Search

Background and AimsThe reported incidence of arterial thromboembolism (ATE) and venous thromboembolism (VTE) after cancer varies. A meta-analysis was performed to define the incidence of thromboembolism (TE) in cancer patients.MethodsArticles were searched in PubMed and Embase from inception to November 1, 2022. Studies reporting the incidence data or data from which incidence could be estimated among patients with cancer and the explicit follow-up duration were included.ResultsSeventy-four studies involving 5059134 cancer patients were identified. The incidence rate per 1000 person-years was 11.60 (95% CI 7.62-15.58) for ATE, 6.11 (95% CI 3.70-8.53) for myocardial infarction, 9.07 (95% CI 7.48-10.66) for ischemic stroke, 2.11 (95% CI 0.89-3.31) for another ATE, 26.32 (95% CI 24.46-28.18) for VTE, 12.69 (95% CI 11.51-13.87) for deep vein thrombosis, 5.94 (95% CI 5.29-6.59) for pulmonary embolism, and 13.18 (95% CI 9.93-16.42) for another VTE. In addition, the highest incidence of ATE was observed in patients with gastrointestinal cancer, while patients with pancreatic cancer had the highest incidence of VTE. The risk of ATE and VTE increased at the initial stage of cancer, and then declined and became non-significant.ConclusionThis meta-analysis provided overall estimates of ATE and VTE incidence in cancer patients, adding an important insight into the trajectory of the development of TE in cancer patients, which could help reduce the risk of TE in cancer patients in the future.

Both aldosterone and arginine vasopressin (AVP) are produced in the heart and may participate in cardiac fibrosis. However, their relationship remains unknown. This study aims to demonstrate the regulation and role of AVP in aldosterone synthesis in the heart. Rats were subjected to a sham operation or myocardial infarction (MI) by ligating the coronary artery. Cardiac function and fibrosis were assessed using echocardiography and immunohistochemical staining, respectively. In addition, the effects of AVP stimulation on cardiac microvascular endothelial cells (CMECs) were studied using ELISA, real-time PCR, and Western blotting. Compared with the rats having undergone a sham operation, the MI rats had an increased LVMI, type I collagen composition, and concentrations of aldosterone and AVP in the heart but decreased cardiac function. As the MI rats aged, the LVMI, type I collagen, aldosterone, and AVP increased, while the LVMI decreased. Furthermore, AVP time-dependently induced aldosterone secretion and CYP11B2 mRNA expression in CMECs. The p-CREB levels were significantly increased by AVP. Nevertheless, these effects were completely blocked by SR49059 or partially inhibited by KN93. This study demonstrated that AVP could induce the secretion of local cardiac aldosterone, which may involve CaMK and CREB phosphorylation and CYP11B2 upregulation through V1 receptor activation.

Background Although silent myocardial infarction (SMI) is prognostically important, the risk of sudden cardiac death (SCD) among patients with incident SMI is not well established. Methods and Results We examined 2 community‐based cohorts: the ARIC (Atherosclerosis Risk in Communities) study (n=13 725) and the CHS (Cardiovascular Health Study) (n=5207). Incident SMI was defined as electrocardiographic evidence of new myocardial infarction during follow‐up visits that was not present at the baseline. The primary study end point was physician‐adjudicated SCD. In the ARIC study, 513 SMIs, 441 clinically recognized myocardial infarctions (CMIs), and 527 SCD events occurred during a median follow‐up of 25.4 years. The multivariable hazard ratios of SMI and CMI for SCD were 5.20 (95% CI, 3.81–7.10) and 3.80 (95% CI, 2.76–5.23), respectively. In the CHS, 1070 SMIs, 632 CMIs, and 526 SCD events occurred during a median follow‐up of 12.1 years. The multivariable hazard ratios of SMI and CMI for SCD were 1.70 (95% CI, 1.32–2.19) and 4.08 (95% CI, 3.29–5.06), respectively. The pooled hazard ratios of SMI and CMI for SCD were 2.65 (2.18–3.23) and 3.99 (3.34–4.77), respectively. The risk of SCD associated with SMI is stronger with White individuals, men, and younger age. The population‐attributable fraction of SCD was 11.1% for SMI, and SMI was associated with an absolute risk increase of 8.9 SCDs per 1000 person‐years. Addition of SMI significantly improved the predictive power for both SCD and non‐SCD. Conclusions Incident SMI is independently associated with an increased risk of SCD in the general population. Additional research should address screening for SMI and the role of standard post–myocardial infarction therapy.

Plunge milling cutter withstanding greater loads in heavy milling can cause tool breakage, cutting vibration, even chatter. Firstly, geometric model of plunge milling cutter on various combinations of axial rake angle and radial rake angle are established. Secondly, with combination different axial rake angle and radial rake angle of plunge milling cutter under static load, the amount of deformation plunge milling cutter are calculated by finite element analysis. Finally, the plunge milling cutter first six natural frequencies are given in plunge milling cutter modal analysis with finite element analysis. The results show that minimum total deformation of plunge milling cutter is given with the axial rake angle 5° and radial rake angle-5 ° of the cutter and when the tool working at frequencies up to 10012HZ has caused vibration within the XY plane.

With pelton turbines and other complex three-dimensional structure cavities that contains various shaped surfaces and all kinds of larger curvature, the three-axis CNC machine with a tool rotary to achieve the four coordinate overall Pelton CNC machining. According to processing characteristics of pelton runner, the paper determines the selection of materials and the overall structure of the tool. And the appropriate way of milling and milling parameters are made. The overall processing program and processing parameters of pelton runner are designed on this basis. The feasibility of the process and cutting route are verified by the simulation of cutting route and experiments.

Fir tree groove broaching is prone to deformation, which affects the machining precision of rear wheel groove. The numerical broaching force is calculated to improve deformation of the processed round tank .This paper uses the planer to make cutting tests that are carried out in shaping machine to simulate the wheel broaching process and measures the cutting force in the experiment. After analyzing the unit numerical cutting force of GH4698 broaching is finally obtained. It provides a simple method to calculate the cutting force of wheel groove machining.

In this paper, numerical simulation method is used to study the turning tool strength by Deform 3D in the process of rough machining high strength steel (2.25Cr-1Mo-0.25V).It mainly studies the effect of the feed rate on the cutting force. At the same time, non-uniform distribution cutting force got from the simulation results is taken as the numerical simulation mechanical load of turning tool blade strength to study the influence of feed rate on the turning tool strength. The simulation results show that: with the feed increasing, the mechanical load that turning tool blade bears increases. The maximum effective stress and displacement of the turning tool blade is also increased.

The three-dimensional finite element modeling and experimental validation of plunge milling of stainless steel (1Cr13) are presented. The commercial software Deform 3D applied for the finite element modeling is studied the effect of feed rate per tooth (fz) on the cutting forces and the temperature fields. The formation of chip in the finite element model is formed by local adaptive remeshing technique. The feed rate per tooth (fz) significantly affects the cutting forces, but slightly influences the maximum temperature of the chip.

Ni-based super-alloy GH4169 that is most widely used in aerospace is one of the most difficult-to-cut materials, which can be machined by Polycrystalline Cubic Boron Nitride (PCBN) tool. In this paper, the cutting process of super-alloy GH4169 with PCBN tool is researched by simulation, combing with the comparison and verification of experiment. The change rules of cutting temperature and force under different cutting parameters are obtained in this study. The reasonable parameter ranges of high efficiency cutting are proposed in cutting parameter optimization, in order to provide a reference for high efficiency machining of super-alloy GH4169 with PCBN tool.

The finite element modeling and experimental validation of three-dimensional heavy cutting of high strength steel (2.25Cr-1Mo-0.25V) are presented. The commercial software Deform 3D applied for the finite element modeling is studied the effect of feed rate on the principal cutting forces and the temperature fields. The friction between the tool and the chip is assumed to follow a shear model and the local adaptive remeshing technique is used for the formation of chip. The feed rate significantly affects the cutting forces, but slightly influences the maximum temperature of the chip. The simulation results are compared with experimental data and found to be in good agreement.

In this paper, the effects of cutting parameters and tool geometry parameters on the damaged layer were investigated with precision cutting of high strength alloy experiments. The mechanical and thermal effects on microstructure of sub-surfaces in precision turning high strength alloy are studied with a scanning electron microscope (SEM) analysis. A thin disturbed or plastically deformed layer is distinguished by the presence of grains that are elongated and rotated in the direction of cutting. No significant heat affected layer and phase transformation is found below the machined surface in all the tests. It also implies that mechanical deformation plays a larger role during precision turning.

In this paper, the effect of cutting parameters on cutting force, cutting temperature and surface roughness on cutting force, cutting temperature and surface roughness are experimentally studied in spray cutting GH4169 Ni-base superalloy used carbide cutting tools. The results showed that reasonable choice of cutting parameters can effective reduction of cutting force and cutting temperature, and improve the machining surface roughness. Thus realizing clean production mode.

Analyzing and researching the main failure forms of the hard alloy turning tool in rough machining process of the hydrogenated cylindrical shell’s blank. Then the cutting experiments were done at the site, and the results showed that the main failure forms of the hard alloy turning tool in rough machining process of the blank were tools’ fracture. However the main reason leading into this phenomenon was the mechanical impact of variable frequency and variable load which was caused by the dynamic change of cutting dosage. Integrating the experiment results, and combining the principles of elasticity and the principles of fracture toughness of hard alloy, the measures of protecting the tools from being fractured prematurely in heavy cutting process were worked out, then the research result would provide reference database for practical production.

The chatter between tool and workpiece has become a problem that urgently need to be solved in modern manufacturing system development.This paper analyzes the main factors in affecting the flutter when to turn ring groove of inner hole for large stainless steel thin-walled pieces. take normal direction of workpiece cutting surface as modeling direction, consider processing status of the large cylinder workpiece with large diameter, large height, small wall thickness and vertical large overhang. Based on vibration theory, establish a vibration dynamic mathematical model for large thin-walled parts in turning process, investigate the flutter in processing, provide a useful reference for solving the vibration problem of large cylinder parts in processing.

During precise hard cutting, back cutting depth and feed rate are relatively small. Study on the influence of PCBN (Polycrystalline Cubic Boron Nitride) cutting tools edge (chamfer edge or cutting edge radius) on cutting force is important. As the effect of cutting edge on mechanism of shear slip plane is very complicated, so to study the effect of consider cutting edge parameters and cutting parameters by genetic algorithm on cutting force, to build up cutting force model of precise hard cutting. It is feasible to predict cutting force by genetic algorithm with experiment.

Because the tube festivals surface is not round, uneven, so the cutting tool is under impact unceasingly in cutting process. Cutting tool is extremely easy to have fatigue failure, therefore it is very necessary to use finite element numerical analysis software ANSYS to carry on numerical simulation analysis for heavy lathe tool intensity static. The force of cutting tool and distributed rule of definite cutting tool internal stress strain could be precisely got by using FEM, thus the analysis results could improve cutting tool stress condition and the structural design provides the theory basis

Firstly, with studying three typical aspects as cutting force, cutting temperature and chip breaking behavior, contrast experiments of machinability were made on hydrogenated cylindrical shell materials (2.25Cr-1Mo-0.25V), 45 steel, and stainless steel (1Cr18Ni9Ti). The experiment results show that the depth of cut ap have a larger effect on the main cutting force FZ and the cutting temperature θ than the affection of the feedrate f, for that reason, in order to reduce the main cutting force FZ and the cutting temperature θ, large feedrate situation will be better for machining work of hydrogenated cylindrical shell materials. When cutting hydrogenated cylindrical shell materials , many difficult points appearance, such as large cutting force, high cutting temperature, serious chips winding, chips difficult to break etc, which has worse machinability even than stainless steel(1Cr18Ni9Ti).

PCBN cutting tools is in high speed, high temperature and high pressure environment when high speed precision hard cutting hardened steel. Shear extrusion and slip effect in high speed cutting, cutting tools wear mechanisms are different from common cutting, even cutting tools wear mechanisms in high speed is in research stage at present. In this paper, coated PCBN cutting tools wear mechanisms in high speed cutting(v＝200~600m/min) GCr15 (HRC62-64) is studied, it is helpful to obtain cutting tools structure design, cutting parameters and improve cutting tools use efficiency.

The generation procedure of saw tooth chip when PCBN tools orthogonal cutting hard steel GCr15 is emulated by FEM software ABAQUS in this study. The model effectively overcomes serious element distortions and cell singularity in high strain domain caused by large material deformation. The effects of cutting edge preparation on cutting force, cutting temperature and residual stress are analyzed. Results of FEM show that cutting edge preparation has a great impact on cutting procedure. Under the same cutting condition, cutting force, temperature and residual stress of sharp edge, honed edge and chamfered edge increases in turn, and three kinds of cutting edge have the same change rule in residual stress. Chamfered edge has a good temperature distributing, and it is the best edge preparation in hard cutting.

In the cutting process, cutting force is one of the important physical parameters, which affects the generation of cutting heat, tool life and surface precision of workpiece directly. In this paper an orthogonal design of experiment and subsequent data is analyzed using high speed finish hard cutting GCr15 whose hardness is 65HRC. Cutting speed is 200-400m/min, to study the influence of cutting parameters on cutting force, cutting force empirical model has obtained from least square method.

PCBN cutting tool’s wear in high speed precision reaches tool wear criterion will cause cutting force and cutting temperature increase clearly, chip color change or melt. Even vibration in cutting will influence dimension accuracy and surface quality of workpiece. It is very useful to establish model by FEM simulation of tool wear predicted. The influence of tool wear in cutting conditions will assurance of machining quality and efficiency, decreasing rate of product cost. PCBN cutting tool’s wear is simulated by FEM software Deform 2D, rake face wear state can be analysed by the influence of tools geometric parameters and cutting parameters tool wear.

Based on experimental results, a predictive model with certain constraints of cutting parameters (feed rate and depth of cut) and nose radius for cutting forces is solved in precision turning 3J33 alloy. The proposed model is adequate with F-ratio test and multiple correlation coefficient of it. Regression analysis shows that depth of cut and feed rate influence the principal cutting force significantly. The goal of this study is to predict cutting forces under certain constraints of cutting parameters and nose radius.

A 3D model is established in this paper to simulate cutting process of PCBN tool cylindrical cutting hardened steel GCr15 using ABAQUS/Explicit. The model effectively overcomes serious element distortions and cell singularity in high strain domain caused by material large deformation by adopting shear failure criteria and element deletion criteria. In this study cutting force, cutting temperature, surface residual stress field as well as side flow are forecasted of hard cutting process with chamfering tool preparation. It shows that satisfactory results could be obtained by FEM. The simulation results provide theoretical basis for studying hard cutting mechanism and selecting the best cutting condition in practical.

The finite element modeling and experimental validation of three-dimensional precision cutting of 3J33 maraging are presented. The commercial software MARC applied for the finite element modeling is studied the effect of tool nose radii considering tool edge radius on the principal cutting forces and the temperature fields. The model employs an updated Lagrangian formulation. The friction between the tool and the chip is assumed to follow a modified Coulomb friction law and the adaptive remeshing technique is using for the formation of chip. The tool edge radius significantly affects the cutting forces and the maximum temperature of the chip. The simulation results for tool with nose radius considering tool edge radius are compared with experimentally measured data and found to be in good agreement.

Objectives Inflammation and platelet aggregation and activation are key processes in the initiation of a cardiovascular event. Patients with metabolic syndrome have a high risk of cardiovascular events. This study determined whether small and medium doses of aspirin have anti-inflammation and antiplatelet aggregation effects in patients with metabolic syndrome. Methods One hundred and twenty-one consecutive patients with metabolic syndrome were randomized into three groups, receiving 100 mg/day of aspirin, 300 mg/day of aspirin or a placebo, respectively, for 2 weeks. The blood levels of thromboxane B2 (TXB2), a stable product of the platelet aggregation mediator TXA2, 6-keto-prostaglandin F1-α (6-keto-PGF1-α), a stable product of the endogenous cyclooxygenase metabolite prostaglandin I2, and inflammatory mediators including high-sensitivity C-reactive protein (hs-CRP), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were determined by ELISA and radioimmunoassay. Key findings The blood levels of hs-CRP, TNF-α, IL-6 and TXB2 were significantly decreased after 2 weeks of treatment with 300 mg/day of aspirin. Patients who received 100 mg/day of aspirin had decreased blood levels of hs-CRP and TXB2. The blood level of IL-6 in the 300 mg/day aspirin group was significantly lower than that in the other two groups after 2 weeks of therapy. Aspirin at either dose did not affect the blood level of 6-keto-PGF1-α. Conclusions Aspirin at all doses suppresses the blood levels of inflammatory markers and the platelet aggregation mediator TXA2 in Chinese patients with metabolic syndrome. Since the suppression induced by 300 mg/day of aspirin was greater than that induced by 100 mg/day of aspirin, these data suggest that 300 mg/day of aspirin may be beneficial in decreasing the risk of cardiovascular events in Chinese patients with metabolic syndrome.

Statins ameliorate myocardial fibrosis after myocardial infarction. We designed this study to determine whether fluvastatin reduced hypertension-induced myocardial hypertrophy and fibrosis and whether these fluvastatin effects involved transforming growth factor beta1 (TGF-beta1) and Smad 7, factors known to play a role in the myocardial hypertrophy and fibrosis. We randomized 14 week old spontaneously hypertensive rats (SHRs) to receiving vehicle or 5-20 mg/kg/day fluvastatin for 8 weeks. Wistar Kyoto (WKY) rats receiving vehicle or 10 mg/kg/day fluvastatin were also studied. SHRs had an increased blood pressure, left ventricular hypertrophy and fibrosis compared with WKY rats. SHRs also had an elevated TGF-beta1 expression and a decreased Smad 7 expression. These changes in SHRs were dose-dependently attenuated by fluvastatin. For example, the hydroxyproline content was 3.2+/-0.1, 4.0+/-0.1 and 3.5+/-0.1 microg/mg heart and the Smad 7 protein expression was 5.1+/-0.6, 1.0+/-0.1 and 4.1+/-0.7 arbitrary units for WKY rats, SHRs and SHRs receiving 20 mg/kg/day fluvastatin, respectively. The hydroxyproline content in the SHRs treated with or without fluvastatin was positively correlated with the left ventricular mass index, systolic blood pressure and the amount of TGF-beta1 proteins and negatively correlated with the Smad 7 expression level. The left ventricular mass index was positively correlated with the systolic blood pressure. Fluvastatin did not alter the blood pressure, left ventricular mass index and collagen content of WKY rats. These results suggest that fluvastatin reduces hypertension-induced myocardial hypertrophy and fibrosis. These effects may involve an increased expression of Smad 7 and a decreased expression of TFG-beta1. Our results call for clinical studies to evaluate these fluvastatin effects in hypertensive patients.

To explore the effects of ischemic postconditioning on ischemia/reperfusion injury in isolated hypertrophied rat heart and investigate the signal transduction pathway changes induced by ischemia postconditioning.Cardiac hypertrophy was induced in rats by abdominal aortic banding, and isolated hypertrophied rat heart ischemia/reperfusion model was made by Langendorff technique to evaluate the effects of ischemia postconditioning on left ventricular systole pressure, coronary artery flow, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) release, myocardial infarction size, and the level of myocardial phospho-protein kinase B/Akt (Ser473), phospho-glycogen synthase kinase-3beta (Ser9). Following groups were studied (n = 12 each group): IR, 30 min ischemia (I)/60 min Reperfusion (R); Post: 30 min ischemia, 6 circles of 10 s I/10 s R followed by 60 min R; Post Wort: 30 min ischemia, 6 circles of 10 s I/10 s R, wortmannin (10(-7) mol/L) followed by 60 min R; Wort: 30 min ischemia, wortmannin (10(-7) mol/L) followed by 60 min R.Left ventricular systolic pressure and coronary artery flow were significantly increased, myocardial infarction size and the release of CPK, LDH significantly reduced in Post group compared to that in IR group. Phospho-protein kinase B/Akt (Ser473) and phospho-glycogen synthase kinase-3beta (Ser9) levels were also significantly higher in Post group than that in IR group. Phosphatidylinositol 3-kinase (PI3K) inhibitor wortmannin prevented the increase of phospho-protein kinase B/Akt (Ser473) and phospho-glycogen synthase kinase-3beta (Ser9) induced by ischemic postconditioning, but only partly abolished the cardioprotection of ischemic postconditioning.Ischemic postconditioning attenuates ischemia/reperfusion injury in isolated hypertrophied rat heart. The cardioprotective effects of ischemic postconditioning were partly mediated through PI3K/Akt/GSK-3beta signaling pathway.