ABSTRACT
We present a reduced order model for efficient nonlinear homogenization of bones, accounting for strength difference effects and containing some well-known plasticity models (like von Mises or Drucker-Prager) as special cases. The reduced order homogenization is done by using a cluster-based model order reduction technique, called cluster-based nonuniform transformation field analysis. For an offline phase, a space-time decomposition is performed on the mesoscopic plastic strain fields, while a clustering analysis is employed for a spatial decomposition of the mesoscale RVE model. A volumetric-deviatoric split is additionally introduced to capture the enriched characteristics of the mesoscopic plastic strain fields. For an online analysis, the reduced order model is formulated in a unified minimization problem, which is compatible with a large variety of material models. Both cortical and trabecular bones are considered for numerical experiments. Compared to conventional FE-based RVE computations, the developed reduced order model renders a considerable acceleration rate beyond 10 3 , while maintaining a sufficient accuracy level.
Subject(s)
Bone and Bones , Cancellous BoneABSTRACT
In this paper, the barrier mechanism of silico-alkaline sol-modified bentonite as cutoff wall materials for lead ions in leadzinc tailings ponds was investigated. Mechanical property tests, adsorption capacity tests, and permeability tests were conducted to assess the performance of the materials. The results indicated that the addition of silico-alkaline sol at a proportion of 20% by weight of bentonite improved the mechanical strength, anti-seepage ability, and adsorption capacity of the materials towards lead ions. The modification process of bentonite using silico-alkaline sol was confirmed through XED analysis. It was observed that silico-alkaline sol particles adsorbed onto the end face of montmorillonite crystal layer, altering its charge properties. This modification enhanced the adsorption capacity of bentonite towards metal cations. The interaction between the cutoff walls and lead ions was primarily governed by ion exchange. Through the utilization of CT and the finite element method (FEM), demonstrated the exiguity of connected flow lines in the vertical direction within the cutoff walls. Furthermore, column tests revealed that lead ions permeating through the cutoff walls gradually transformed into residuals and were immobilized within the wall. Visual Modflow analysis confirmed the effective application of the cutoff wall in remediating contaminated sites and the potential for practical implementation.
Subject(s)
Bentonite , Zinc , Bentonite/chemistry , Ponds , Environmental Pollution , Adsorption , Ions , Hydrogen-Ion ConcentrationABSTRACT
With the development of technology, drugs are being developed for different purposes. Thus, the rate of drug injury considerably increased worldwide. Liver is the largest detoxification organ in the human body, but it is also the organ most vulnerable to drug damage. Ginsenoside Rg1 has been reported to have an extensive protective effect on liver injury. However, no evident results showed whether ginsenoside Rh1 could improve the injury caused by drugs. Therefore, this paper aimed to explore the protective effect in a mouse model with liver injury. Mice administered with acetaminophen (APAP) were used as the negative group, while those administered with Rg1 (10, 20, and 30 mg/kg) and Rh1 (10, 20, and 30 mg/kg) were used as the prevention groups. Results indicated that the treatments increased the levels of GSH and SOD remarkably and decreased that of MDA. In addition, the expression levels of GOT and GPT was remarkably reduced compared with the negative group. Inflammatory agents TNF-α, IL-6, and IL-1ß were also decreased by the treatments. Meanwhile, Rg1 and Rh1 not only prevented the expression of Bax but also promoted Bcl-2 levels in mice. All results suggested that ginsenoside Rg1 and ginsenoside Rh1 exerted a preventive effect on APAP-induced liver injury in mice. PRACTICAL APPLICATIONS: With the increasing number of patients suffering from drug-induced liver injury, it is urgent to find alternative natural plant drugs to treat liver injury. This paper focuses on the protective effects of Ginsenoside Rg1 and ginsenoside Rh1 on acetaminophen (APAP) induced liver injury. From the previous studies, we found that there is no sufficient evidence to show that ginsenoside Rh1 has protective effect on liver injury. In this paper, the detection of oxidative stress indicators, liver histopathological analysis and immunoprotein analysis show that both ginsenoside Rg1 and ginsenoside Rh1 have preventive effect on liver injury caused by APAP, which provides a reference for the follow-up experimental research.