Seismic Performance Assessment of Water Distribution Systems Based on Multi-Indexed Nodal Importance

open access articleSeismic performance assessment of water distribution systems (WDSs) based on hydraulic simulation is essential for resilience evaluation of WDSs under earthquake disasters. The assessment is mainly to determine how the water supply will be affected due to pipe breaks caused by the earthquake, with the water supply loss estimated based on the loss of supply to nodes. Existing research works usually use the average or overall performance metric of all user nodes as the system performance indicator without considering user nodes' individual performance and criticality. This paper proposes a framework to evaluate the importance of user nodes considering post-earthquake rescue service and the seismic performance of individual user nodes in the WDS, which supports the pipeline renovation plan to improve the performance of critical user nodes. The importance of user nodes is evaluated by a multi-index model, including the indices for daily service, post-earthquake rescue service, and network topology influence of user nodes. These indices evaluate the importance of user nodes in terms of their roles for daily water service, emergent rescue service, and water transmission to other nodes, respectively. Fragility model of pipelines evaluates the earthquake-induced damages of the WDS, and the seismic performance assessment of the WDS system is performed by the hydraulic model of the WDS with pipeline damages. The proposed framework is implemented in an actual WDS; the results show that the importance classification to user nodes by multi-index approach can identify the critical user nodes for post-earthquake rescue service, which traditional methods may ignore. The importance classification and seismic performance of individual user nodes make it feasible to check the seismic performance of critical user nodes and formulate a targeted pipeline renovation plan to focus limited resources on critical user nodes

Mechanical thrombectomy with intra-arterial alteplase provided better functional outcomes for AIS-LVO: a meta-analysis

BackgroundSeveral clinical trials have shown that intra-arterial thrombolysis using alteplase during mechanical thrombectomy (MT) has a better outcome than MT alone in ischemic stroke management. We performed the current meta-analysis to estimate the efficacy and safety of MT with intra-arterial alteplase therapy.MethodsThe MEDLINE, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched up to Mar. 2022 to identify the clinical trials that compared MT alone versus MT with intra-arterial alteplase therapy. STATA 16.0 was used for statistical analysis. The odds ratios (ORs) and 95% confidence intervals (95%CIs) were calculated with a random effect model.ResultsSeven studies involving 1,083 participants were included. The primary outcomes were better functional outcomes, defined as a modified Rankin Scale (mRS) score between 0 and 2 at 90  days, and successful recanalization, defined as a modified thrombolysis in cerebral infarction (mTICI) score  ≥  2b. Compared to MT alone, MT with intra-arterial alteplase did not lead to higher mTICI scores (OR 1.58, 95%CI 0.94 to 2.67, p = 0.085, I2 = 16.8%) but did lead to better mRS (OR 1.37, 95%CI 1.01 to 1.86, p = 0.044). There was no increase in mortality or bleeding events in the overall or subgroup analyses.ConclusionMT with intra-arterial alteplase did not improve the recanalization rate but provided better functional outcomes. The intervention did not increase adverse effects in any subgroup at the same time.Clinical trial registrationhttp://inplasy.com, identifier INPLASY202240027

Nonlinear Solid–Fluid Coupled Seismic Response Analysis of Layered Liquefiable Deposit

A seismic response analysis of layered, liquefiable sites plays an important role in the seismic design of both aboveground and underground structures. This study presents a detailed dynamic site response analysis procedure with advanced nonlinear soil constitutive models for non-liquefiable and liquefiable soils in the OpenSees computational platform. The stress ratio controlled, bounding surface plasticity constitutive model, PM4Sand, is used to simulate the nonlinear response of the liquefiable soil layers subjected to two seismic ground motions with different characteristics. The nonlinear hysteretic behavior of the non-liquefiable soil under earthquake excitations is captured by the Pressure Independent Multi Yield kinematic plasticity model with a von Mises multi-yield surface. The soil elements are modelled utilizing the solid–fluid fully coupled plane-strain u-p elements. The seismic response of the layered liquefiable site in terms of the development of excess pore water pressure, acceleration, ground surface settlement, and stress–strain and effective stress path time histories under two representative earthquake excitations are investigated in this study. The numerical results indicate that both the characteristics of ground motions and the site profile have a significant influence on the dynamic response of the layered liquefiable site. Under the same intensity of ground motion, the loose sand layer with a 35% relative density is more prone to liquefaction and contractive deformation, which causes irreversible residual deformation and vertical settlement. The saturated soil layer can effectively filter the high-frequency components and amplify the low-frequency components of ground motions. Moreover, the liquified site produces a 40% post-earthquake consolidation settlement after the excess pore pressure dissipation

Nonlinear Solid–Fluid Coupled Seismic Response Analysis of Layered Liquefiable Deposit

A seismic response analysis of layered, liquefiable sites plays an important role in the seismic design of both aboveground and underground structures. This study presents a detailed dynamic site response analysis procedure with advanced nonlinear soil constitutive models for non-liquefiable and liquefiable soils in the OpenSees computational platform. The stress ratio controlled, bounding surface plasticity constitutive model, PM4Sand, is used to simulate the nonlinear response of the liquefiable soil layers subjected to two seismic ground motions with different characteristics. The nonlinear hysteretic behavior of the non-liquefiable soil under earthquake excitations is captured by the Pressure Independent Multi Yield kinematic plasticity model with a von Mises multi-yield surface. The soil elements are modelled utilizing the solid–fluid fully coupled plane-strain u-p elements. The seismic response of the layered liquefiable site in terms of the development of excess pore water pressure, acceleration, ground surface settlement, and stress–strain and effective stress path time histories under two representative earthquake excitations are investigated in this study. The numerical results indicate that both the characteristics of ground motions and the site profile have a significant influence on the dynamic response of the layered liquefiable site. Under the same intensity of ground motion, the loose sand layer with a 35% relative density is more prone to liquefaction and contractive deformation, which causes irreversible residual deformation and vertical settlement. The saturated soil layer can effectively filter the high-frequency components and amplify the low-frequency components of ground motions. Moreover, the liquified site produces a 40% post-earthquake consolidation settlement after the excess pore pressure dissipation

Evaluation of a Current Vehicle Load Model Using Weigh-in-Motion Records: A Case in China

In order to assess the vehicle load carrying capacity of existing bridges on the national highway G103 in Beijing, the vehicle load model for the practical traffic flow conditions needs to be determined. Based on the traffic axle load data measured by the weigh-in-motion system and the methods proposed by General Code for Design of Highway Bridges and Culverts (JTG D60-2004) and Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts (JTG D62-2004), the vehicle load parameters under practical traffic flow conditions are investigated. A typical 6-axle vehicle model with a 2-1-3 axial pattern is proposed by using the statistical analysis of total weight, axial weight, etc. The live load effects of Daliushu No. 2 Bridge, one highway bridge on the national highway G103, are analyzed using the proposed model and compared to the vehicle load model given in the Chinese code. The results show that there are great differences in the vehicle load parameters and the live load effects from the proposed vehicle load model increased by 20–50% compared with the model given by the code. The overweight vehicles are potential threats to the safety of existing bridges

Experimental study on out-of-plane seismic performance of precast composite sidewalls of utility tunnel with grouting-sleeve joints

The precast composite reinforced concrete wall with the advantages of fewer joints, superior impermeability and rapid construction provides an efficient and environmental friendly alternative in the construction of underground utility tunnels in the last few years. To investigate the seismic performance of precast concrete composite walls of utility tunnels with grouting-sleeve connection under out-of-plane loads, a series of quasi-static cyclic tests were performed on the full-scale sidewall specimens with different axial compression ratios in this study. The experimental results including the failure modes, crack distributions, and the influence of different connections on the out-of-plane seismic performance of precast concrete composite wall were carefully examined and compared with those from the cyclic tests of the cast-in-place sidewalls of the utility tunnel. The test results show that the seismic performance of the precast concrete composite sidewall specimen, such as the hysteresis curves, the ultimate bearing capacity, stiffness degradation pattern and the ductility ratio, is basically the same as that of the cast-in-place specimen, indicating that the seismic performance of the prefabricated structure is equivalent to that of the cast-in-place structure. Moreover, the grouting-sleeves of the joints can effectively transfer the reinforcement stress until the failure of the precast concrete composite sidewall specimens, which exhibits excellent out-of-plane ductility and serviceability

The impact of COVID-19 on clinical outcomes in people undergoing neurosurgery: a systematic review and meta-analysis

Abstract Background The coronavirus disease-2019 (COVID-19) pandemic has created a global crisis unique to the healthcare system around the world. It also had a profound impact on the management of neurosurgical patients. In our research, we investigated the effect of the COVID-19 pandemic on clinical outcomes in people undergoing neurosurgery, particularly vascular and oncological neurosurgery. Method Two investigators independently and systematically searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrail.Gov, and Web of Science to identify relevant studies respecting the criteria for inclusion and exclusion published up to June 30, 2022. The outcomes of our research included mortality rate, length of stay, modified Rankin Score, delay in care, Glasgow outcome scale, and major complications. The risk of bias was assessed using the Methodological Index for Non-randomized Studies (MINORS) checklist. Results Two investigators independently and systematically searched 1378 results from MEDLINE, EMBASE, Cochrane database, ClinicalTrail.Gov, and Web of Science and extracted the detailed data from 13 studies that met the review’s eligibility criteria. Two articles reported on patients with intracerebral hemorrhages, five on patients with subarachnoid hemorrhages, four on patients undergoing surgery for neuro-oncology, and in two studies the patients’ conditions were unspecified. A total of 26,831 patients were included in our research. The number who died was significantly increased in the COVID-19 pandemic group (OR 1.52, 95% CI 1.36–1.69, P < 0.001). No significant difference was found between the two groups in terms of length of stay (SMD − 0.88, 95% CI − 0.18–0.02, P = 0.111), but it differed between regions, according to our subgroup analysis. Conclusion Compared to the pre-pandemic group, the number who died was significantly increased in the COVID-19 pandemic group. Meanwhile, the effect of the pandemic on clinical outcomes in people undergoing neurosurgery might differ in different regions, according to our subgroup analysis

The FDA-approved anti-amyloid-β monoclonal antibodies for the treatment of Alzheimer’s disease: a systematic review and meta-analysis of randomized controlled trials

Abstract Background Alzheimer’s disease (AD) is a worldwide public health problem and is difficult to cure. Drugs aimed at slowing the progression of the disease have been developed, with the Food and Drug Administration (FDA) granting accelerated approval for aducanumab on June 21, 2021 and a new accelerated approval for lecanemab on January 22, 2023. We performed this systematic review and meta-analysis to assess the efficacy and safety of FDA-approved anti-amyloid-β (anti-Aβ) monoclonal antibodies (mabs) for the treatment of AD. Method PubMed, Embase, and Cochrane Library were systematically searched to identify relevant studies published before May 2023. Efficacy outcomes included Aβ, neuroimaging, and biomarker outcomes. Safety outcomes included amyloid-related imaging abnormalities with edema or effusions (ARIA-E) and ARIA with cerebral microhemorrhages, cerebral macrohemorrhages, or superficial siderosis (ARIA-H). Review Manager 5.4 software was used to assess the data. The standard mean differences (SMDs) or odds ratio (OR) with 95% confidence interval (95% CI) were analyzed and calculated with a random effect model or a fixed effect model. Result Overall, 4471 patients from 6 randomized controlled trials (RCTs), with 2190 patients in the treatment group and 2281 patients in the placebo group meeting the inclusion criteria. FDA-approved anti-Aβ mabs showed statistically significant improvements in clinical outcomes, including CDR-SB (P = 0.01), ADCS-ADL-MCI (P = 0.00003), ADCOMS (P < 0.00001), ADAS-Cog (P < 0.00001). Moreover, FDA-approved anti-Aβ mabs increased cerebrospinal fluid (CSF) Aβ1-42 (P = 0.002) and plasma Aβ42/40 ratios (P = 0.0008). They also decreased CSF P-Tau (P < 0.00001), CSF T-Tau (P < 0.00001), and plasma p-tau181 (P < 0.00001). FDA-approved anti-Aβ mabs perform neuroimaging changes in amyloid Positron Emission Tomography Standardized Uptake Value ratio (PET SUVr) (P < 0.00001). However, compared with placebo, FDA-approved anti-Aβ mabs had higher risk of ARIA-E (P < 0.00001) and ARIA-H (P < 0001). Conclusion FDA-approved anti-Aβ mabs have a role in slowing disease progression in patients with AD, at the cost of an increased probability of side effects