group and four mild cognitive impairment cases in the control group were diagnosed. Significantly higher p-tau181 and p-tau231 levels were detected in the Al-exposed workers than in the control group. Conclusions: The study suggests that long-term exposure to Al may cause cognitive disorders and that p-tau181 and p-tau231 might be useful indicators for monitoring cognitive decline in Al-exposed workers. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the serum levels of interleukin-6 (IL-6), CXC chemokine ligand-10 (CXCL-10) and intercellular adhesion molecule-l (ICAM-1) in patients with Graves' disease (GD) following iodine-131 (131I) therapy. A total of 30 patients with GD participated in the present study. Serum cytokine levels were measured with ELISA, and correlation analyses were performed. Serum levels of IL-6, CXCL-10 and ICAM-1 were significantly higher in patients with GD prior to treatment than those in the control subjects (P<0.01). Following 131I therapy, the serum levels of IL-6 and CXCL-10 in patients with GD were markedly increased within the first week, gradually decreased to the pretreatment level in the subsequent six months and decreased further at 18 months post-treatment. However, the serum levels of IL-6 and CXCL-10 in patients with GD at 18 months following 131I therapy remained significantly higher than in control subjects (P<0.01). Conversely, serum ICAM-1 levels in patients with GD were gradually increased in the 12 months following 131I therapy and reached a relatively stable level thereafter. Furthermore, the Pearson's correlation analysis indicated that the serum levels of IL-6, CXCL-10 and ICAM-1 were not associated with free triiodothyronine, the free thyroxine index, and thyroid-stimulating hormone in these patients. 131I therapy was able to alter the immune/inflammatory responses in the thyroids of patients with GD. However, these cytokines (IL-6, CXCL-10, and ICAM-1) are not associated with thyroid function; therefore, they cannot be used as prognostic markers for the 131I therapy of GD. [ABSTRACT FROM AUTHOR]

Objective: To investigate the relationship between cognitive impairment and global DNA methylation in aluminum (Al) potroom workers. Methods: A total of 366 Al-exposed workers were investigated, and their cognitive functions were assessed with the Mini-Mental State Examination (MMSE). Aluminum in serum was quantified using graphite furnace atomic absorption spectrometry. Global DNA methylation was analyzed in whole blood using an enzyme-linked immunosorbent assay--like reaction. Results: Mini-Mental State Examination scores and global DNA methylation decreased with the increase of serum Al concentration. Forty-three mild cognitive impairment (MCI) people were diagnosed. Global DNA methylation of the MCI was lower than the non-MCI. Multiple logistic analysis showed that the Al-exposed workers had lower global DNA methylation and higher serum Al concentration and were at the higher risk of MCI. Conclusions: Long-term exposure to Al may cause MCI. Mild cognitive impairment was significantly associated with global DNA methylation in blood. [ABSTRACT FROM AUTHOR]