A Novel Real-Valued DOA Algorithm Based on Eigenvalue.

To solve the high complexity of the subspace-based direction-of-arrival (DOA) estimation algorithm, a super-resolution DOA algorithm is built in this paper. However, in this method, matrix decomposition is required for each search angle. Therefore, in this paper, real-valued processing is used to reduce the scanning range by half, which is less effective in algorithm complexity. The super-resolution algorithm mainly uses the conservation of energy. By exploring the relationship between the covariance matrix and its complex conjugate, we constructed the real-valued matrix and introduced a real-valued searching source to make the operation of the matrix real-valued. Finally, the simulation experiments show that the proposed algorithm not only reduces the spectral search range by half but also has a higher angular resolution than the traditional algorithm.

Fenugreek lactone attenuates palmitate-induced apoptosis and dysfunction in pancreatic ß-cells.

AIM: To investigate the effect of fenugreek lactone (FL) on palmitate (PA)-induced apoptosis and dysfunction in insulin secretion in pancreatic NIT-1 ß-cells. METHODS: Cells were cultured in the presence or absence of FL and PA (0.25 mmol/L) for 48 h. Then, lipid droplets in NIT-1 cells were observed by oil red O staining, and the intracellular triglyceride content was measured by colorimetric assay. The insulin content in the supernatant was determined using an insulin radio-immunoassay. Oxidative stress-associated parameters, including total superoxide dismutase, glutathione peroxidase and catalase activity and malondialdehyde levels in the suspensions were also examined. The expression of upstream regulators of oxidative stress, such as protein kinase C-α (PKC-α), phospho-PKC-α and P47phox, were determined by Western blot analysis and real-time PCR. In addition, apoptosis was evaluated in NIT-1 cells by flow cytometry assays and caspase-3 viability assays. RESULTS: Our results indicated that compared to the control group, PA induced an increase in lipid accumulation and apoptosis and a decrease in insulin secretion in NIT-1 cells. Oxidative stress in NIT-1 cells was activated after 48 h of exposure to PA. However, FL reversed the above changes. These effects were accompanied by the inhibition of PKC-α, phospho-PKC-α and P47phox expression and the activation of caspase-3. CONCLUSION: FL attenuates PA-induced apoptosis and insulin secretion dysfunction in NIT-1 pancreatic ß-cells. The mechanism for this action may be associated with improvements in levels of oxidative stress.

[Effect of sinomenine on adjuvant arthritis and its mechanisms].

OBJECTIVE: To discuss the anti-inflammatory mechanism of sinomenine on inflammatory media in joint of adjuvant arthritis rats. METHOD: Rats were randomly divided into the normal group and the model group, the prednisone group, the small, medium, large of sinomenine group (30, 60, 120 mg x kg(-1)). Except for the rats in the normal group, animals were modeled to adjuvant arthritiswith freund's complete adjuvant. The arthritis index (AI) and the swelling degree of paws were recorded, and the activity of IL-1, TNF and the levels of NO, PGE2 in joint fluids of secondary arthritis were determined. RESULT: Compared with the normal group, the activity of IL-1, TNF and the levels of NO, PGE2 in joint fluids of secondary arthritis were increased significantly in the model group (P < 0.05). Compared with the model group, it was shown to exert a dramatic inhibitory effect on secondary reaction of freund's adjuvant arthritis of rats, and the activity of IL-1, TNF and the levels of NO, PGE2 in joint fluids of secondary arthritis were significantly decreased in the sinomenine group (P < 0.05). CONCLUSION: Sinomenine has a remarkable treatment effect on RA. It is via NO to inhibit the activity of cytokines and decrease the level of inflammation mediators, which may be one of its curing RA mechanism.

[Expression of brain-derived neurotrophic factor in hippocampus of ovariectomized mouse].

OBJECTIVE: To explore the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus after ovariectomy in mice. METHODS: BDNF levels were detected by immunohistochemistry combined image analysis in hippocampal CA regions and dentate gyrus of ovariectomized mice. RESULTS: The expression of BDNF in hippocampus of mice decreased significantly after the ovariectomy after 4 days. The recovery BDNF expression started 14 days after the ovariectomy and after 28 days, the expression of BDNF in hippocampus recovered to the normal level. CONCLUSION: The decrease of estrogen in ovariectomized mice can weaken the expression of BDNF in hippocampus during the early stage.

[Stress and hippocampus].

This review summarizes the present advance of effects of stress on hippocampal structure and function and the role of hippocampus in feedback regulation of thalamic-pituitary-adrenocortical (HPA) axis during stress. It shows that stress can affect hippocampal structure and function, on the other hand, the hippocampus can also suppress the stress reaction through the feedback regulation of HPA axis, but chronic stress can attenuate this regulation, then significantly impair its structure and function.