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Abstract Aiming at the problem that the geomagnetic sensor is vulnerable to external interference in the navigation process, this paper analyzes the frequency distribution range of geomagnetic signal and the noise characteristics in geomagnetic signal and proposes an improved morphological filtering and Hilbert–Huang transform (IMMF–IHHT) algorithm to extract and recognize the features of geomagnetic measurement signal. To avoid frequency aliasing and distortion caused by empirical mode decomposition, an improved morphological filtering algorithm based on mean constraint is used to preprocess the measured signal. The Hilbert spectrum of the decomposed signal is solved, the signal components are discriminated by the similarity criterion, and the signal components in line with the frequency range of the geomagnetic signal are extracted and processed to reconstruct the geomagnetic measurement signal. Simulation and experiments show that the signal-to-noise ratio and root-mean-square error of IMMF–IHHT combination algorithm are better than MF-HHT combination algorithm and IHHT algorithm. This algorithm has good signal feature extraction and recognition ability.

Bone cancer pain (BCP) is a common pathologic pain associated with destruction of bone and pathological reconstruction of nervous system. Current treatment strategies in clinical is inadequate and have unacceptable side effects due to the unclear pathology mechanism. In the present study, we showed that transplantation of Walker 256 cells aggravated mechanical allodynia of BCP rats (**p < 0.01 vs. Sham), and the expression of ASIC3 (Acid-sensitive ion channel 3) and TRPV1 was obviously enhanced in L4-6 dorsal root ganglions (DRGs) of BCP rats (**p < 0.01 vs. Sham). ASIC3 and TRPV1 was mainly expressed in CGRP and IB4 positive neurons of L4-6 DRGs. While, TRPV1 but not ASIC3 was markedly upregulated in L4-6 spinal dorsal horn (SDH) of BCP rats (**p < 0.01 vs. Sham). Importantly, intrathecal injection of CPZ (a TRPV1 inhibitor) or Amiloride (an ASICs antagonist) markedly increased the paw withdraw threshold (PWT) of BCP rats response to Von Frey filaments (**p < 0.01 vs. BCP + NS). What’s more, intraperitoneally injection of Metformin or Vinorelbine markedly elevated the PWT of BCP rats, but reduced the expression of TRPV1 and ASIC3 in L4-6 DRGs and decreased the TRPV1 expression in SDH (*p < 0.05, **p < 0.01 vs. BCP + NS). Collectively, these results suggest an effective analgesic effect of Metformin on mechanical allodynia of BCP rats, which may be mediated by the downregulation of ASIC3 and TRPV1.

Aims: To determine whether acid-sensing ion channel 1 (ASIC1)–sodium-potassium-chloride cotransporter 1 (NKCC1) signaling pathway participates in chronic visceral pain of adult rats with neonatal maternal deprivation (NMD).Methods: Chronic visceral pain was detected by colorectal distension (CRD). Western blotting and Immunofluorescence were performed to detect the expression and location of ASIC1 and NKCC1. Whole-cell patch-clamp recordings were performed to record spinal synaptic transmission.Results: The excitatory synaptic transmission was enhanced and the inhibitory synaptic transmission was weakened in the spinal dorsal horn of NMD rats. ASIC1 and NKCC1 protein expression in the spinal dorsal horn was significantly up-regulated in NMD rats. Incubation of Amiloride reduced the amplitude of mEPSCs. Incubation of Bumetanide (BMT) increased the amplitude of mIPSCs. Intrathecal injection of ASIC1 or NKCC1 inhibitors reversed the threshold of CRD in NMD rats. Also, Amiloride treatment significantly reversed the expression of NKCC1 in the spinal dorsal horn of NMD rats.Conclusion: Our data suggest that the ASIC1-NKCC1 signaling pathway is involved in chronic visceral pain in NMD rats.

A novel H∞ filter called square-root cubature H∞ Kalman filter is proposed for attitude measurement of high-spinning aircraft. In this method, a combined measurement model of three-axis geomagnetic sensor and gyroscope is used, and the Euler angle algorithm model is used to reduce the state dimension and linearize the state equation, which can reduce the amount of calculation. Simultaneously, the method can be applied to the case of measurement noise uncertainty. By continuously modifying the error limiting parameters to update the measurement noise estimation, the filtering accuracy and robustness can be improved. The square-root forms enjoy a consistently improved numerical stability because all the resulting covariance matrices by QR decomposition are guaranteed to stay positive semidefinite. The algorithm is applied to the simulation experiment of attitude measurement with the combination of geomagnetic sensor and gyroscope and compared with the results of Unscented Kalman filter, cubature Kalman filter, square root cubature Kalman filter, and singular value decomposition cubature Kalman filter, which proves the effectiveness and superiority of the algorithm.

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by chronic abdominal pain and alteration of bowel movements. The pathogenesis of visceral hypersensitivity in IBS patients remains largely unknown. Hydrogen sulfide (H2S) is reported to play an important role in development of visceral hyperalgesia. However, the role of H2S at spinal dorsal horn level remains elusive in visceral hypersensitivity. The aim of this study is designed to investigate how H2S takes part in visceral hypersensitivity of adult rats with neonatal colonic inflammation (NCI). Visceral hypersensitivity was induced by neonatal colonic injection of diluted acetic acid. Expression of an endogenous H2S synthesizing enzyme cystathionine β-synthetase (CBS) was determined by Western blot. Excitability and synaptic transmission of neurons in the substantia gelatinosa (SG) of spinal cord was recorded by patch clamping. Here, we showed that expression of CBS in the spinal dorsal horn was significantly upregulated in NCI rats. The frequency of glutamatergic synaptic activities in SG was markedly enhanced in NCI rats when compared with control rats. Application of NaHS increased the frequency of both spontaneous and miniature excitatory post-synaptic currents of SG neurons in control rats through a presynaptic mechanism. In contrast, application of AOAA, an inhibitor of CBS, dramatically suppressed the frequency of glutamatergic synaptic activities of SG neurons of NCI rats. Importantly, intrathecal injection of AOAA remarkably attenuated visceral hypersensitivity of NCI rats. These results suggest that H2S modulates pain signaling likely through a presynaptic mechanism in SG of spinal dorsal horn, thus providing a potential therapeutic strategy for treatment for chronic visceral pain in patients with IBS.

This paper is concerned with the bistable wave fronts of integrodifference equations. The existence, uniqueness, and asymptotic stability of bistable wave fronts for such an equation are proved by the squeezing technique based on comparison principle.

Neutral polymer bonding agents (NPBAs) have proven highly effective in enhancing the interfacial bonding between the bonding matrix and nitramine explosives such as cyclic trimethylene trinitramine (RDX) and cyclic tetramethylene trinitramine (HMX). However, there is a lack of clear understanding of the mechanisms behind their interactions, and it has been found that NPBAs produce different interfacial bonding effects on RDX and HMX. To gain deeper insights into the molecular-scale interfacial interactions of nitramine explosives/NPBAs, this study investigated the molecular electrostatic potentials, intermolecular interactions, surface structural features, and interfacial adsorption of a NPBA onto nitramine explosives using the density functional theory and molecular dynamics (MD) technique. The results indicate that the N atom on the cyano group of the NPBA molecule can form weak hydrogen bonds C-H...N☰ C and C-H...O with the H atoms in the RDX and HMX molecules. The strength of such weak hydrogen bonding interactions is affected by the electrostatic potential range of nitramine molecules. Additionally, the surface structure of the nitramine plays a critical role in the NPBA adsorption strength. Compared to HMX, RDX exhibits a narrower surface electrostatic potential range and smoother crystal surface, resulting in weaker intermolecular interactions between the NPBA and the RDX surface. [ABSTRACT FROM AUTHOR]

P- and S-wave separation plays an important role in elastic reverse-time migration. It can reduce the artifacts caused by crosstalk between different modes and improve image quality. In addition, P- and Swave separation can also be used to better understand and distinguish wave types in complex media. At present, the methods for separating wave modes in anisotropic media mainly include spatial nonstationary filtering, low-rank approximation, and vector Poisson equation. Most of these methods require multiple Fourier transforms or the calculation of large matrices, which require high computational costs for problems with large scale. In this paper, an efficient method is proposed to separate the wave mode for anisotropic media by using a scalar anisotropic Poisson operator in the spatial domain. For 2D problems, the computational complexity required by this method is 1/2 of the methods based on solving a vector Poisson equation. Therefore, compared with existing methods based on pseudo-Helmholtz decomposition operators, this method can significantly reduce the computational cost. Numerical examples also show that the P and S waves decomposed by this method not only have the correct amplitude and phase relative to the input wavefield but also can reduce the computational complexity significantly. [ABSTRACT FROM AUTHOR]

Background: Childhood obesity tends to persist into adulthood, predisposing individuals to cardiometabolic risk (CMR). This study aims to investigate the mediating role of cardiorespiratory fitness (CRF) in the associations between multiple fatness indicators and individual CMR markers and clustered CMRscore, and explore sex differences. Methods: We recruited 1,557 children (age: 8 to 10, male/female: 52.7%/ 47.3%) in September 2022 in Ningbo, China. Physical examinations, overnight fasting blood test, and CRF was evaluated. The CMR-score was calculated by summing age- and sex-specific z scores of four CMRmarkers, including mean arterial blood pressure, triglycerides, the total cholesterol to high-density lipoprotein cholesterol ratio, and homeostatic model assessment for insulin resistance. Generalized linear mixed models were used to identify the associations, mediation analyses were performed to dissect the function of CRF. Results: Partial correlation analyses revealed positive associations between high fatness indicators (including body mass index [BMI], BMI z score, body fat mass index [BFMI] and waist-to-height ratio [WHtR]) and increased CMR markers, whereas high CRF was associated with decreased CMR markers (all P < 0.05). In the mediation analyses, CRF emerged as a partial mediator, attenuating the relationship between four fatness indicators and CMR-score. Specifically, CRF mediated 6.5%, 7.7%, 5.3%, and 12.5% of the association between BMI, BMI z score, BFMI, WHtR and CMR-score (all P < 0.001). And the mediating effects of CRF between WHtR and four individual CMR markers was particularly robust, ranging from 10.4% to 21.1% (all P < 0.05). What's more, CRF mediates the associations between WHtR and CMR-score more pronounced in girls than boys with a mediation effect size of 17.3% (P < 0.001). Conclusion: In Chinese children, CRF partially mitigates the adverse effects of fatness on CMR, underscoring the significance of enhancing CRF in children. [ABSTRACT FROM AUTHOR]