Porous concrete is an energy absorption material, which has been widely used in civil engineering, traffic engineering and disaster reduction engineering. However, the effect of pore structure on the impact behavior of the porous concrete is lacked. In this study, a series of drop-weight impact tests were carried out on three typical types of porous concrete, i.e., concrete hollow brick (CHB), autoclaved aerated concrete (AAC) and foamed concrete (FC), to investigate the effect of pore structures on their impact behavior. For comparison, static load tests were also conducted as references. According to the damage to the samples, the developments of impact force, strain, contact stress–strain relationship and absorbed energy during drop-weight during the impact test were measured and analyzed. The results show that the ratio between the peak impact stress and compressive strength of CHB was 0.44, while that of AAC and FC increased to about 0.6, indicating that the small and uniform pore structure in AAC and FC had a higher resistance against impact load than the hollow cavity of CHB. In addition, the elastic recovery strain in AAC increased by about 0.2% and its strain at peak contact stress increased by about 160% for a comparison of CHB, implying that a small open pore structure could enhance ductility. Besides, the peak contact stress of FC was close to that of AAC during impact loading, while the strain at peak contact stress of FC increased by about 36% compared with AAC, revealing that the closed-pore structure could further enhance the deformation potential. Correspondingly, the energy absorption rates of CHB, AAC and FC were 85.9 kJ/s, 54.4 kJ/s and 49.7 kJ/s, respectively, where AAC decreased by about 58% compared with CHB, and FC decreased by about 10% compared with AAC.
Negative skin friction (NSF) of piles in recent filling or soft area is an important effect factor of pile bearing capacity. Since field experiments on NSF are time consuming and it is difficult to large surcharge loads in experimental research, a unified calculation method of pile positive/negative skin friction was established based on the effective stress method for investigation. The closed-form analytical solutions for calculating the pile skin friction corresponding to the plastic and elastic state were derived respectively. Meanwhile, the axial load of a single pile under different distribution forms of the pile skin friction was deduced. The calculation method was verified by comparing with an in-situ test. Furthermore, a computer model, which was established by the finite element method, was used to study the effect of the friction coefficient, consolidation time, consolidation pressure, drainage condition, and pressure ratio on the distribution of NSF and the location of neutral point. The results show that the effect of the friction coefficient, consolidation time, and pressure ratio on the NSF were significant. The friction coefficient increased from 0.05 to 0.4, the position of the neutral point rose by 22%, and the drag load of pile shaft was obviously increased. The effect of consolidation pressure and drainage conditions on the neutral point were relatively less, but they had a great influence on the distribution and magnitude of NSF. Furthermore, under different consolidation pressures, the normalized maximum axial load, Fmax/p, of the pile shaft had a good linear relationship with the pressure ratio, n, and the slopes were the same.
Objective: To explore the active ingredients of ECT and their targets of asthma and investigate the potential mechanism of ECT on asthma. Methods: Firstly, the active ingredients and target of ECT were screened for BATMAN and TCMSP, functional analysis was finished via DAVID. Then, animal model was induced by ovalbumin (OVA) and aluminum hydroxide. Eosinophil (EOS) counts, EOS active substance Eosinophilic cationic protein (ECP) and eotaxin levels were detected followed the instruction. Pathological changes of lungs tissue were examined by H&E staining and transmission electron microscopy. Interleukin (IL-4, IL-10, IL-13, TNF-α), TIgE and IgE level in bronchoalveolar lavage fluid (BALF) were measured by ELISA. Finally, the protein expression of TGF-β / STAT3 pathway to lung tissue was detected by Western Blot. Results: A total of 450 compounds and 526 target genes were retrieved in Erchen tang. Functional analysis indicated that its treatment of asthma was associated with inflammatory factor and fibrosis. In the animal experiment, the results showed that ECT significantly regulated inflammatory cytokine (IL-4, IL-10, IL-13, TNF-α) levels in (P<0.05, P<0.01) , reduced EOS number (P<0.05) and also ECP and Eotaxin levels in blood (P<0.05) in BALF and / or plasma. Bronchial tissue injury was obviously improved on ECT treatment. Associated protein in TGF-β / STAT3 pathway were significantly regulated by ECT (P<0.05). Conclusion: This study originally provided the evidence that the Erchen tang was effective against the treatment of asthma symptoms, and its underlying mechanism might be regulation of inflammatory factor secretion and TGF-β/STAT3 signaling pathway.
Objective: The aim of this study is to explore the active ingredients of ECT and their targets for asthma and investigate the potential mechanism of ECT on asthma. Methods: Firstly, the active ingredients and target of ECT were screened for BATMAN and TCMSP, and functional analysis was done via DAVID. Then, the animal model was induced by ovalbumin (OVA) and aluminum hydroxide. Eosinophil (EOS) counts, EOS active substance Eosinophilic cationic protein (ECP) and eotaxin levels were detected following the instruction. Pathological changes in lung tissue were examined by H&E staining and transmission electron microscopy. Interleukin (IL-4, IL-10, IL-13, TNF-α), TIgE and IgE levels in bronchoalveolar lavage fluid (BALF) were measured by ELISA. Finally, the protein expression of the TGF-β / STAT3 pathway to lung tissue was detected by Western Blot. Results: A total of 450 compounds and 526 target genes were retrieved in Er Chen Tang. Functional analysis indicated that its treatment of asthma was associated with inflammatory factors and fibrosis. In the animal experiment, the results showed that ECT significantly regulated inflammatory cytokine (IL-4, IL-10, IL-13, TNF-α) levels in (P<0.05, P<0.01, reduced EOS number (P<0.05) and also ECP and Eotaxin levels in the blood (P<0.05) in BALF and/or plasma. Bronchial tissue injury was obviously improved on ECT treatment. Associated proteins in TGF-β / STAT3 pathway were significantly regulated by ECT (P<0.05). Conclusion: This study originally provided evidence that the Er Chen Tang was effective in the treatment of asthma symptoms, and its underlying mechanism might be the regulation of inflammatory factor secretion and the TGF-β/STAT3 signaling pathway.
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