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As the environment deteriorates, the frequency of fog-haze weather is getting higher and higher, which greatly affects the normal life of the people and the normal operation of highspeed railway external insulation equipment. The fog-haze is a combination of fog and haze. The haze in the air will affect pollution accumulation of the roof insulator, and the fog in the air which settles on the surface of the roof insulator will make the pollution on the surface of the roof insulator humid. This kind of humid contamination greatly increases the probability of the roof insulator's flashover. The roof insulator, as an important external insulation device for electrified railways, will cause a serious impact on the stable operation of high-speed trains in the event of failure. However, there are few studies on the contamination situation under the fog-haze and airflow environment of the roof insulator. In this paper, the FQJG2-30/16 roof insulator is used as the test object, and the force of the fog-haze particles on the surface of the insulator under the highspeed air smog environment is analyzed. It is believed that the force of the fog-haze particles mainly includes gravity, airflow drag, collision force between particles and friction between the particles and the surface of the insulator, as the same time the water film formed by the water droplets in the haze environment causes the fog-haze particles to settle on the insulator. The adhesion of the surface is increased, leading to more serious surface area contamination of the roof insulator. Based on this, a simulation model of fog-haze particles deposition on the surface of insulators in a high-speed airflow for-haze environment was established. the artificial fog-haze environment was simulated under different airflow speeds by through the artificial climate chamber to study the contamination of the roof insulator. In this paper, (NH 4 ) 2 SO 4 was used to simulate the soluble salt in the haze, and the insoluble matter was simulated by diatomaceous earth. The (NH 4 ) 2 SO 4 : diatomaceous earth = 1:6 configuration haze, 0.5 g salt, 3 g ash was selected. The water mist generated by the ultrasonic water mist generator simulates the fog in the fog-haze environment, and the influence of the haze environment on the roof insulator contamination at different airflow speeds is revealed by artificially simulating the airflow haze environment roof insulator contamination test. The simulation and test results show that in the fog-haze environment, there is a difference in surface area contamination of the roof insulator under different airflow speeds. When the air velocity is less than 30m/s, the water droplets are more likely to form a water film on the surface of the roof insulator, so that the fog-haze particles are more likely to adhere to the surface of the insulator, and the insulator surface contamination is continuously reduced as the airflow speed increases, when the airflow speed is greater than 30m/s, the highspeed airflow takes away a large number of water droplets, and the surface of the roof insulator is not easy to form a water film. At this time, the effect of the water droplet adhesion force is reduced, the airflow drag force is greater than the water droplet adhesion force, and the fog-haze particles are more prone to slip on the surface of the insulator. When the airflow speed reaches 80m/s, there is almost no fog-haze particle deposition on the roof insulator surface. Therefore, the research work in this paper can provide theoretical support for the safe and stable operation of high-speed train roof insulators.

We synthesized polyamidoamine (PAMAM) dendrimers and citrate-capped gold nanoparticles (AuNPs), and explored the applicability of the PAMAM/AuNP assay in determining total free fatty acid (FFA) contents in edible oils based on a competitive colorimetry, in which the PAMAM-triggered AuNP aggregation was suppressed by FFAs. The generation and concentration of PAMAMs, the chain lengths of FFAs as well as the concentration and pH of the background electrolytes of the assay were optimized. The average acid values of the sunflower seed, corn and extra virgin olive oils determined by PAMAM/AuNP assay were 1.31 ± 0.07, 0.33 ± 0.02 and 1.49 ± 0.07, respectively, which were not significantly different from the corresponding 1.27 ± 0.08, 0.32 ± 0.01 and 1.61 ± 0.06 by the standard nonaqueous titration. Our results suggest that the method is promising in detecting FFAs in edible oils, and implementation of the method expands the technological scope for FFA analysis.

Background: Modern pharmacological studies have confirmed that the total extract of Zhigancao Decoction, either as a single active compound or in combination, can inhibit arrhythmia. In this study, the myocardial tissue/silicon substrate microelectrode array (MEA) was used to detect the Zhigancao Decoction medicated serum of the New Zealand white rabbits right atrial appendage after rapid right atrium pacing (RAP). Methods: New Zealand white rabbits were randomly divided into four groups, with eight rabbits per group. The first group was the control animal group (Group A). The second was the drug-free serum vehicle control group (Group B). The third group used serum-containing f Zhigancao Decoction (Group C) at various concentrations. The fourth group was the Zhigancao Decoction medicated serum group (Group D). After establishing the atrial fibrillation model, the field action potential duration (fAPD) of the right atrial appendage (RAA) in the control group, and in groups after different interventions, were measured. Results: We report of an atrial fibrillation model using by rapid right atrium atrial pacing, in which fAPD was significantly shorter 12 hours after pacing (P < 0.05). The intervention by 10% to 25% of drug-containing serum or decoction could prolong the fAPD of rabbit atrial appendage in atrial fibrillation rabbits in a dose dependent manner (P < 0.05). Conclusion: fAPD can be used as an indicator for the change of cardiac electrophysiological properties. 10% to 25% of Zhigancao Decoction medicated serum can prolong fAPD in atrial fibrillation rabbits, which may be the electrophysiological mechanism of atrial fibrillation resistance.

Background: Atrial fibrillation (AF) arises from abnormalities in atrial structure and electrical activity. Microelectrode arrays (MEA) is a real-time, nondestructive measurement of the resting and action potential signal, from myocardial cells, to the peripheral circuit of electrophysiological activity. This study examined the field action potential duration (fAPD) of the right atrial appendage (RAA) by MEA in rapid atrial pacing (RAP) in the right atrium of rabbits. In addition, this study also investigated the effect of potassium ion channel blockers on fAPD. Methods: 40 New Zealand white rabbits of either sex were randomly divided into 3 groups: 1) the control, 2) potassium ion channel blocker (TEA, 4-Ap and BaCl2), and 3) amiodarone groups. The hearts were quickly removed and right atrial appendage sectioned (slice thickness 500 μm). Each slice was perfused with Tyrode’s solution and continuously stimulated for 30 minutes. Sections from the control group were superfused with Tyrode’s solution for 10 minutes, while the blocker groups and amiodarone were both treated with their respective compounds for 10 minutes each. The fAPD of RAA and action field action potential morphology were measured using MEA. Results: In non-pace (control) groups, fAPD was 188.33 ± 18.29 ms after Tyrode’s solution superfusion, and 173.91 ± 6.83 ms after RAP. In pace/potassium ion channel groups, TEA and BaCl2 superfusion prolonged atrial field action potential (fAPD) (control vs blocker: 176.67 ± 8.66 ms vs 196.11 ± 10.76 ms, 182.22 ± 12.87 ms vs 191.11 ± 13.09 ms with TEA and BaCl2 superfusion, respectively, P < 0.05). 4-AP superfusion significantly prolonged FAPD. In pace/amiodarone groups, 4-Ap superfusion extended fAPD. Conclusions: MEA was a sensitive and stable reporter for the measurement of the tissue action potential in animal heart slices. After superfusing potassium ion channel blockers, fAPD was prolonged. These results suggest that Ito, IKur and IK1 remodel and mediate RAP-induced atrial electrical remodeling. Amiodarone alter potassium ion channel activity (Ito, IKur, IK1 and IKs), shortening fAPD.

A theoretical and experimental study of density wave oscillation (DWO) in natural circulation is presented in this paper. Experiments were performed on a natural circulation test facility. The influences of mass flow rate, pressure, inlet subcooling, heat flux and exit quality on DWO were analyzed. The marginal stability boundary (MSB) of DWO was obtained. A criterion of two-phase natural circulation, which predicts the stability thresholds, was developed by lumped parameter method. It is a function of non-dimensional parameters, such as phase change number Npch, subcooling number Nsub, Froude number, Fr, geometry number Nl and friction number τ. The geometry number and friction number are first defined in this paper. A correlation of DWO period was also obtained, it is also a function of the above non-dimensional parameters. The results of the present criterion and period correlation were compared with those of the experimental data and references. It is shown that they agree very well.

Background: Acute myocardial infarction (AMI) was a type of disease with high mortality rate and high disability rate. And about 50% of the final area of myocardial infarction after AMI was led by ischemia/reperfusion (I/R) injury. The I/R injury was a kind of systemic inflammatory response, in which the main performance laid in the release of the large quantity of inflammatory cytokines. The basic experiments, clinical studies and the large scaled epidemiology investigations found that the low functions of vagus nerves had close relevance with the occurrence, development and prognosis of the cardiovascular diseases. This study investigate the effects of cholinergic anti-inflammatory pathway with with vagus never stimulation I/R injury in canine. Methods: 18 adult mongrel dogs were randomly divided into 3 groups (n = 6): sham operation group (sham Group), ischemia/reperfusion group (I/R group), right vagus nerve stimulation and ischemia/reperfusion group (STM group). The hemodynamic indexes were measured after reperfusion 120 min. Through internal jugular venous blood, serum acetylcholine (Ach), tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) concentrations were detected by ELISA. Alpha 7 subunit Ach acetylcholine receptor (α7nAchR) expression level was detected with immunohistochemical method. HE staining was used to observe the degree of neutrophil infiltration. Results: After ischemia/reperfusion 120 min, compared with sham group, TNF-α and IL-6 were significantly decreased, Ach content increased, the expression of α7nAchR protein was significantly reduced in I/R group (P < 0.05). Expression of α7nAchR protein, Ach content, TNF-α and IL-6 level had no significant difference in STM group (P < 0.05). Compared with I/R group, the expression of Ach and α7nAchR protein significantly increased the TNF- and IL-6 levels decreased in STM group (P < 0.05). Compared with the baseline, TNF-α and IL-6 levels significantly increased Ach content decreased in I/R group after ischemia /reperfusion 120 min (P < 0.05). Ach, TNF-α and IL-6 levels had no significant change in sham group and STM group of (P < 0.05). TNF-α and IL-6 were negatively correlated with Ach in I/R group (P < 0.05), and TNF-α, IL-6 were negatively correlated with Ach in group STM (P < 0.05). Massive infiltration of neutrophils were detected in myocardial tissue of I/R group, and a small number of neutrophils infiltration were detected in STM group. Conclusion: Right vagus nerve stimulation could activate anti-inflammatory pathway and inhibit the systemic and local inflammatory reaction to relieve myocardial I/R injury.