Irradiation-induced telomerase activity and gastric cancer risk: a case-control analysis in a Chinese Han population

<p>Abstract</p> <p>Background</p> <p>Telomerase expression is one of the characteristics of gastric cancer (GC) cells and telomerase activity is frequently up-regulated by a variety of mechanisms during GC development. Therefore, we hypothesized that elevated levels of activated telomerase might enhance GC risk due to increased propagation of cells with DNA damage, such as induced by γ-radiation.</p> <p>Methods</p> <p>To explore this hypothesis, 246 GC cases and 246 matched controls were recruited in our case-control study. TRAP-ELISA was used to assess the levels of telomerase activity at baseline and after γ-radiation and the γ-radiation-induced telomerase activity (defined as after γ-irradiation/baseline) in cultured peripheral blood lymphocytes (PBLs).</p> <p>Results</p> <p>Our data showed that there was no significant difference for the baseline telomerase activity between GC cases and controls (10.17 ± 7.21 <it>vs. </it>11.02 ± 8.03, <it>p </it>= 0.168). However, after γ-radiation treatment, γ-radiation-induced telomerase activity was significantly higher in the cases than in the controls (1.51 ± 0.93 <it>vs</it>. 1.22 ± 0.66, <it>p </it>< 0.001). Using the median value of γ-radiation-induced telomerase activity in the controls as a cutoff point, we observed that high γ-radiation-induced telomerase activity was associated with a significantly increased GC risk (adjusted odds ratio, 2.45; 95% confidence interval, 1.83-3.18). Moreover, a dose response association was noted between γ-radiation-induced telomerase activity and GC risk. Age, but not sex, smoking and drinking status seem to have a modulating effect on the γ-radiation-induced telomerase activities in both cases and controls.</p> <p>Conclusion</p> <p>Overall, our findings for the first time suggest that the increased γ-radiation-induced telomerase activity in PBLs might be associated with elevated GC risk. Further confirmation of this association using a prospective study design is warranted.</p

Modeling and H∞ Control of Active-Passive Vibration Isolation for Floating Raft System

This paper presents a new approach for constructing a mathematical model of the floating raft system directly from input-output measurements in the presence of noise. In contrast to the original OKID/ERA algorithm, which works through the observer Markov parameters, the new approach used observer output residuals to convert the initial stochastic identification to a virtually deterministic identification problem. The extension of deterministic algorithm to stochastic problems by proposed stochastic-to-deterministic conversion can be done with ease. A MIMO (multiple-input multiple-output) system state-space model and an associated Kalman filter gain can be identified. H∞ controller with high robustness to model error is designed to solve multifrequency varying vibration for floating raft system. Both simulated and experimental results confirm the validity and the benefits of the approach

Fault Detection in Active Magnetic Bearings Using Digital Twin Technology

Active magnetic bearings (AMBs) are widely used in different industries to offer non-contact and high-velocity rotational support. The AMB is prone to failures, which may result in system instability and decreased performance. The efficacy and reliability of magnetic bearings can be significantly affected by failures in the sensor and control systems, leading to system imbalance and possible damage. A digital twin is an advanced technology that has been increasingly used in different industrial fields. It allows for the creation and real-time monitoring of virtual replicas of physical systems. This paper proposes a novel method for fault detection of Active Magnetic Bearings (AMBs) using digital twin technology and a neural network. The digital twin model serves as a virtual representation that accurately replicates the actual AMB system’s efficiency and features, allowing continuous real-time monitoring and detection of faults. The conventional neural network (CNN) is used as the primary tool for identifying faults in the Active Magnetic Bearing (AMB) within a digital twin model. Experiments proved the effectiveness and robustness of the suggested approach method to fault detection in the AMB

Critical Vibration and Control of the Maglev High-Speed Motor Based on &mu;&ndash;Synthesis Control

The Maglev motor has the characteristics of high-speed and high-power density, and is widely used in compressors, molecular pumps and other high-speed rotating machinery. With the requirements of miniaturization and high speed of rotating machinery, the rotor of the maglev motor will operate above the bending critical speed, and the critical vibration control of the flexible rotor is facing challenges. In order to solve the problem of the critical vibration suppression of the maglev high-speed motor, the system model of the maglev motor is established, the rotordynamics of the flexible rotor are analyzed and the rotor model is modal truncated to reduce the order. Then, the &mu;&ndash;controller is designed, and the weighting functions are designed to deal with the modal uncertainty. Finally, an experimental platform of the maglev motor with the flexible rotor is built to verify the effect of the &mu;&ndash;control on the suppression of the critical vibration of the maglev rotor

Dynamic analysis and vibration testing of CFRP drive-line system used in heavy-duty machine tool

Low critical rotary speed and large vibration in the metal drive-line system of heavy-duty machine tool affect the machining precision seriously. Replacing metal drive-line with the CFRP drive-line can effectively solve this problem. Based on the composite laminated theory and the transfer matrix method (TMM), this paper puts forward a modified TMM to analyze dynamic characteristics of CFRP drive-line system. With this modified TMM, the CFRP drive-line of a heavy vertical miller is analyzed. And the finite element modal analysis model of the shafting is established. The results of the modified TMM and finite element analysis (FEA) show that the modified TMM can effectively predict the critical rotary speed of CFRP drive-line. And the critical rotary speed of CFRP drive-line is 20% higher than that of the original metal drive-line. Then, the vibration of the CFRP and the metal drive-line were tested. The test results show that application of the CFRP drive shaft in the drive-line can effectively reduce the vibration of the heavy-duty machine tool. Keywords: CFRP drive-line system, Dynamic behavior, Transfer matrix, Vibration measuremen

Research on torsional capacity of composite drive shaft under clockwise and counter-clockwise torque

The design of lay-up has a great influence on the mechanical properties of carbon fiber–reinforced plastic drive shaft. In this research, the stress states of each layer in the carbon fiber–reinforced plastic drive shaft were studied, which were different under opposite torque directions. The Tsai–Wu criterion was used to judge the torsional stability of the composite laminates. The data from finite element analysis showed that torsional capacities of a stacking sequence vary greatly with torque direction, and reasonable lay-up design can reduce the difference. Torque direction should not be ignored when designing a carbon fiber–reinforced plastic drive shaft

Evaluation of Switching Power Amplifier Topology for Active Magnetic Bearings

Active magnetic bearings (AMBs) have led to great progress in the field of rotating machinery due to their many advantages, such as their non-contact and non-lubrication properties. As the key component of an AMB actuator, the switching power amplifier has an important impact on the performance of magnetic bearings and rotating machinery. In this paper, the topologies of switching power amplifiers for AMBs are introduced. The traditional half-bridge topology and two newly proposed topologies—the three-phase-half-bridge and neutralized-sharing-bridge topology—are analyzed and discussed. The volume, current output performance and cost of the power amplifier with different topologies are comprehensively evaluated, providing a theoretical basis and guidance for the selection and design of the topology of switching power amplifiers for AMBs under different conditions

CFD-Based Flow Channel Optimization and Performance Prediction for a Conical Axial Maglev Blood Pump

Ventricular assist devices or total artificial hearts can be used to save patients with heart failure when there are no donors available for heart transplantation. Blood pumps are integral parts of such devices, but traditional axial flow blood pumps have several shortcomings. In particular, they cause hemolysis and thrombosis due to the mechanical contact and wear of the bearings, and they cause blood stagnation due to the separation of the front and rear guide wheel hubs and the impeller hub. By contrast, the implantable axial flow, maglev blood pump has the characteristics of no mechanical contact, no lubrication, low temperature rise, low hemolysis, and less thrombosis. Extensive studies of axial flow, maglev blood pumps have shown that these pumps can function in laminar flow, transitional flow, and turbulent flow, and the working state and performance of such pumps are determined by their support mechanisms and flow channel. Computational fluid dynamics (CFD) is an effective tool for understanding the physical and mechanical characteristics of the blood pump by accurately and effectively revealing the internal flow field, pressure–flow curve, and shear force distribution of the blood pump. In this study, magnetic levitation supports were used to reduce damages to the blood and increase the service life of the blood pump, and a conical impeller hub was used to reduce the speed, volume, and power consumption of the blood pump, thereby facilitating implantation. CFD numerical simulation was then carried out to optimize the structural parameters of the conical axial maglev blood pump, predict the hemolysis performance of the blood pump, and match the flow channel and impeller structure. An extracorporeal circulation simulation platform was designed to test whether the hydraulic characteristics of the blood pump met the physiological requirements. The results showed that the total pressure distribution in the blood pump was reasonable after optimization, with a uniform pressure gradient, and the hemolysis performance was improved

A liquid phosphorus-containing imidazole derivative as flame-retardant curing agent for epoxy resin with enhanced thermal latency, mechanical, and flame-retardant performances

The development of phosphorus-containing flame retardants combining good compatibility with matrix, low curing temperature, and mechanically reinforcing effect has remained a major challenge. Herein, we reported the synthesis of a liquid flame-retardant curing agent (DA) via the nucleophilic substitution between diphenylphosphinic chloride and 1-(3-aminopropyl)-imidazole (AI). DA exhibited good blending and latency towards epoxy resin (EP) at room temperature. According to DSC studies, DA could rapidly cure EP at moderate temperature. Compared with EP/AI sample, EP/DA samples displayed comparable or higher glass transition temperature (Tg) and enhanced mechanical properties due to the introduction of rigid diphenylphosphinyl group and improved cross-linking density. Moreover, DA improved the flame-retardant performances of EP thermoset. For instance, the LOI and UL94 rating of EP/DA-16 sample achieved 37.2 % and V-0, respectively. In addition, the peak of heat release rate (PHRR), average of heat release rate (AHRR), fire growth rate (FIGRA), and total heat release (THR) for EP/DA-16 sample reduced by 32 %, 42 %, 28 % and 27 % in comparison to EP/AI sample, respectively. DA was characterized by its good compatibility with EP, moderate curing temperature, fast curing rate, suitable thermal latency, mechanical reinforcing and flame-retardant effects, and thus it had a broad application prospect in various industrial fields

A Liquid Phosphaphenanthrene-Derived Imidazole for Improved Flame Retardancy and Smoke Suppression of Epoxy Resin

The fabrication of high-performance thermosetting polymers with intrinsic flame retardancy and smoke suppression is necessary but challenging. Herein, we have successfully synthesized a liquid phosphaphenanthrene/imidazole-containing curing agent (DOPO-AI) for epoxy resin (EP) by the Atherton-Todd reaction of 1-(3-Aminopropyl)imidazole (AI) and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). The as-prepared EP/DOPO-AI samples exhibit comparable mechanical properties to the reference EP/AI-6 sample, with slightly decreased glass transition temperatures. Impressively, the EP/DOPO-AI sample can pass the UL-94 V-0 rating and achieve a limited oxygen index (LOI) value of 37.0%. Additionally, the EP/DOPO-AI sample shows 26.3%, 36.6%, and 24.4% reductions in the total heat release (THR), peak of heat release rate (pHRR), and total smoke production (TSP) relative to the EP/AI-6 sample, indicating a significantly reduced fire hazard. The significant enhancements in flame retardancy and smoke suppression are attributed to the condensed-and gaseous-phase effects of DOPO-AI. This work demonstrates a feasible methodology for creating high-performance EPs with inherent flame retardancy and smoke suppression, holding great promise in the future