Numerical analysis of hard rock tunnel excavated by double shield TBM based on CWFS model

In order to study the mechanical response of a hard rock tunnel excavated by double shield tunnel boring machine (DS-TBM), a numerical method was introduced to simulate the TBM excavating process. The failure modes of surrounding rock mass described based on the cohesion weakening and frictional strengthening (CWFS) Mohr-Coulomb strain-softening criterion. The characteristics of stress field and plastic zone on the cross and longitudinal section of the tunnel were analyzed in detail, and the results were compared with those in the intrinsic condition (when TBM model is not activated). The simulation results indicate that the stress paths at the vault are relatively simple, and the stress concentration caused by excavation unloading is obviously reduced by lining and backfill grouting, while the sidewall is less disturbed by the excavation of TBM. The invert experiences three unloading processes, due to excavation, the contact between the rear shield and the bottom of surrounding rock, as well as backfill grouting at gap between the lining and the rock mass. The vault has a larger plastic zone than the invert, attributing to the geometrical difference between the cutter-head and the front shield, as well as the conicity of the front and rear shields. The area of plastic zones gradually increases along the tunnel route, but it becomes stable after the rear shield

Tourism Flows Prediction based on an Improved Grey GM(1,1) Model

AbstractThis study analyzes the factors affecting the tourist flow. These factors include tourism resources, traffic conditions and so on. In recent years, the grey forecasting model has achieved good prediction accuracy with limited data and has been widely used in various research fields. However, the grey forecasting model still have some potential problems that need to be improved, such as applicate range and prediction accuracy. It is found that original data and background value are main factors affecting the accuracy of the proposed model's application. To solve these problems, this study develops a optimization model for the GM(1,1) model problem which includes optimization of initial and background values. In order to reduce errors caused by back-ground values, the “new information prior using” principle is followed, and a liner function is dopted in the construe of background. Numerical examples verified that the simulation and prediction accuracy of the short-term forcasts is significantly increased. As a result, the newly improved model yields a high prediction capability

OCT1-Mediated Metformin Uptake Regulates Pancreatic Stellate Cell Activity

Background/Aims: Metformin treatment is reported to be associated with a lower incidence of and mortality from pancreatic cancer (PC) in type 2 diabetes patients. Activated pancreatic stellate cells (PSCs) are key stroma cells responsible for pancreatic fibrogenesis and PC progression. However, little research is about the influence of metformin on PSCs. Given the potential beneficial effects of metformin on PC, pancreatic tumour stroma is an important target for new therapeutics. We observed the effects of metformin on PSCs. We investigated the effects of metformin on human PSCs proliferation and the production of extracellular matrix (ECM) proteins. Methods: Cells were cultured with different concentrations of metformin (0-10 mmol/L). Cell proliferation was determined by immunofluorescence staining for nuclear Ki67 labelling. ECM production was studied by quantitative real-time polymerase chain reaction, immunoblotting and immunofluorescence microscopy. Adenosine monophosphate–activated protein kinase (AMPK), an important regulatory molecule responsible for metformin action, and the organic cation transporter member 1 (OCT1), which is believed to be the most important transporter for the pharmacological action of metformin, were investigated for their possible involvements in metformin-induced proliferation and ECM production. Results: Our results showed that metformin inhibited PSCs proliferation and decreased the production of ECM proteins by activation of AMPK phosphorylation. Silencing of OCT1 expression resulted in a reduction in the effects of metformin on PSCs activity. Conclusions: Collectively, the data indicate that OCT1 may contribute to uptake metformin and regulate PSCs activity. OCT1 is a target of metformin in regulating PSCs activity

Association of renin–angiotensin system inhibitors use with short- and long-term mortality in patients with aortic stenosis: A systematic review and meta-analysis

PurposeThe present study aimed to investigate the association of renin–angiotensin system inhibitors (RASi) with short- and long-term mortality in patients with aortic stenosis (AS).MethodsA systematic search was performed in PubMed, Embase, and Cochrane library databases for relevant studies published before March 2022. Studies meeting the inclusion criteria were included to assess the effect of RASi on short-term (≤30 days) and long-term (≥1 year) mortality in patients with AS.ResultsA total of 11 studies were included in the meta-analysis. Our results demonstrated that RASi reduced short-term mortality (OR = 0.76, 95% CI 0.63–0.93, p = 0.008) after aortic valve replacement (AVR). Subgroup analysis revealed that RASi was still associated with lower short-term mortality after transcatheter aortic valve replacement (TAVR); however, the association was relatively weak in patients who underwent surgical aortic valve replacement (SAVR). For long-term mortality, the pooled OR was 1.04 (95% CI 0.88–1.24, p = 0.63) after sensitivity analysis in patients who did not undergo AVR. In addition, our study confirmed that RASi significantly reduced long-term mortality (OR = 0.57, 95% CI 0.44–0.74, p < 0.0001) in patients who underwent AVR. Subgroup analysis showed that both TAVR and SAVR groups treated with RASi had lower long-term mortality.ConclusionRenin–angiotensin system inhibitors did not change long-term mortality in AS patients who did not undergo AVR. However, RASi reduced short- and long-term mortality in patients who underwent AVR

Remnant cholesterol is associated with cardiovascular mortality

Background: Genetic, observational, and clinical intervention studies indicate that circulating levels of remnant cholesterol (RC) are associated with cardiovascular diseases. However, the predictive value of RC for cardiovascular mortality in the general population remains unclear. Methods: Our study population comprised 19,650 adults in the United States from the National Health and Nutrition Examination Survey (NHANES) (1999–2014). RC was calculated from non-high-density lipoprotein cholesterol (non-HDL-C) minus low-density lipoprotein cholesterol (LDL-C) determined by the Sampson formula. Multivariate Cox regression, restricted cubic spline analysis, and subgroup analysis were applied to explore the relationship of RC with cardiovascular mortality. Results: The mean age of the study cohort was 46.4 ± 19.2 years, and 48.7% of participants were male. During a median follow-up of 93 months, 382 (1.9%) cardiovascular deaths occurred. In a fully adjusted Cox regression model, log RC was significantly associated with cardiovascular mortality [hazard ratio (HR) 2.82; 95% confidence interval (CI) 1.17–6.81]. The restricted cubic spline curve indicated that log RC had a linear association with cardiovascular mortality (p for non-linearity = 0.899). People with higher LDL-C (≥130 mg/dL), higher RC [≥25.7/23.7 mg/dL in males/females corresponding to the LDL-C clinical cutoff point (130 mg/dL)] and abnormal HDL-C (<40/50 mg/dL in males/females) levels had a higher risk of cardiovascular mortality (HR 2.18; 95% CI 1.13–4.21 in males and HR 2.19; 95% CI 1.24–3.88 in females) than the reference group (lower LDL-C, lower RC and normal HDL-C levels). Conclusions: Elevated RC levels were associated with cardiovascular mortality independent of traditional risk factors

Ruta de la gran pasión Argentina: un recurso turístico para Buenos Aires

Treball Final de Grau en Turisme. Codi: TU0944. Curs acadèmic: 2016-201

Incidence of New Onset Diabetes Mellitus Secondary to Acute Pancreatitis: A Systematic Review and Meta-Analysis

Background and Aims: Patients who have an episode of acute pancreatitis (AP) frequently develop diabetes mellitus (DM) over time. The reported incidence of DM after AP varies depending on the severity, etiology and the extent of pancreatic necrosis during AP. We performed a systematic review to determine the incidence of new-onset DM after AP episode (s), and compared the rate of DM in AP patients based upon different disease characteristics.Methods: A total of 31 relevant studies with 13894 subjects were collected from Medline, Embase, and Web of Science. Stata 15 software was used for data analyses in the meta-analysis.Results: The random-effects pooled incidence was 23.0% for DM (95% CI 16.0–31.0%) and 15.0% (95% CI 9.0–23.0%) for DM treated with insulin. We noted substantial heterogeneity in incidence estimates for DM and DM treated with insulin (I2 = 95.61 and 71.78%; both p &lt; 0·001). The DM incidence was higher in the populations that had a severe AP (SAP) episode than in those with mild acute pancreatitis (MAP) (39 vs. 14%). Patients that displayed pancreatic necrosis during the AP attack(s) had a higher frequency of DM than those without necrosis (37 vs. 11%). In addition, the pooled incidence of DM was higher after alcoholic compared to biliary AP (28 vs. 12%). The incidence of insulin use after SAP and alcoholic AP was 21 and 18%, respectively, with very low heterogeneities. According to duration of follow-up, the pooled rate of DM and insulin use within 5 years after AP was 20 and 14%, while the rate associated with follow-up duration of more than 5 years was elevated to 37 and 25%, respectively. On meta-regression, year of publication, male proportion, age at DM test, and duration of follow-up were neither positively nor negatively associated with the incidence of DM and DM treated with insulin in patients who had a prior AP attack.Conclusion: Patients with AP developed DM after discharge from hospital with a frequency of about 23%. SAP, alcoholic AP and acute necrotizing pancreatitis (ANP) were associated with increased incidence of DM. Assessments of severity, etiology, and pancreatic necrosis are critical for predicting DM development after AP