16 research outputs found

    Flutter reliability analysis of Xiangshan Harbor Highway Cable-Stayed Bridges in Service

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    With the development of bridge structures towards being light weight and having a large span , the overall flexibility, and, hence, wind sensitivity, of the bridge increases. Flutter is one of the pivotal factors considered in the design and operation stage for long-span cable-stayed bridges due to its devastating impact, often intrigued by relatively low instability caused by wind speed. This paper presents a reliability theory-based numerical analysis on bridge flutter stability and its influence law of key parameters using a real bridge, the Xiangshan Harbor highway cable-stayed bridge in China. The analysis starts with creating a full scale of finite element model for the bridge in service to calculate the flutter derivative and time-dominated combining rational function in order to obtain the critical-flutter wind speed, and then the aerodynamic self-excited forces on the bridge and flutter time-history response are calculated to identify the flutter critical wind speed. Further, the influence of key parameters for flutter reliability, including the stiffness of the main girder, wire breaking rate, damping ratio and cable breakage location are analyzed comprehensively to achieve the change law of critical flutter wind speed with these parameters. Considering the uncertainty of the actual parameters, these parameters are taken as random variables, and the reliability index and failure probability of bridge flutter are calculated according to their probability distribution and the Latin hypercube sampling method. On this basis, a few suggestions are put forward for flutter risk-control during the service of this cable-stayed bridge, which can further enhance the design theory for long-span flexible bridges

    Projected Effects of Climate Change on Species Range of <i>Pantala flavescens</i>, a Wandering Glider Dragonfly

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    Dragonflies are sensitive to climate change due to their special habitat in aquatic and terrestrial environments, especially Pantala flavescens, which have extraordinary migratory abilities in response to climate change on spatio-temporal scales. At present, there are major gaps in the documentation of insects and the effects of climatic changes on the habitat and species it supports. In this study, we model the global distribution of a wandering glider dragonfly, P. flavescens, and detected the important environmental factors shaping its range, as well as habitat shifts under historical and future warming scenarios. The results showed a global map of species ranges of P. flavescens currently, including southern North America, most of South America, south-central Africa, most of Europe, South, East and Southeast Asia, and northern Oceania, in total, ca. 6581.667 × 104 km2. BIO5 (the max temperature of warmest month) and BIO13 (the precipitation of wettest month) greatly explained its species ranges. The historic refugia were identified around the Great Lakes in the north-central United States. Future warming will increase the total area of suitable habitat and shift the type of suitable habitat compared to the current distribution. The habitat suitability of P. flavescens decreased with elevation, global warming forced it to expand to higher elevations, and the habitat suitability of P. flavescens around the equator increased with global warming. Overall, our study provides a global dynamic pattern of suitable habitats for P. flavescens from the perspective of climate change, and provides a useful reference for biodiversity research and biological conservation

    Projected Effects of Climate Change on Species Range of Pantala flavescens, a Wandering Glider Dragonfly

    No full text
    Dragonflies are sensitive to climate change due to their special habitat in aquatic and terrestrial environments, especially Pantala flavescens, which have extraordinary migratory abilities in response to climate change on spatio-temporal scales. At present, there are major gaps in the documentation of insects and the effects of climatic changes on the habitat and species it supports. In this study, we model the global distribution of a wandering glider dragonfly, P. flavescens, and detected the important environmental factors shaping its range, as well as habitat shifts under historical and future warming scenarios. The results showed a global map of species ranges of P. flavescens currently, including southern North America, most of South America, south-central Africa, most of Europe, South, East and Southeast Asia, and northern Oceania, in total, ca. 6581.667 &times; 104 km2. BIO5 (the max temperature of warmest month) and BIO13 (the precipitation of wettest month) greatly explained its species ranges. The historic refugia were identified around the Great Lakes in the north-central United States. Future warming will increase the total area of suitable habitat and shift the type of suitable habitat compared to the current distribution. The habitat suitability of P. flavescens decreased with elevation, global warming forced it to expand to higher elevations, and the habitat suitability of P. flavescens around the equator increased with global warming. Overall, our study provides a global dynamic pattern of suitable habitats for P. flavescens from the perspective of climate change, and provides a useful reference for biodiversity research and biological conservation

    Multiple Developmental Defects in sox11a Mutant Zebrafish with Features of Coffin-Siris Syndrome

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    A previous study suggested that human Coffin-Siris syndrome is related to the mutation of SOX11. Since the homozygous SOX11 mutant mice died soon after birth, no suitable model was available for the study of the pathogenic mechanism of Coffin-Siris syndrome. To solve this problem, we generated two viable homozygous zebrafish mutants, sox11a(m/m) and sox11b(m/m). We found that the sox11a(m/m) mutant possessed Coffin-Siris syndrome features. The sox11a(m/m) mutants exhibited growth deficiency from 3.3 hpf embryos to adulthood. Furthermore, the sox11a(m/m) mutant also displayed microcephaly, narrow pupillary distance, achondroplasia, and bone deformity in adults. Growth deficiency could be rescued by the injection of sox11a mRNA at the one-cell stage. In addition, the expression levels of genes related to cartilage and bone were downregulated in the sox11a(m/m) mutant, indicating that sox11a mainly affected the growth and development of zebrafish by regulating the expression of genes related to skeletal development. Our results indicate that sox11a(m/m) mutant zebrafish offered a potential model system to help with the search for pathogenic mechanisms of human Coffin-Siris syndrome

    Facile Synthesis of FeCoNiCuIr High Entropy Alloy Nanoparticles for Efficient Oxygen Evolution Electrocatalysis

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    The lack of an efficient and stable electrocatalyst for oxygen evolution reaction (OER) greatly hinders the development of various electrochemical energy conversion and storage techniques. In this study, we report a facile synthesis of FeCoNiCuIr high-entropy alloy nanoparticles (HEA NPs) by a one-step heat-up method. The involvement of glucose made the NPs grow uniformly and increased the valence of Ir. The resulting FeCoNiCuIr NPs exhibit excellent OER performance in alkaline solution, with a low overpotential of 360 mV to achieve a current density of 10 mA cm−2 at a Tafel slope of as low as 70.1 mV dec−1. In addition, high stability has also been observed, which remained at 94.2% of the current density after 10 h constant electrolysis, with a constant current of 10 mA cm−2. The high electrocatalytic activity and stability are ascribed to the cocktail effect and synergistic effect between the constituent elements. Our work holds the potential to be extended to the design and synthesis of high-performance electrocatalysts

    Facile Synthesis of FeCoNiCuIr High Entropy Alloy Nanoparticles for Efficient Oxygen Evolution Electrocatalysis

    No full text
    The lack of an efficient and stable electrocatalyst for oxygen evolution reaction (OER) greatly hinders the development of various electrochemical energy conversion and storage techniques. In this study, we report a facile synthesis of FeCoNiCuIr high-entropy alloy nanoparticles (HEA NPs) by a one-step heat-up method. The involvement of glucose made the NPs grow uniformly and increased the valence of Ir. The resulting FeCoNiCuIr NPs exhibit excellent OER performance in alkaline solution, with a low overpotential of 360 mV to achieve a current density of 10 mA cm&minus;2 at a Tafel slope of as low as 70.1 mV dec&minus;1. In addition, high stability has also been observed, which remained at 94.2% of the current density after 10 h constant electrolysis, with a constant current of 10 mA cm&minus;2. The high electrocatalytic activity and stability are ascribed to the cocktail effect and synergistic effect between the constituent elements. Our work holds the potential to be extended to the design and synthesis of high-performance electrocatalysts

    Gnrh3 Regulates PGC Proliferation and Sex Differentiation in Developing Zebrafish

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    Gonadotropin-releasing hormone (Gnrh) plays important roles in reproduction by stimulating luteinizing hormone release, and subsequently ovulation and sperm release, ultimately controlling reproduction in many species. Here we report on a new role for this decapeptide. Surprisingly, Gnrh3-null zebrafish generated by CRISPR/Cas9 exhibited a male-biased sex ratio. After the dome stage, the number of primordial germ cells (PGCs) in gnrh3(-/-) fish was lower than that in wildtype, an effect that was partially rescued by gnrh3 overexpression. A terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) analysis revealed no detectable apoptosis of PGCs in gnrh3(-/-) embryos. Proliferating PGCs could be detected in wild-type embryos, while there was no detectable signal in gnrh3(-/-) embryos. Compared with wild type, the phosphorylation of AKT was not significantly different in gnrh3(-/-) embryos, but the phosphorylation of ERK1/2 decreased significantly. Treatment with a Gnrh analog (Alarelin) induced ERK1/2 phosphorylation and increased PGC numbers in both wild-type and gnrh3(-/-) embryos, and this was blocked by the MEK inhibitor PD0325901. The relative expression of sox9a, amh, and cyp11b were significantly upregulated, while cyp19a1a was significantly downregulated at 18 days post-fertilization in gnrh3(-/-) zebrafish. Taken together, these results indicate that Gnrh3 plays an important role in early sex differentiation by regulating the proliferation of PGCs through a MAPK-dependent path.</p

    Improvement in clinical and economic outcomes with empiric antibiotic therapy covering atypical pathogens for community-acquired pneumonia patients: a multicenter cohort study

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    Objective: To determine the effectiveness of empiric antibiotic regimens covering atypical pathogens with respect to detailed clinical and economic outcomes in community-acquired pneumonia (CAP). Methods: A population-based, multicenter, retrospective cohort study was conducted from June 2010 to May 2011. Patients with a diagnosis of CAP were enrolled and categorized into two groups according to the initial antibiotic strategy used – covering or not covering atypical pathogens. Regression analysis was performed to assess their clinical outcomes (all-cause mortality, clinical improvement rate after 72 h of antimicrobial therapy, and clinical cure rate) and economic outcomes (length of stay, hospitalization costs, and antibiotic expenditure). Results: A total of 827 patients met the criteria for CAP; 561 (67.8%) received antibiotics with atypical pathogen coverage (APC group), while 266 (32.2%) did not (non-APC group). Regression analysis revealed that the all-cause mortality was much lower in the APC group than in the non-APC group (0.9% vs. 4.9%, respectively), with an odds ratio (OR) of 0.18 (95% confidence interval (CI) 0.06–0.49). Clinical improvement at 72 h (87.7% vs. 85.0%, p = 0.274) and the clinical cure rate (91.1% vs. 88.3%, p = 0.213) were more favorable in the APC group, but with no significant difference compared to the non-APC group. Moreover, the APC group had a shorter mean length of stay (APC 10.2 days vs. non-APC 11.6 days, p < 0.001). In addition, the mean total hospitalization costs for the APC group were markedly lower compared with the non-APC group (US1172.7vs.US 1172.7 vs. US 1510.7; p < 0.001). Conclusion: Antimicrobial treatment covering atypical pathogens for hospitalized CAP patients is associated with reduced mortality and economic burden

    Table_2_Comparative efficacy and toxicity of immune checkpoint inhibitors in combination with or without chemotherapy treatment for advanced esophageal squamous cell carcinoma: A systematic review and meta-analysis.docx

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    IntroductionWe did a systematic review and meta-analysis to assess the efficacy and safety of immune checkpoint inhibitors combined with or without chemotherapies in patients with esophageal squamous cell carcinoma.MethodsData related to the treatment of esophageal squamous cell carcinoma with immune checkpoint inhibitors therapy were retrieved from the database construction to August 2022. The risk of bias was assessed using the Cochrane Manual standard and RevMan 5.3 software for data synthesis. The outcome measures observed included overall survival, 12-month survival, disease control rate, objective response rate, treatment-related adverse events of grade 3 or higher, and progression-free survival. The adverse reactions included fatigue, diarrhea, hypothyroidism, rash, anemia, and anorexia.ResultsIn this meta-analysis, a total of 17 randomized controlled trials were included. In first-line therapy, immune checkpoint inhibitors combined with or without chemotherapy in the treatment of esophageal squamous cell carcinoma was more effective than chemotherapy alone. Overall survival, 12-month survival rate, and objective response rate were statistically significant. Among second-line treatments, immune checkpoint inhibitors combined with or without chemotherapy in the treatment of esophageal squamous cell carcinoma had statistically significant overall survival, 12-month survival, objective response rate, treatment-related adverse events of grade 3 or higher, and progression-free survival compared with chemotherapy alone.ConclusionBoth first- and second-line immune checkpoint inhibitors are effective for esophageal squamous cell carcinoma, and the adverse reactions are controllable and safe.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021282586.</p

    Table_1_Comparative efficacy and toxicity of immune checkpoint inhibitors in combination with or without chemotherapy treatment for advanced esophageal squamous cell carcinoma: A systematic review and meta-analysis.docx

    No full text
    IntroductionWe did a systematic review and meta-analysis to assess the efficacy and safety of immune checkpoint inhibitors combined with or without chemotherapies in patients with esophageal squamous cell carcinoma.MethodsData related to the treatment of esophageal squamous cell carcinoma with immune checkpoint inhibitors therapy were retrieved from the database construction to August 2022. The risk of bias was assessed using the Cochrane Manual standard and RevMan 5.3 software for data synthesis. The outcome measures observed included overall survival, 12-month survival, disease control rate, objective response rate, treatment-related adverse events of grade 3 or higher, and progression-free survival. The adverse reactions included fatigue, diarrhea, hypothyroidism, rash, anemia, and anorexia.ResultsIn this meta-analysis, a total of 17 randomized controlled trials were included. In first-line therapy, immune checkpoint inhibitors combined with or without chemotherapy in the treatment of esophageal squamous cell carcinoma was more effective than chemotherapy alone. Overall survival, 12-month survival rate, and objective response rate were statistically significant. Among second-line treatments, immune checkpoint inhibitors combined with or without chemotherapy in the treatment of esophageal squamous cell carcinoma had statistically significant overall survival, 12-month survival, objective response rate, treatment-related adverse events of grade 3 or higher, and progression-free survival compared with chemotherapy alone.ConclusionBoth first- and second-line immune checkpoint inhibitors are effective for esophageal squamous cell carcinoma, and the adverse reactions are controllable and safe.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021282586.</p
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