Changes in gut motility and visceral hypersensitivity are two major features of irritable bowel syndrome (IBS). Current drug treatments are often poorly efficacious, with many side effects for patients with IBS. Complementary therapies, such as acupuncture or abdominal massage, have received more attention in recent years. In this study, a rat model of IBS with diarrhea (IBS-D) was established by instillation of acetic acid from the colon. The effects of abdominal massage on changes in gut motility, visceral hypersensitivity, and the possible mechanism were investigated. Continuous abdominal massage could decrease the stool consistency score and increase the efflux time of glass beads compared with model groups, while also decreasing mast cell counts in IBS-D rats. The mRNA and protein expressions of neuronal nitric oxide synthase (nNOS), choline acetyl transferase (CHAT), and protein gene product 9.5 (PGP9.5) were significantly upregulated by continuous abdominal massage compared with model groups. Continuous abdominal massage also improved the ultrastructure of enteric glial cells (EGCs) by decreasing the number of mitochondria and increasing the level of the heterochromatin. Meanwhile, continuous abdominal massage could upregulate the expression of glial cell line-derived neurotrophic factor (GDNF) and P-Akt/Akt. Furthermore, it could reduce visceral hypersensitivity and improve the IBS-D symptoms by regulating the phosphoinositide 3-kinase (PI3K)-Akt pathway, which would provide a novel method for the treatment of IBS-D in the clinical setting.
The precipitates, mechanical properties and strengthening effect of Cu-Ni-Si,Cu-Ni-Si-Co0.8 and Cu-Ni-Si-Co1.9 alloys are investigated. It is concluded from the TEM and XRD analysis that the strengthening of Cu-Ni-Si-Co alloy is mainly attributed to precipitates of both Ni2Si and Co2Si phases, with the same structures and very close lattice parameters. The addition of 1.9 wt% Co barely affects the precipitation process of Ni2Si or Co2Si, and may not be beneficial for enhancing the strength. The strengthening of Cu-Ni-Si-Co alloy is determined by the Orowan mechanism, and a critical precipitate radii rc about 1.5 nm corresponding to the peak strength is obtained through the theoretical analysis. It can be deduced that the peak strength of aged Cu-Ni-Si-Co alloy is obtained with the microstructures containing metastable phase and Ni2Si (or Co2Si) precipitates.
A comparative study on the friction and wear properties of three kinds of copper alloys, including Cu-Ni based, Cu-Al and Cu-Be alloys was carried out in this study. The friction pair was stainless steel, and both dry and MoS2 lubrication friction experiments were investigated. During the experiments, different loads were chosen for different alloys. It was found that under dry friction condition, the friction coefficients of both Cu-Ni based and Cu-Al alloys did not change as the loads changes, whereas the friction coefficient of Cu-Be alloy increased as the loads increases. Under lubrication friction condition, the friction coefficients of all three alloys did not change as the load changes. The results show that the dry friction coefficient of Cu-Ni based alloy was the largest (0.74), the Cu-Al alloy next (0.60), and the Cu-Be alloy had the smallest dry friction coefficient (0.54). The lubrication friction coefficient of Cu-Ni based and Cu-Be was equal and relatively smaller (0.12), whereas the Cu-Al alloy had a relative larger lubrication friction coefficient (0.27). The microstructure observations were consistent with the friction and wear performance, and the SEM results show that different wear mechanisms were dominated for different alloys.
In this paper, the flow stresses, the constitutive equation, processing map and the critical conditions of dynamic recrystallization (DRX) of the hot forged QCr0.8 alloy are studied by hot compressive test in the 750-900°C temperature and 0.01-10s-1 strain rate ranges using Gleeble-1500D thermo-mechanical simulator. The compression reduction of thermal compression deformation is 50%. The results show that the thermal deformation temperatures and strain rates have a significant effect on the high temperature deformation behavior of the alloy. The higher the temperature, the smaller the strain rate and the easier the DRX of the alloy is found.The peak stresses of the alloy decreases with the increase of temperature and increases with the increase of the strain rates.The flow stresses during hot deformation can be described by a hyperbolic sine function. The activation energy Q of the thermal compression deformation is determined to be 370.8KJ/mol. The constitutive equation and processing map of the alloy are established. Critical strains of DRX εc are studied by the inflection point characteristic of the lnθ-ε curve of the alloy and the corresponding minimum value of the ∂θ (∂θ)/∂ε-ε curve.
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