Failure behavior of concrete subjected to high dynamic loading of new spiral projectile

A new spiral warhead structure which makes concrete failure by self-rotation is proposed in this paper. Concrete dynamic response when subjected to the oval and new proposed spiral projectile vertical and oblique-angle (from 60° to 70°) impacts of different velocities is studied numerically. This investigation obtains the specific law between different residual velocity and rotation angle when concrete target subjected to the impact loading of spiral projectile ranging from 700 m/s ~ 1000 m/s. It also shows the law between different residual velocity and the groove depth. The rotational angular velocity vs time curves for different working condition are given

Finite element analysis of gear of full-rotating propeller steering assembly

In order to ensure that the gear of the steering component of the full-rotation propeller meets the limit of bearing capacity and normal use under the action of moment load, this paper takes a steering propeller device as the research object, establishes the finite element model of the gear of the steering component under normal and braking conditions, carries out stress bending strength analysis, and carries out modal analysis. It is verified that the gear of the steering assembly meets the safety requirements, which provides a reference for the design of the steering device

Regulation of CCL5 Expression in Smooth Muscle Cells Following Arterial Injury

Chemokines play a crucial role in inflammation and in the pathophysiology of atherosclerosis by recruiting inflammatory immune cells to the endothelium. Chemokine CCL5 has been shown to be involved in atherosclerosis progression. However, little is known about how CCL5 is regulated in vascular smooth muscle cells. In this study we report that CCL5 mRNA expression was induced and peaked in aorta at day 7 and then declined after balloon artery injury, whereas IP-10 and MCP-1 mRNA expression were induced and peaked at day 3 and then rapidly declined

High-frequency stimulation of nucleus accumbens changes in dopaminergic reward circuit

Deep brain stimulation (DBS) of the nucleus accumbens (NAc) is a potential remedial therapy for drug craving and relapse, but the mechanism is poorly understood. We investigated changes in neurotransmitter levels during high frequency stimulation (HFS) of the unilateral NAc on morphine-induced rats. Sixty adult Wistar rats were randomized into five groups: the control group (administration of saline), the morphine-only group (systematic administration of morphine without electrode implantation), the morphine-sham-stimulation group (systematic administration of morphine with electrode implantation but not given stimulation), the morphine-stimulation group (systematic administration of morphine with electrode implantation and stimulation) and the saline-stimulation group (administration of saline with electrode implantation and stimulation). The stimulation electrode was stereotaxically implanted into the core of unilateral NAc and microdialysis probes were unilaterally lowered into the ipsilateral ventral tegmental area (VTA), NAc, and ventral pallidum (VP). Samples from microdialysis probes in the ipsilateral VTA, NAc, and VP were analyzed for glutamate (Glu) and caminobutyric acid (GABA) by high-performance liquid chromatography (HPLC). The levels of Glu were increased in the ipsilateral NAc and VP of morphine-only group versus control group, whereas Glu levels were not significantly changed in the ipsilateral VTA. Furthermore, the levels of GABA decreased significantly in the ipsilateral NAc, VP, and VTA of morphineonly group when compared with control group. The profiles of increased Glu and reduced GABA in morphine-induced rats suggest that the presence of increased excitatory neurotransmission in these brain regions. The concentrations of the Glu significantly decreased while the levels of GABA increased in ipsilateral VTA, NAc, and VP in the morphine-stimulation group compared with the morphine-only group. No significant changes were seen in the morphine-sham stimulation group compared with the morphine-only group. These findings indicated that unilateral NAc stimulation inhibits the morphineinduced rats associated hyperactivation of excitatory neurotransmission in the mesocorticolimbic reward circuit

N-(4-hydroxyphenyl) retinamide inhibits migration of renal carcinoma cells and promotes autophagy via MAPK p38 pathway

Purpose: To investigate the effect of N-(4-hydroxyphenyl) retinamide (4HPR) on autophagy and migration of renal carcinoma cells.Methods: Renal cancer cell lines were treated with various concentrations of 4HPR. Proliferation of the cells was studied using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltrazolium bromide (MTT), while apoptosis and cell cycle arrest were determined by flow cytometry.Results: Treatment of RCCs with 30 μM 4HPR caused significant inhibition of viability. In 786-O and OS-RC-2 cell lines, 4HPR reduced colony formation by 39 and 43 %, respectively. In addition, 4HPR increased the percentage of 786-O cells in G1 phase from 58.79 ± 3.43 to 71.68 ± 4.47 % (p < 0.05). It also decreased the percentage of cells in the S-phase from 21.98 ± 2.78 to 09.17 ± 1.43 %, and enhanced the activation of p38 and JNK in 786-O cells at 48 h. Western blot assay showed that the activation of p38 and JNK by 4HPR was inhibited on pre-treatment with SB203580 (inhibitor of p38) and SP600125 (inhibitor of JNK), respectively. Reduction of 786-O cell viability by 4HPR treatment was also significantly inhibited by pre-treatment with sp203580 and sp600125 (p < 0.05). Furthermore, the inhibitors also reversed the effect of 4HPR on the expressions of Bax and Bcl-2 in 786-O cells.Conclusion: These results indicate that 4HPR inhibits the growth of renal cancer cells via activation of MAPK signalling pathway. Thus, 4HPR is a potential drug target for management of renal cancer.Keywords: Retinamide, Renal cancer, Autophagy, MAPK signalling, Cell proliferation, N-terminal kinas

Development of a Low Motion-Noise Humanoid Neck: Statics Analysis and Experimental Validation

Abstract-This paper presents our recently developed humanoid neck system that can effectively mimic motion of human neck with very low motion noises. The feature of low motion noises allows our system to work like a real human head/neck. Thus the level of acoustic noises from wearable equipments, such as donning respirators or chemical-resistant jackets, induced by human head motion can be simulated and investigated using such a system. The objective of this investigation is to facilitate using head-worn communication devices for the person who wears the protective equipment/uniform that usually produces communication-noise when the head/neck moves. Our low motion-noise humanoid neck system is based on the spring structure, which can generate 1 Degree of Freedom (DOF) jaw movement and 3DOF neck movement. To guarantee the low-noise feature, no noise-makers like gear and electrodriven parts are embedded in the head/neck structure. Instead, the motions are driven by seven cables, and the actuators pulling the cables are sealed in a sound insulation box. Furthermore, statics analysis of the system has been processed completely. Experimental results validate the analysis, and clearly show that the head/neck system can greatly mimic the motions of human head with an A-weighted noise level of 30 dB or below

Numerical Analysis on the Joint Weakening Effect of Rock Mass Behaviors in Tension

AbstractThe presence of joints and other types of discontinuities has a significant effect on the mechanical properties of rock, especially for tensile properties to fundamentally influence the stability of rock excavations. The main challenge associated with the experimental research on jointed rock lies in the difficulty to carry out amount of direct tensile tests for analysis of the effect of joint geometric parameters on mechanical properties. In this study, a particle flow model was established by utilizing the flat-joint contact model (FJM) to represent the rock materials. After microscopic parameter calibration, 53 sets of the numerical model were used for investigating the relationship between jointed geometric parameters and tensile mechanical properties. The results show that the crack initiation is related to trace length l and joint angle β, and the tensile-shear crack will appear as β increase. The uniaxial tension strength σt and β had first a weak negative correlation and then a positive correlation as the β increases, which was consistent with mathematical calculations. Furthermore, the relative importance (RI) analysis showed that the β plays a decisive role among the joint geometric parameters for affecting σt, and the effect factors of σt were joint angle β, length l, density n, and aperture d in that order. The present research can be utilized for multiple purposes in the field of jointed rock engineering, such as prediction of surrounding rock instability analysis and estimating the variable values in the inversion analysis in practical engineering projects

Effect of cation exchange capacity of soil on stabilized soil strength

AbstractWhile a certain correlation between the cation exchange capacity (CEC) of the soil and the strength of the cement stabilized soil has been reported, the mechanism remains unclear. In this research, a set of soil samples with different CECs were stabilized with different proportions of cement and calcium hydroxide (Ca(OH)2, CH). The influence of soil CEC on the strength of the stabilized soil was investigated by analyzing the CH saturation in the pore solution and measuring the strength of the stabilized soil specimens. It is revealed that cation exchange in the soil can reduce the CH saturation of the stabilized soil. If the CEC of the soil is too high, the CH in the pore solution of the stabilized soil cannot reach the saturation level, and further cation exchange would then consume the Ca2+ ions which should be originally used to generate calcium silicate hydrate, thus result in the poor strength of the stabilized soil

Isolation and characterization of a genotype 4 Hepatitis E virus strain from an infant in China

In the present study, a genotype 4 HEV strain was identified in the fecal specimen from a seven months old infant with no symptom of hepatitis in Shanghai Children's hospital. The full capsid protein gene (ORF2) sequence of this strain was determined by RT-PCR method. Sequence analysis based on the full ORF2 sequence indicated that this HEV strain shared the highest sequence identity (97.6%) with another human HEV strain isolated from a Japanese patient who was infected by genotype 4 HEV during traveling in Shanghai. Phylogenetic analysis showed that this genotype 4 HEV was phylogenetically far from the genotype 4 HEV strain that was commonly prevalent in Shanghai swine group, suggesting that this strain may not come from swine group and not involved in zoonotic transmission in this area