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Contamination events in water distribution networks (WDN) pose significant threats to water supply and public health. Rapid and accurate contamination source identification (CSI) can facilitate the development of remedial measures to reduce impacts. Though many machine learning (ML) methods have been proposed for fast detection, there is a critical need for approaches capturing complex spatial dynamics in WDNs to enhance prediction accuracy. This study proposes a gated graph neural network (GGNN) for CSI in the WDN, incorporating both spatiotemporal water quality data and flow directionality between network nodes. Evaluated across various contamination scenarios, the GGNN demonstrates high prediction accuracy even with limited sensor coverage. Notably, directional connections significantly enhance the GGNN CSI accuracy, underscoring the importance of network topology and flow dynamics in ML-based WDN CSI approaches. Specifically, the method achieves a 92.27% accuracy in narrowing the contamination source to 5 points using just 2 h of sensor data. The GGNN showcases resilience under model and measurement uncertainties, reaffirming its potential for real-time implementation in practice. Moreover, our findings highlight the impact of sensor sampling frequency and measurement accuracy on CSI accuracy, offering practical insights for ML methods in water network applications. • A gated graph neural network is proposed for contamination source identification. • The new model utilizes network topology and flow directions for enhanced performance. • Improved sensor sampling frequency and measurement accuracy boost model performance. • Model exhibits resilience to demand and measurement uncertainties. [ABSTRACT FROM AUTHOR]

Abstract Epidemiological studies have revealed positive correlation between particulate matter with an aerodynamic diameter of < 2.5 µm (PM 2.5) and pulmonary fibrosis (PF). As etiology and pathogenesis of PF have not been fully elucidated, this study was to investigate the potential mechanism by which PM 2.5 exposure adversely induced PF in vivo and in vitro. In the present study, 6-week-old C57/BL6J mice were intranasally administrated with PM 2.5 (100 μg/day) for 4 weeks. Micro-CT and hematoxylin-eosin (HE) staining analysis showed that lung inflammation and incipient fibrosis symptoms were induced after PM 2.5 exposure. The expression of Transforming growth factor-β1 (TGF-β1), α-Smooth muscle actin (α-SMA), and Collagen type I (COL1) in mice lung was increased. Upregulation of TGF-β1 in mice serum was also detected by ELISA after exposure to PM 2.5. Moreover, chronic PM 2.5 exposure on human bronchial epithelial cell line BEAS-2B cells led to activation of TGF-β1/SMAD3 pathway, TGF-β1 excretion and epithelial-mesenchymal transition (EMT), while PM 2.5 also triggered the activation of TGF-β1/SMAD3 pathway, TGF-β1 excretion as well as differentiation of human pulmonary fibroblast cell line HFL-1 cells, and TGF-β1 production in mouse macrophage cell line RAW264.7 cells. Furthermore, cell culture medium of PM 2.5 -treated BEAS-2B and RAW264.7 cells could both activate TGF-β1/SMAD3 signaling, α-SMA and COL1 upregulation in HFL-1 cells. Therefore, we concluded that PM 2.5 could induce PF by targeting pulmonary epithelium, macrophages and fibroblasts, suggesting that PM 2.5 was a potent initiator of PF. Graphical abstract fx1 Highlights • PM 2.5 induced lung inflammation and fibrosis in mice. • PM 2.5 exposure induced profibrotic EMT in lung epithelial cells. • PM 2.5 directly promoted differentiation of pulmonary fibroblasts. • PM 2.5 induced pulmonary fibroblasts differentiation via lung epithelium/macrophages. [ABSTRACT FROM AUTHOR]

• Simulation ability of dynamic response to the complete AMB-rotor drop process;. • Theoretical analysis of dry whirl and dry whip of a vertical rotor;. • Simulation model and test rig together verify the theoretical validity;. • Parametric study of the factors influencing the natural whirl speed. A horizontal rotor is usually the research subject of rotor drop failure in active magnetic bearing (AMB) test rigs. However, research shows, that a vertical rotor drop failure is not sufficiently understood at present. The experiments in other research studies show that the vertical rotor dynamic response is not simple whirl behavior after dropping on the touchdown bearing (TDB), which concludes dry whirl and dry whip processes, where the former is synchronous forward whirl, and the latter is subsynchronous forward whirl. To predict the dynamic response of a vertical rotor drop failure, theoretical research based on a rotor-TDB model system is developed in this paper, and the effectiveness of this model is validated by an AMB-TDB rotor experiment. The conclusion is that the natural whirl speed and the resulting critical speed clearly distinguish two states of forward whirl motion. When the rotation speed is less than the critical speed, the rotor is in a dry whirl state; otherwise, it behaves as in a dry whip. The rotor unbalance is introduced in the model, which explains the change in the whirl speed. Moreover, the influencing factors on the natural whirl speed are analyzed in depth. The result shows that parameters of the TDB, such as the friction coefficient and protective clearance, and the rotor unbalance have significant effects. [ABSTRACT FROM AUTHOR]

• Studied instability of 3 models of friction-induced vibration due to mode-coupling. • Discovered the intriguing and counter-intuitive roles of damping on stability. • Revealed drop of stability boundary caused by nonproportional damping. • Analysed damping effects in one direction or a part of the system on stability. • Found unsual and beneficial effects of proportional damping. This study addresses a fundamental problem of linear friction-induced vibration (FiV), the intriguing role of damping on the instability of FiV in the form of mode-coupling. Two well-known classic 2-degree-of-freedom (DoF) slider-belt models are revisited, and a 4-DoF slider-belt model considering different damping configurations in the slider and the belt is investigated. Since proportional damping is very rare in reality, non-proportional damping is given much attention in this paper. Firstly, the analytical solutions of bifurcation boundary of the critical coefficients of friction of the classic 2-DoF models are derived, which show the subtle role of damping clearly and theoretically explain and clear misunderstandings and confusions on the phenomenon about the drop of the stability boundary from that of the undamped system caused by adding non-proportional damping. Secondly, a further increase of non-proportional damping is found to improve the stability and even bring higher degree of stability than increasing proportional damping (which is a new finding). Thirdly, the influences of the different damping distributions among the system components on the stability of the 4-DoF slider-belt model are explored. The evolution of the bifurcation boundary indicates the importance of the ratio of the horizontal to the vertical damping in the slider and in the belt. For some non-proportional damping values, the bifurcation boundary fluctuates, which could exhibit local optimal values of the ratio of damping in different directions of a system component and can be exploited in design against FiV. These findings are valid for general linear second-order dynamic systems with an asymmetric stiffness matrix. [ABSTRACT FROM AUTHOR]

• The relationship between TLR2 polymorphism and TB susceptibility is not as close as we thought before. • Screening more gene mutations to provide new ideas for prevention and treatment of TB. • TLR2 rs5743708 polymorphism exhibits a significant association with a higher tuberculosis risk. • The polymorphism of TLR2 gene was systematically reviewed for the first time. Toll-like receptor 2 (TLR2) is a crucial factor in the development of tuberculosis. However, no studies have explored the association between TLR2 polymorphisms and tuberculosis susceptibility. This study aimed to explore the correlation between tuberculosis susceptibility and TLR2 polymorphisms (rs3804099, rs3804100, rs1898830, rs5743708, rs121917864, and (-196-174) del). All relevant online databases including PubMed, CNKI, WANFANG DATA, and METSTR-FMRS were systematically searched. STATA17.0 (Stata Corp LP, College Station, Texas, USA) was used. A total of 37 studies, covering six polymorphisms and comprising 9,474 cases and 10,295 controls, were included in this analysis. rs3804099(C vs T: OR = 1.00, 95 % CI: 0.93–1.08, CC + TC vs TT: OR = 1.04, 95 % CI: 0.98–1.10), rs3804100 (C vs T: OR = 1.19, 95 % CI: 0.93–1.07, CC + TC vs TT: OR = 0.97, 95 % CI: 0.89–1.06), rs1898830(G vs A: OR = 0.90, 95 % CI: 0.81–1.00, GG + AG vs AA: OR = 0.87, 95 % CI: 0.67–1.12), (-196 ∼174) del polymorphism (Del vs Ins: OR = 0.93,95 % CI: 0.76–1.14, DD + DI vs II: OR = 0.92,95 % CI: 0.72–1.17). This study indicated that only the TLR2 rs5743708 polymorphism exhibited a significant association with a higher tuberculosis risk, while TLR2 rs3804099, rs3804100, rs1898830, rs121917864, and (-196-174) del polymorphisms were not associated with tuberculosis susceptibility. [ABSTRACT FROM AUTHOR]