Search Results

1 - 10 of 17 items

  • Author: Qin Liu x
Clear All Modify Search
Chaotic States Induced By Resetting Process In Izhikevich Neuron Model

Abstract

Several hybrid neuron models, which combine continuous spike-generation mechanisms and discontinuous resetting process after spiking, have been proposed as a simple transition scheme for membrane potential between spike and hyperpolarization. As one of the hybrid spiking neuron models, Izhikevich neuron model can reproduce major spike patterns observed in the cerebral cortex only by tuning a few parameters and also exhibit chaotic states in specific conditions. However, there are a few studies concerning the chaotic states over a large range of parameters due to the difficulty of dealing with the state dependent jump on the resetting process in this model. In this study, we examine the dependence of the system behavior on the resetting parameters by using Lyapunov exponent with saltation matrix and Poincaré section methods, and classify the routes to chaos.

Open access
Research of User Credit Rating Analysis Technology based on CART Algorithm
Open access
Structure and tensile properties of polypropylene/carbon nanotubes composites prepared by melt extrusion

Abstract

Polypropylene/carbon nanotubes (PP/CNTs) nancomposites were prepared with a single screw extruder by adding maleic anhydride-grafted poplypropylene (PP-g-MAH) as compatibilizer to polypropylene (PP) with different amounts of carbon nanotubes (CNTs) in the range of 0.1–0.7 wt.%. Structure and morphology of the prepared samples were examined by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), polarizing light microscopy (PLM) and X-ray diffraction (XRD). The results showed that PP spherulites decreased in size when CNTs were introduced into the polymer. Mechanical properties of the samples were also studied. Tensile tests showed that with increasing amount of CNTs the strain at break decreased whereas the Young’s modulus was improved of 16.41 % to 36.05 % and tensile strength of 36.67 % to 64.70 % compared to pristine PP. The SEM microphotographs showed that majority of the CNTs were dispersed individually and oriented along the shear flow direction.

Open access
Radix Glehniae extract inhibits migration and invasion of lung cancer cells

Abstract

Objective

The aim of this study was to investigate the effect of Radix Glehniae on the migration and invasion abilities of lung cancer cells.

Methods

Normal bronchial cell line 16HBE and lung cancer cell line SK-MES-1 were treated with Radix Glehniae extract. Proliferation, migration, and invasion abilities were determined by Cell Counting Kit (CCK)-8, Transwell, and Matrigel assays, respectively. The expression and secretion levels of tissue inhibitor of metalloproteinases 2 were detected by quantitative PCR and enzyme-linked immunosorbent assay, respectively.

Results

Radix Glehniae extract inhibited the migration and invasion abilities of SK-MES-1 cells and enhanced TIMP2 expression and secretion by SK-MES-1 cells, without causing toxicity to 16HBE cells.

Conclusion

Radix Glehniae is useful in lung cancer treatment.

Open access
Electro-acupuncture on Nei Guan and Bai Hui: How Does It Affect GRP78 and Caspase-12 Gene Expression in Rats with Ischemia-Reperfusion Injury

Abstract

Objective: To observe the effects of electro-acupuncture (EA) on GRP78 and Caspase-12 gene expression in rats with ischemia- reperfusion injury (IRI) by stimulation on Nei Guan (PC6) and Bai Hui (GV20) points, so that to understand whether or not the protective effects of acupuncture is related to endocytoplasmic reticulum (ER) stressapoptosis passage.

Methods: 50 rats were randomly assigned to five groups (10 in each group): normal control(A), pseudo-operation(B), operation(C), Edaravone(D) and EA(E). The ischemia/reperfusion model of middle cerebral artery occlusion (MCAO) was established by suture embolic method. TUNEL staining method was employed to measure the apoptosis index of nerve cells in rats. Real-time polymerase chain reaction (RT-PCR) was employed to measure the mRNA expression of GRP78 and Caspase-12.

Results: Compared with normal group and pseudo-operation group, the apoptosis indexes and mRNA expression of GRP78 and Caspase-12 in operation group, Edaravone group and EA group were increased, with statistical significance(P<0.05 or P<0.01); compared with operation group, the apoptosis indexes and Caspase-12 mRNA expression in Edaravone group and EA group were decreased(P<0.05 or P<0.01), but GRP78 mRNA expression were increased(P<0.01); there were no significant difference between Edaravone group and EA group on the above indexes(P>0.05).

Conclusion: Acupuncture on Nei Guan and Bai Hui points could effectively suppress the nerve cell apoptosis in cerebral ischemia. The underlying mechanism might be related to upregulation of the ERS-protective GRP78 expression and downregulation of apoptosis-promotion Caspase-12 expression.

Open access
An Improved Feature Extraction Method for Rolling Bearing Fault Diagnosis Based on MEMD and PE

Abstract

The health condition of rolling bearing can directly influence to the efficiency and lifecycle of rotating machinery, thus monitoring and diagnosing the faults of rolling bearing is of great importance. Unfortunately, vibration signals of rolling bearing are usually overwhelmed by external noise, so the fault frequencies of rolling bearing cannot be readily obtained. In this paper, an improved feature extraction method called IMFs_PE, which combines the multivariate empirical mode decomposition with the permutation entropy, is proposed to extract fault frequencies from the noisy bearing vibration signals. First, the raw bearing vibration signals are filtered by an optimal band-pass filter determined by SK to remove the irrelative noise which is not in the same frequency band of fault frequencies. Then the filtered signals are processed by the IMFs_PE to get rid of the relative noise which is in the same frequency band of fault frequencies. Finally, a frequency domain condition indicator FFR(Fault Frequency Ratio), which measures the magnitude of fault frequencies in frequency domain, is calculated to compare the effectiveness of the feature extraction methods. The feature extraction method proposed in this paper has advantages of removing both irrelative noise and relative noise over other feature extraction methods. The effectiveness of the proposed method is validated by simulated and experimental bearing signals. And the results are shown that the proposed method outperforms other state of the art algorithms with regards to fault feature extraction of rolling bearing.

Open access
The Association Between Novel Polymorphisms of Gremlin Genes and Egg-Laying Performance Traits in Chinese Village Dagu Hens

Abstract

Gremlin (GREM1, GREM2) genes are the known bone morphogenetic proteins (BMPs) inhibitors, but their genetic diversity in animal species remains unknown. The current study was conducted to investigate single nucleotide polymorphisms (SNPs) in chicken GREM1 and GREM2 genes, and their association with egg production traits using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and deoxyribonucleic acid (DNA) sequencing. The results discovered novel SNPs and, among these variations, C/T transition at position 436 in exon 1 of the GREM1 gene leads to synonymous substitution of amino acids, and T/C transition at position 690 in the coding region of the GREM2 gene leads to a non-synonymous substitution of amino acids (valine acid 114-to-alanine acid). Association analysis established that at the age of 43, 57 and 66 wks, hen-house egg production (HHEP) was more highly significantly associated (P<0.05) with the AA genotype in the GREM1 gene. In the GREM2 gene, the TC genotype was remarkably linked with higher HHEP at the age of 30, 57 and 66 wks. Our results provide evidence that the GREM1 and GREM2 genes have potential effects on HHEP in chickens. SNPs determined in this work may be utilised as favourable potential DNA markers for improving of egg-laying performance traits.

Open access
Preparation and Characterization of a Novel Aqueous Dispersion for Enteric Coating of Pantoprazole Sodium Pellets

Abstract

The purpose of this work was to investigate a novel aqueous dispersion (Eudragit® L100-55) f or e nteric c oating o f drugs. Three different casting solutions, Eudragit® L100-55 aqueous dispersion, Eudragit® L 100-55 o rganic s olution, and Eudragit® L30D-55 aqueous dispersion, were used to prepare free films by the casting method. Drug-loaded pellets, prepared by the extrusion-spheronization method, were coated with one of these three coating solutions using the fluidized-bed spray coating technology. Properties of the free films were thoroughly investigated. Films formed by Eudragit® L100-55 aqueous dispersions showed similar properties to those formed by Eudragit® L100-55 organic solution regarding thermodynamic properties, moisture permeability, solubility and acid tolerance ability. Furthermore, the performance of the novel film was better than that formed by Eudragit® L30D-55 aqueous dispersion. Among the three enteric coating solutions, Eudragit® L100- 55 aqueous dispersion will be a promising aqueous dispersion for enteric coating and can be used in the development of enteric-coated preparations.

Open access
Dietary Fiber Extraction from Defatted Corn Hull by Hot-Compressed Water

Abstract

Corn hulls were abundant and inexpensive byproducts of the corn dry or wet milling processes, but most of them were discarded as agro-wastes. The aim of this study was to extract the dietary fiber by hot-compressed water (HCW) from defatted corn hull and to determine the chemical properties. Results showed that temperature and time played critical roles in extraction efficiency; the maximal yield of dietary fiber A (DFA) extracted by HCW reached 33.0% at 150°C for 60 min. The yield of dietary fiber B (DFB) increased from 2.0% to 56.9% as the temperature increased from 110 to 180°C, while the yield of solid residue (SR) decreased from 88.7% to 27.7%. Fourier transform infrared spectroscopy (FT-IR) results demonstrated that C-H, O-H, C=O, COO- occurred in the DFA, SR and DFB. The dietary fiber polysaccharides consisted of arabinose, galactose, glucose, xylose and uronic acid.

Open access