Single chamber permanent epicardial pacing for children with congenital heart disease after surgical repair

BACKGROUND: To analyze the 10-year experience of single chamber permanent epicardial pacemaker placement for children with congenital heart diseases (CHD) after surgical repair. METHODS: Between 2002 and 2014, a total of 35 patients with CHD (age: 26.9 ± 23.2 months, weight: 9.7 ± 5.6 kg) received permanent epicardial pacemaker placement following corrective surgery. Echocardiography and programming information of the pacemaker, as well as major adverse cardiac events (MACE) as heart failure or sudden death, were recorded during follow-up (46.8 ± 33.8 months). RESULTS: Acute ventricular stimulation threshold was 1.34 ± 0.72 V and no significant increase was observed at the last follow-up as 1.37 ± 0.81 V (p = 0.93). Compared with initial pacemaker implantation, the last follow-up didn’t show significant increases in impedance (p = 0.327) or R wave (p = 0.635). Four patients received pacemaker replacement because of battery depletion. 7/35 (20 %) of patients experienced MACE. Although the age and body weight were similar between patients with and without MACE, the patients with MACE were with complex CHD (100 % vs.55.6 %, p = 0.04). CONCLUSION: High-degree iatrogenic atrioventricular block was the primary reason for placement of epicardial pacemaker for patients with CHD after surgical repair. Pacemaker placement with the steroid-eluting leads results in acceptable outcomes, however, the pacemaker type should be optimized for the children with complex CHD

Few-Shot Bioacoustic Event Detection with Frame-Level Embedding Learning System

This technical report presents our frame-level embedding learning system for the DCASE2024 challenge for few-shot bioacoustic event detection (Task 5).In this work, we used log-mel and PCEN for feature extraction of the input audio, Netmamba Encoder as the information interaction network, and adopted data augmentation strategies to improve the generalizability of the trained model as well as multiple post-processing methods. Our final system achieved an F-measure score of 56.4%, securing the 2nd rank in the few-shot bioacoustic event detection category of the Detection and Classification of Acoustic Scenes and Events Challenge 2024

Vibration Frequency Characteristic Study of Two-stage Excitation Valve Used in Vibration Experiment System

To satisfy the demands of higher frequency and amplitude in hydraulic vibration experiment system, the two-stage excitation valve is presented, and a mathematical model of two-stage excitation valve is established after analyzing the working principle of two-stage excitation valve, then the influence of relevant parameters on the displacement of main spool of two-stage excitation valve is studied by using Matlab/Simulink to calculate and analyze. The results show that the displacement of main spool will be smaller with bigger diameter and more secondary valve ports. When the reversing frequency is higher and the oil supply pressure is lower as well as the axial guide width of valve ports is smaller, the maximum displacement of main spool is smaller. The new two-stage excitation valve is easy to adjust reversing frequency and flow. The high frequency can be achieved by improving the rotation speed of servo motor and adding the number of secondary valve ports; the large flow can be realized by increasing the axial guide width of secondary valve ports and oil supply pressure. The result of this study is of guiding significance for designing the rotary valve for the achievement of higher reversing frequency and larger flow

Pioglitazone alleviates oxygen and glucose deprivation-induced injury by up-regulation of miR-454 in H9c2 cells

Objective(s): Pioglitazone, an anti-diabetic agent, has been widely used to treat type II diabetes. However, the effect of pioglitazone on myocardial ischemia reperfusion injury (MIRI) is still unclear. Herein, the objective of this study is to learn about the regulation and mechanism of pioglitazone effects on oxygen glucose deprivation (OGD)-induced myocardial cell injury.Materials and Methods: A cellular injury model of OGD-treated H9c2 cells in vitro was constructed to simulate ischemic/reperfusion (I/R) injury. Then, various concentrations of pioglitazone (0, 2.5, 5, 7.5 and 10 μM) were used for the treatment of H9c2 cells, and CCK-8, flow cytometry and western blot assays were performed to examine cell viability, apoptosis, and the protein levels of factors involved in cell cycle and apoptosis in OGD-treated cells. MiR-454 inhibitor was used to suppress miR-454 expression, and whether miR-454 was involved in regulating OGD-induced cell injury was studied. Two key signal pathways were examined to uncover the underlying mechanism. Results: OGD reduced cell proliferation and induced apoptosis in H9c2 cells (

Research on seed node mining algorithm in large-scale temporal graph

Most of the existing maximizing influence algorithms based on temporal graph were not applicable for large-scale networks due to the low time efficiency or narrow influence range.Therefore, the seed node mining algorithm named CHG combining heuristic algorithm and greedy strategy was proposed.Firstly, based on the time sequence characteristics of information diffusion in temporal graph, the concept of two-order degree of nodes was given, and the influence of nodes was heuristically evaluated.Secondly, the nodes were filtered according to the influence evaluation results, and the candidate seed node set was constructed.Finally, the marginal effect of candidate seed nodes was calculated to solve the overlap of influence ranges between nodes to ensure the optimal combination of seed nodes.The experiments were carried out on three different scale data sets, and the results show that the proposed algorithm can ensure the high influence of the seed node set even though its running time is relatively shorter.And it can achieve a better trade-off between the time efficiency and the influence range of the seed node set

Physiological and ecological responses of flue-cured tobacco to field chilling stress: insights from metabolomics and proteomics

IntroductionCurrently, research on tobacco's response to chilling stress is mostly limited to laboratory simulations, where temperature is controlled to study physiological and molecular responses. However, laboratory conditions cannot fully replicate the complex environment of field chilling stress, so conducting research under field conditions is crucial for understanding the multi-level adaptive mechanisms of tobacco to chilling stress in natural environments.MethodsThis study aims to use field trials, starting from physiological responses, combined with proteomics and untargeted metabolomics, to systematically reveal the physiological and biochemical characteristics and key molecular mechanisms of tobacco leaves under chilling stress. It provides new insights into tobacco's adaptation strategies under chilling stress.ResultsThe results showed that (1) chilling stress damages the appearance of tobacco leaves, reduces the chlorophyll content, increases H2O2 and malondialdehyde (MDA) levels in cold-injured tobacco leaves, and damages the plasma membrane system. Although catalase (CAT) activity increases to cope with the accumulation of reactive oxygen species (ROS), the activities of key antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD) significantly decrease, indicating that the antioxidant system of tobacco leaves fails in environments with sudden temperature drops. (2) Proteomics analysis indicated that 410 differentially expressed proteins were identified in cold-stressed tobacco leaves, with 176 upregulated and 234 downregulated. Tobacco leaves under chilling stress attempt to maintain energy supply and physiological stability by enhancing glycolysis, starch, and sucrose metabolism pathways. Concurrently, chilling stress triggers the expression of proteins related to cell wall reinforcement and antioxidant defense. However, due to impaired ribosomal function, protein synthesis is significantly inhibited, which aggravates damage to photosynthesis and cellular functions. (3) Metabolomics analysis revealed that the differential metabolites in cold-stressed tobacco leaves were mainly enriched in tyrosine metabolism, isoquinoline alkaloid biosynthesis, and fatty acid degradation pathways. This indicates that under chilling stress, tobacco leaves enhance adaptability by regulating energy metabolism, increasing antioxidant capacity, and stabilizing cell membrane structure.ConclusionsTherefore, under chilling stress, tobacco leaves exhibit complex physiological adaptability through multiple regulatory mechanisms involving proteins and metabolites. The research results provide important insights into the metabolic regulatory mechanisms of tobacco in response to extreme environments and also enhance the theoretical foundation for addressing low-temperature stress in practical production

Multi-nanoprecipitate strengthened aluminium-scandium alloy for additive manufacturing

Aluminium alloys, celebrated for their high strength-to-weight ratio and remarkable tensile strength in lightweight structural applications, are integral to a broad spectrum of industries. In this work, we proposed a precipitation strengthening model incorporating the competitive relationship between nucleation and growth to optimise composition, and developed an age-hardenable Al-4.2Mg-0.7Mn-1.1Sc-0.5Zr-0.6Cu-0.1Zn-0.1Fe (wt.%) alloy for laser powder bed fusion. This alloy features a hierarchically heterogeneous microstructure with a trimodal grain and nanoprecipitate distribution. It undergoes the nucleation and growth of secondary Al3X precipitates and the subsequent dissolution of the S-phase, with a significant number of T-phase observed by atom probe tomography. This combined multi-precipitate structure results in a maximum yield strength of 650 MPa displaying a high work hardening rate, making it a promising candidate for complex-shaped, high-strength and ductile components in advanced light-weight structural engineering applications. The new modelling approach to control nanoprecipitation nucleation and growth aids in realising the potential for near-net shape forming of Al alloy components