43 research outputs found

    Clinical Implication of Coronary Tortuosity in Patients with Coronary Artery Disease

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    Background: Coronary tortuosity (CT) is a common coronary angiography finding. The exact pathogenesis, clinical implication and long-term prognosis of CT are not fully understood. The purpose of this study is to investigate the clinical characteristics of CT in patients with suspected coronary artery disease(CAD) in a Chinese population. Methods: A total of 1010 consecutive patients underwent coronary angiography with complaints of chest pain or related symptoms were included in the present study (544 male, mean age: 64611 years). CT was defined by the finding of 3bends(definedas3 bends (defined as 45u change in vessel direction) along main trunk of at least one artery in systole and in diastole. Patients with or without CAD were further divided into CT-positive and CT-negative groups, all patients were followed up for the incidence of major adverse cardiovascular events (MACE) for 2 to 4 years. Results: The prevalence of CT was 39.1 % in this patient cohort and incidence of CT was significantly higher in female patients than that in male patients (OR = 2.603, 95%CI 1.897, 3.607, P,0.001). CT was positively correlated with essential hypertension (OR = 1.533, 95%CI 1.131, 2.076, P = 0.006) and negatively correlated with CAD (OR = 0.755, 95%CI 0.574, 0.994, P = 0.045). MACE during follow up was similar between CAD patients with or without CT. Conclusions: CT is more often seen in females and positively correlated with hypertension and negatively correlated wit

    Effect of a 180 mg ticagrelor loading dose on myocardial necrosis in patients undergoing elective percutaneous coronary intervention: A preliminary study

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    Background: To examine whether a loading dose of ticagrelor on top of clopidogrel reduced postpercutaneous coronary intervention (PCI) myonecrosis. Methods: Seventy seven coronary artery disease patients received a loading dose of 300 mg clopidogrel pre-PCI and were divided into three groups: group TT (n = 36): a loading dose of 180 mg ticagrelor pre-PCI, followed by ticagrelor 90 mg twice daily commencing one day post-PCI; group CT (n = 26): a maintenance dose of ticagrelor 90 mg twice daily; group CC (n = 15): clopidogrel 75 mg daily post- PCI. High sensitivity cardiac troponin T (hs-cTnT) and creatine kinase-MB (CK-MB) were measured pre-PCI and 0 h, 2 h or 24 h post-PCI. Platelet aggregation was measured in a separate cohort of 54 coronary artery disease patients (35 diabetic and 19 non-diabetic patients). Results: There were no significant differences in hs-cTnT and CK-MB concentration among the three groups. In group TT, diabetic patients had significant higher Δhs-cTnT2h–0h than non-diabetic patients. In the second cohort, although baseline platelet aggregation was higher in diabetic than non-diabetic patients, platelet aggregation was comparable between diabetic and non-diabetic patients at 0 and 2 h post-PCI. Conclusions: This study indicates that a loading dose of ticagrelor does not significantly reduce post- PCI myonecrosis. Diabetes is associated with more post-PCI myonecrosis. A loading dose of ticagrelor effectively reduces platelet aggregation in diabetic patients.

    Short-term traffic flow prediction based on whale optimization algorithm optimized BiLSTM_Attention

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    With the growths in population and vehicles, traffic flow becomes more complex and uncertain disruptions occur more often. Accurate prediction of urban traffic flow is important for intelligent decision-making and warning, however, remains a challenge. Many researchers have applied neural network methods, such as convolutional neural networks and recurrent neural networks, for traffic flow prediction modeling, but training the conventional network that can obtain the best network parameters and structure is difficult, different hyperparameters lead to different network structures. Therefore, this article proposes a traffic flow prediction model based on the whale optimization algorithm (WOA) optimized BiLSTM_Attention structure to solve this problem. The traffic flow is predicted first using the BiLSTM_Attention network which is then optimized by using the WOA to obtain its four best parameters, including the learning rate, the training times, and the numbers of the nodes of two hidden layers. Finally, the four best parameters are used to build a WOA_BiLSTM_Attention model. The proposed model is compared with both conventional neural network model and neural network model optimized by the WOA. Based on the evaluation metrics of MAPE, RMSE, MAE, and R2, the WOA_BiLSTM_Attention model proposed in this article presents the best performance.©2022 Wiley. This is the peer reviewed version of the following article: Xu, X., Liu, C., Zhao, Y. & Lv, X. (2022). Short-term traffic flow prediction based on whale optimization algorithm optimized BiLSTM_Attention. Concurrency and Computation: Practice and Experience 34(10), e6782, which has been published in final form at https://doi.org/10.1002/cpe.6782. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.fi=vertaisarvioitu|en=peerReviewed

    Enhancement of Anti-Hypoxic Activity and Differentiation of Cardiac Stem Cells by Supernatant Fluids from Cultured Macrophages that Phagocytized Dead Mesenchymal Stem Cells

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    Background: Most mesenchymal stem cells (MSCs) die shortly after transplantation into a myocardial infarcted area. Dead MSCs (dMSCs) are phagocytized by macrophages (pMΦ) in vivo and in vitro; however, the effects of pMΦ on cardiac stem cells (CSCs) remain unknown. Methods: MSCs, CSCs, and macrophages were obtained from bone marrow, hearts, and peritoneal cavity of mice, respectively. dMSCs were harvested after hypoxia for 24 h, and incubated with macrophages (2:1) for another 2 days with or without lipopolysaccharide (LPS, 50 ng/mL) and sorted by flow cytometry to obtain pMΦ. Viability and apoptosis of CSCs were respectively evaluated with the cell counting kit-8 (CCk-8) assay and Annexin V-PE/7-AAD staining at 0, 6, 12, and 24 h of culture with supernatant fluids from macrophages (MΦ), LPS-stimulated macrophages (LPS-pMΦ), pMΦ, and MSCs. GATA-4 and c-TnI expression was measured by flow cytometry on the seventh day. Expression of inflammation and growth factors was assessed by real-time polymerase chain reaction (RT-PCR) in MΦ, LPS-pMΦ, and pMΦ cells. Results: pMΦ expressed higher levels of interleukin-10 (IL-10) and transforming growth factor-β (TGF-β)and lower levels of tumor necrosis factor-α(TNF-α)and IL-6 than LPS-pMΦ, higher levels of growth factors and of GATA-4 and c-TnI at the 7th day, which were similar to those in MSCs. CSCs cultured with supernatant fluids of pMΦ exhibited higher proliferative, anti-hypoxic, and differentiation activities. Conclusion: The supernatant fluids of macrophages that had phagocytized dead MSCs encouraged changes in phenotype and growth factor expression, enhanced proliferation, differentiation, and anti-hypoxic activity of CSCs, which is relevant to understanding the persistent therapeutic effect of MSCs after their massive demise upon transplantation in myocardial infarction. Furthermore, some miRNAs or proteins which were extracted from the supernatant fluids may give us a new insight into the treatment of myocardial infarction in the future

    Research on the Stress Distribution Law of Fully Anchored Bolt and Analysis of Influencing Factors under the Condition of Surrounding Rock Deformation

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    As the mining depth increases, the deformation of the roadway becomes more difficult to control. As a main supporting structure for maintaining the stability of roadway, the fully anchored bolt is widely used to reinforce deep mine. At the same time, the analysis of the stress distribution law of fully anchored bolt is the basic work to optimize anchor design. Therefore, this paper establishes a fully anchored bolt-surrounding rock interaction model based on the law of surrounding rock deformation and derives the analytical expressions for the axial force and shear stress of the fully anchored bolt during normal support and critical failure. At the same time, the effects of surrounding rock properties, support resistance, and bolt length on the stress distribution of fully anchored bolt are analyzed. The results show that the stress distribution of fully anchored bolt is consistent with the “neutral point” theory and the most important is the fact that the conditions of surrounding rock, the supporting resistance, and the length of bolt affect the actual stress distribution of the fully anchored bolt. It provides a certain theoretical basis for the design and development of anchoring and supporting technology

    Impact of coronary tortuosity on coronary pressure: Numerical simulation study

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    Background: Coronary tortuosity (CT) is a common coronary angiographic finding. Whether CT leads to an apparent reduction in coronary pressure distal to the tortuous segment of the coronary artery is still unknown. The purpose of this study is to determine the impact of CT on coronary pressure distribution by numerical simulation. Methods: 21 idealized models were created to investigate the influence of coronary tortuosity angle (CTA) and coronary tortuosity number (CTN) on coronary pressure distribution. A 2D incompressible Newtonian flow was assumed and the computational simulation was performed using finite volume method. CTA of 30°, 60°, 90°, 120° and CTN of 0, 1, 2, 3, 4, 5 were discussed under both steady and pulsatile conditions, and the changes of outlet pressure and inlet velocity during the cardiac cycle were considered. Results: Coronary pressure distribution was affected both by CTA and CTN. We found that the pressure drop between the start and the end of the CT segment decreased with CTA, and the length of the CT segment also declined with CTA. An increase in CTN resulted in an increase in the pressure drop. Conclusions: Compared to no-CT, CT can results in more decrease of coronary blood pressure in dependence on the severity of tortuosity and severe CT may cause myocardial ischemia

    Path Planning and Bending Behaviors of 3D Printed Continuous Carbon Fiber Reinforced Polymer Honeycomb Structures

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    Continuous fiber reinforced polymer composites are widely used in load-bearing components and energy absorbers owing to their high specific strength and high specific modulus. The path planning of continuous fiber is closely related to its structural defects and mechanical properties. In this work, continuous fiber reinforced polymer honeycomb structures (CFRPHSs) with different printing paths were designed and fabricated via the fused deposition modeling (FDM) technique. The investigation of fiber dislocation at path corners was utilized to analyze the structural defects of nodes caused by printing paths. The lower stiffness nodes filled with pure polymer due to fiber dislocation result in uneven stiffness distribution. The bending performance and deformation modes of CFRPHSs with different printing paths and corresponding pure polymer honeycomb structures were investigated by three-point bending tests. The results showed that the enhancement effect of continuous fibers on the bending performance of honeycomb structures was significantly affected by the printing paths. The CFRPHSs with a staggered trapezoidal path exhibited the highest specific load capacity (68.33 ± 2.25 N/g) and flexural stiffness (627.70 ± 38.78 N/mm). In addition, the fiber distributions and structural defects caused by the printing paths determine the stiffness distribution of the loading region, thereby affecting the stress distribution and failure modes of CFRPHSs

    Progressive Failure and Fracture Mechanism of Sandstone under Hydraulic-Mechanical Coupling

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    Hydraulic coupling often leads to progressive rock failure accidents. Mechanical tests were performed over a range of combined pore water pressure and confining pressure stress path conditions to study the progressive failure characteristics of sandstone under hydraulic-mechanical coupling and explore the crack initiation and pore water fracture mechanism. The closure stress and damage stress were determined by the axial deformation stiffness and volume deformation stiffness. The experimental results indicate that confining pressure is the main controlling factor in the crack propagation stage, and pore water pressure enhances crack evolution. With increasing effective confining pressure, the effective peak deviatoric stress strongly increases and the characteristic stress increases linearly. The initiation stress and damage stress decrease with increasing pore water pressure. The moduli in stages I, II, and III are similar to the law of the transverse and radial deformation ratio with notable differences in stage IV. The fracture trend angle was determined by the ratio of axial crack strain and radial crack strain. Compared with the experimental results, the internal cracks in the sandstone samples are mainly type-II cracks, and type-I cracks are also locally present. After stress damage, the cracks expand and extend at an angle close to the real fracture

    Credit risk analysis of Chinese companies by applying the CAFÉ Approach

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    It is known that the current Credit Rating in financial markets of China is facing at least three problems: 1) the rating is falsely high; 2) the differentiation of credit rating is insufficient; and 3) the poor performance of predicting early warning, thus we must consider how to create a reasonable new credit risk analysis approach to deal with issues for financial markets in China for those listed companies’ performance. This report shows that by using a new method called the “Hologram approach” as a tool, we are able to establish a so-called “CAFÉ Risk Analysis System” (in short, “CAFÉ Approach”, or “CAFÉ”) to resolve three issues for credit rating in China. In particular, the main goal in this paper is to give a comprehensive report for credit risk assessments for eight selected list companies by applying our “CAFÉ” from different industry sectors against actual market performance with the time period from the past one to three years through our one-by-one interpretation for event screening and true occurrence and related events. In this way, we show how “CAFÉ” is able to resolve current three major problems of “rating is falsely high, the differentiation of credit rating grades is insufficient, and the poor performance of predicting early warning” in the current credit market in China’s financial industry in practice
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