Numerical simulation of chloride diffusion in cementitious materials by lattice type model

The chloride ingress is one of the most significant problems to reinforced concrete structures in coastal areas and cold regions where the de-icing salt is commonly used. In this paper, the lattice type model which has been widely used in fracture analysis of brittle materials is applied to simulate the chloride diffusion process in cementitious materials. The theoretical background of the lattice type model in solving the mass transport problem is briefly presented. The analytical solution of the Fick’s law is adopted to theoretically validate the developed lattice type model. After that, two typical case studies are included to demonstrate the application of the lattice type model in the chloride ingress issue. In the first case, the tortuosity effect of the aggregates on the chloride diffusion front at meso-scale is studied by the lattice model. In the second case, the lattice model is applied in the simulation of the chloride diffusion in cracked concrete. The results show that the lattice type model can be a useful tool to simulate the chloride ingress in the cementitious materials

Transfusion of Resting Platelets Reduces Brain Hemorrhage After Intracerebral Hemorrhage and tPA-Induced Hemorrhage After Cerebral Ischemia

BackgroundExacerbated blood-brain barrier (BBB) damage is related with tissue plasminogen activator (tPA)-induced brain hemorrhage after stroke. Platelets have long been recognized as the cellular orchestrators of primary haemostasis. Recent studies have demonstrated further that platelets are required for supporting intact mature blood vessels and play a crucial role in maintaining vascular integrity during inflammation. Therefore, we sought to investigate whether platelets could reduce tPA-induced deterioration of cerebrovascular integrity and lead to less hemorrhagic transformation.MethodsMice were subjected to models of collagenase-induced intracerebral hemorrhage (ICH) and transient middle cerebral artery (MCA) occlusion. After 2 h of MCA occlusion, tPA (10 mg/kg) was administered as an intravenous bolus injection of 1 mg/kg followed by a 9 mg/kg infusion for 30 min. Immediately after tPA treatment, mice were transfused with platelets. Hemorrhagic volume, infarct size, neurological deficit, tight junction and basal membrane damages, endothelial cell apoptosis, and extravascular accumulation of circulating dextran and IgG, and Evans blue were quantified at 24 h.ResultsPlatelet transfusion resulted in a significant decrease in hematoma volume after ICH. In mice after ischemia, tPA administration increased brain hemorrhage transformation and this was reversed by resting but not activated platelets. Consistent with this, we observed that tPA-induced brain hemorrhage was dramatically exacerbated in thrombocytopenic mice. Transfusion of resting platelets ameliorated tPA-induced loss of cerebrovascular integrity and reduced extravascular accumulation of circulating serum proteins and Evans blue, associated with improved neurological functions after ischemia. No changes were found for infarct volume. Inhibition of platelet receptor glycoprotein VI (GPVI) blunted the ability of platelets to attenuate tPA-induced BBB disruption and hemorrhage after ischemia.ConclusionOur findings demonstrate the importance of platelets in safeguarding BBB integrity and suggest that transfusion of resting platelets may be useful to improve the safety of tPA thrombolysis in ischemic stroke

Integrated Network Pharmacology and Metabolomics Analysis of the Therapeutic Effects of Zi Dian Fang on Immune Thrombocytopenic Purpura

Current hormone-based treatments for immune thrombocytopenic purpura (ITP) are associated with potentially serious adverse reactions. Zi Dian Fang (ZDF) is a multi-target Traditional Chinese Medicine (TCM) used to treat both the symptoms and root causes of ITP, with fewer side effects than hormone-based treatments. This study analysis of the therapeutic effects of ZDF on ITP from three aspects: platelet proliferation, immunoregulation, and inflammation. After detection of 52 chemical constituents of ZDF by UPLC-Q-TOF/MS, The main targets and pathways affected by ZDF were screened by network pharmacology and verified by Western blot and ELISA. Meanwhile, metabolomics analysis were applied to a mouse model of ITP to identify and screen endogenous terminal metabolites differentially regulated by ZDF. Integrated network pharmacology and metabolomics analysis of the therapeutic effects of ZDF on ITP may be as follows: ZDF counteracts ITP symptoms mainly by inhibiting Ras/MAPKs (Ras/Mitogen-activated protein kinases) pathway, and the expression of upstream protein (Ras) and downstream protein (p-ERK, p-JNK, p-p38) were inhibited, which affects the content of effect index associated with proliferation (Thrombopoietin, TPO; Granulocyte-macrophage colony stimulating factor, GM-CSF), inflammation (Tumor necrosis factor-α, TNF-α; Interleukin-6, IL-6), immune (Interleukin-2, IL-2; Interferon-gamma, IFN-γ; Interleukin-4, IL-4), so that the body’s arginine, Δ12-prostaglandin j2 (Δ12-PGJ2), 9-cis-Retinoic Acid, sphingosine-1-phosphate (S1P), oleic acid amide and other 12 endogenous metabolites significantly changes. Considering the established safety profile, the present study suggests ZDF may be a useful alternative to hormone-based therapies for the treatment of ITP

Growth Differentiation Factor 11 Promotes Neurovascular Recovery After Stroke in Mice

Background: Growth differentiation factor 11 (GDF11), a member of transforming growth factor-β (TGF-β) superfamily, was shown to rejuvenate cardiac and skeletal muscle function and to improve cerebral vasculature and neurogenesis in old mice. However, recent experimental data reported that raising GDF11 levels inhibited skeletal muscle regeneration and had no effect on cardiac hypertrophy. Our aim was to investigate the effects of GDF11 on brain repair during the recovery phase after stroke.Methods: Mice were subjected to distal middle cerebral artery occlusion, and recombinant GDF11 (rGDF11) was injected intraperitoneally once a day during days 7–13 after stroke. Neuronal precursor cells (NPCs) proliferation and angiogenesis were assayed at 14 days. Neuronal regeneration was assayed at 42 days. The beam-walking test and CatWalk were used to evaluate behavioral functions. Downstream pathways of GDF11 were also investigated.Results: GDF11 was upregulated in the ipsilateral peri-infarct cortex and subventricular zone (SVZ) at 14 days after stroke. Treatment with rGDF11 enhanced the number of newborn NPCs and endothelial cells, microvascular length and area, and brain capillary perfusion. Western blots showed that rGDF11 upregulated brain-derived neurotrophic factor (BDNF) and increased the levels of proangiogenic factor angiopoietin-2 (Ang-2) and phosphorylation of vascular endothelial growth factor receptor-2 (VEGFR-2). We also found that rGDF11 upregulated the transcription factors Smad2 and Smad3 phosphorylation, but these activations were blocked by a TGF-β receptor inhibitor SB431542. Moreover, rGDF11-induced angiogenic remodeling and NPCs proliferation were reversed by injection of SB431542, suggesting that GDF11 may exert its effect via the TGF-β/Smad2/3 signaling pathway. Finally, treating mice with rGDF11 resulted in a significant increase in neuronal regeneration and functional recovery.Conclusion: GDF11 promoted neurogenesis and angiogenesis and contributed to functional recovery after stroke in mice

Challenges in microbial ecology: building predictive understanding of community function and dynamics.

The importance of microbial communities (MCs) cannot be overstated. MCs underpin the biogeochemical cycles of the earth's soil, oceans and the atmosphere, and perform ecosystem functions that impact plants, animals and humans. Yet our ability to predict and manage the function of these highly complex, dynamically changing communities is limited. Building predictive models that link MC composition to function is a key emerging challenge in microbial ecology. Here, we argue that addressing this challenge requires close coordination of experimental data collection and method development with mathematical model building. We discuss specific examples where model-experiment integration has already resulted in important insights into MC function and structure. We also highlight key research questions that still demand better integration of experiments and models. We argue that such integration is needed to achieve significant progress in our understanding of MC dynamics and function, and we make specific practical suggestions as to how this could be achieved

A study on image-processing based identification of aspect ratio of coarse aggregate

The mesoscopic simulation of behaviours of cementitious materials under different conditions has become a hot topic in academic research, as it provides more details to the mechanism study and structural design. To conduct a mesoscopic simulation, the meso-scale model of cementitious materials must be built. To ensure the precision of the aggregate shape in the simulated meso-scale model, key shape parameters of real aggregates should be identified. In this paper, an image-processing based method is proposed to detect the aspect ratio of a polygonal aggregate. The procedure and used algorithms are demonstrated in detail. As an application, totally about 1000 coarse aggregates from the Xinjiang, China are selected to identify the aspect ratio. It is found that the aspect ratio of coarse aggregates is a random variable following the Generalized Extreme Value (GEV) distribution. The published data by using the X-ray technique is also adopted as a comparison, and the results are almost the same as each other, which indicates that the aggregate source does not have an obvious effect on the probabilistic characteristics of the aspect ratio

Numerical simulation of chloride diffusion in cementitious materials by lattice type model

The chloride ingress is one of the most significant problems to reinforced concrete structures in coastal areas and cold regions where the de-icing salt is commonly used. In this paper, the lattice type model which has been widely used in fracture analysis of brittle materials is applied to simulate the chloride diffusion process in cementitious materials. The theoretical background of the lattice type model in solving the mass transport problem is briefly presented. The analytical solution of the Fick’s law is adopted to theoretically validate the developed lattice type model. After that, two typical case studies are included to demonstrate the application of the lattice type model in the chloride ingress issue. In the first case, the tortuosity effect of the aggregates on the chloride diffusion front at meso-scale is studied by the lattice model. In the second case, the lattice model is applied in the simulation of the chloride diffusion in cracked concrete. The results show that the lattice type model can be a useful tool to simulate the chloride ingress in the cementitious materials

Melatonin-Mediated Regulation of Growth and Antioxidant Capacity in Salt-Tolerant Naked Oat under Salt Stress

Melatonin (MT; N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that has been demonstrated to play an important role in plant growth, development, and regulation of environmental stress responses. Studies have been conducted on the role of the exogenous application of MT in a few species, but the potential mechanisms of MT-mediated stress tolerance under salt stress are still largely unknown. In this study, naked oat seedlings under salt stress (150 mM NaCl) were pretreated with two different concentrations of MT (50 and 100 μM), and the effects of MT on the growth and antioxidant capacity of naked oat seedlings were analyzed to explore the regulatory effect of MT on salt tolerance. The results showed that pretreating with different concentrations of MT promoted the growth of seedlings in response to 150 mM NaCl. Different concentrations of MT reduced hydrogen peroxide, superoxide anion, and malondialdehyde contents. The exogenous application of MT also increased superoxide dismutase, peroxidase, catalase, and ascorbate peroxide activities. Chlorophyll content, leaf area, leaf volume, and proline increased in the leaves of naked oat seedlings under 150 mM NaCl stress. MT upregulated the expression levels of the lipid peroxidase genes lipoxygenase and peroxygenase, a chlorophyll biosynthase gene (ChlG), the mitogen-activated protein kinase genes Asmap1 and Aspk11, and the transcription factor genes (except DREB2), NAC, WRKY1, WRKY3, and MYB in salt-exposed MT-pretreated seedlings when compared with seedlings exposed to salt stress alone. These results demonstrate an important role of MT in the relief of salt stress and, therefore, provide a reference for managing salinity in naked oat

The prevalence of hepatitis B in Chinese general population from 2018 to 2022: a systematic review and meta-analysis

Abstract Background Within China, Hepatitis B virus (HBV) infection remains widely prevalent and one of the major public health problems. There have been only two previous estimates of its prevalence at the population level in China, with the latest survey conducted in 2006. A meta-analysis estimated the prevalence of HBV within China between 2013 and 2017 as 7%. This review provides an updated estimate of HBV prevalence in China from 2018 to 2022. Methods Systematic searches of literature from January 1, 2018 to December 25, 2022 were conducted in four international databases (Medline, Web of Science, Embase, Cochrane Database of Systematic Reviews) and three Chinese databases (CNKI, CBM, and WanFang data). Random-effects meta-analyses were conducted to calculate the pooled HBV prevalence with 95% confidence intervals in the overall population and subgroups. Publication bias, heterogeneity between studies, and study quality were assessed. Results Twenty-five articles were included in the meta-analysis. The pooled prevalence of HBV infection in the Chinese general population from 2018 to 2022 was 3% (95%CI: 2–4%). The prevalence of HBV infection was similar between males and females (both 3%), while rural areas had a higher prevalence than urban areas (3% vs 2%). The highest prevalence of HBV was reported in the eastern provinces (4, 95%CI: 2–6%). The HBV prevalence of people aged ≥18 years old (6, 95%CI: 4–8%) was higher than people aged < 18 years old (0, 95%CI: 0–1%). Conclusion Compared to the previous meta-analysis prevalence in 2013–2017, the updated meta-analysis estimated prevalence of HBV infection (3%) from 2018 to 2020 showed a decreasing trend, suggesting China had moved into a lower intermediate epidemic area (2–5%). However, the prevalence of HBV in rural areas and eastern regions was still higher than the national average. People aged ≥18 years old showed a higher HBV prevalence. HBV prevention should be prioritized in the highest-prevalence areas and high-risk populations. Due to heterogeneity in data collection methods among studies, there remains a need for systematic surveillance of nationwide HBV prevalence