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The method for online testing of the vibration isolation track in tunnels does not differentiate among various tunnel structural forms and overlooks the influence of longitudinal joints in shield tunnels during vibration propagation. To address this issue, this study combines field testing and numerical simulation to analyze the impact of longitudinal joints in shield tunnels during vibration propagation. The research results show that the vibration wave of a single segment has a certain degree of attenuation with the increase of the distance from the vibration source, but the attenuation is not obvious; the longitudinal joints of the shield tunnel have a significant weakening effect on the vibration wave, and the maximum amplitude of the vibration acceleration can be reduced by more than 50% after passing through the longitudinal joints; no matter what the assembly angle is, there are significant differences in the amplitude and frequency distributions of vibration acceleration on the side affected by the longitudinal joints and the side unaffected by the longitudinal joints, even if they are located on the side unaffected by longitudinal joints. Regardless of the assembly angle, there are significant differences in the amplitude and frequency distribution of vibration acceleration between the side of the shield tunnel affected by the longitudinal joint and the side not affected by the longitudinal joint. Therefore, when conducting vibration testing in shield tunnels, the influence of longitudinal joint positions and segment assembly angles should be considered. [ABSTRACT FROM AUTHOR]

This research aimed to investigate the feasibility of utilizing dual-energy CT virtual monoenergetic images (VMI 1 1 VMI:virtual monoenergetic images.) with prospective electrocardiogram (ECG 2 2 ECG:electrocardiogram.) gating for reducing radiation and contrast agent doses in pediatric patients with congenital heart disease (CHD 3 3 CHD:congenital heart disease.). There were 100 pediatric patients with CHD included in this study. Group A (n = 50) underwent dual-energy scanning with prospective ECG-gating, and group B (n = 50) underwent conventional scanning with retrospective ECG-gating. Comparative analysis of CT values of lumen, objective image quality assessment, subjective image quality evaluations, and diagnostic efficacy were performed. CT values, image noise, signal-to-noise ratio (SNR 4 4 SNR:signal-to-noise ratio.), and contrast-to-noise ratio (CNR 5 5 CNR:contrast-to-noise ratio.) were significantly affected by the VMI energy level, and they all increased with decreasing energy levels (P > 0.05). Combining subjective evaluation, the 45 keV VMI was considered the optimum image in group A. The 45 keV VMI exhibited higher CT values of lumen compared to conventional scanning images (P < 0.003 ∼ 0.836), but meanwhile, the image noise was also higher in the 45 keV VMI (P = 0.004). Differences between the two groups in SNR, CNR, and diagnostic accuracy were not statistically significant. Compared to group B, the 45 keV VMI showed fewer contrast-induced artifacts (P < 0.001) and higher image quality score (P = 0.037). Group A had a 64 % reduction in radiation dose and a 40 % decrease in iodine dose compared to group B. The combination of dual-energy CT with prospective ECG-gating reduces radiation and iodine doses in pediatric patients with CHD. The 45 keV VMI can provide clinically acceptable image quality while declining contrast agent artifacts. [ABSTRACT FROM AUTHOR]

Hepatitis B virus (HBV) core protein (HBc) plays a crucial role in the virus life cycle, making it an important detection marker for HBV infection and a potential target for treatment. However, several commercially available monoclonal antibodies (mAbs) or polyclonal antibodies (pAbs) targeting HBc have certain limitations in detecting HBV across different genotypes in various biochemical assays, such as enzyme-linked immunosorbent assay, western blot, immunofluorescence assay, flow cytometry, and immune spot assay. In this study, we identified 12 human anti-HBc mAbs and evaluated their potential application in multiple biochemical assays. These mAbs mainly recognized the epitopes near residues 20-22 amino acids (a.a.) and 77-78 a.a. of HBc, demonstrating a broadly cross-genotypic activity. Notably, three Group II mAbs, named cAbA1, cAbD4, and cAbF9, displayed excellent capacities for the detection of HBV infection in all tested biochemical assays. Furthermore, we determined a 3.22 Å of cryo-electron microscopy (cryo-EM) structure of the fragment of antigen binding (Fab) of cAbD4 complexed with HBc dimer, which was the highest resolution of the structural model for Fab-HBc to date. Collectively, our findings provided excellent and reliable antibody candidates for live HBV detection and revealed the recognition mechanism and the detailed interaction information of a potent human anti-HBc mAb binding to the spike tips of HBc dimer.IMPORTANCEThe lack of excellent detection Abs for live hepatitis B virus (HBV) infection and high-resolution structures of the Ab-HBV core protein (HBc) complex largely limited the development of HBV-related research. This study reports a panel of anti-HBc monoclonal antibodies (mAbs) with excellent capacities for detecting HBV infection in multiple biochemical assays and determines a 3.22 Å of cryo-EM structure of HBc with a potent binding mAb. These findings provide excellent and reliable detecting tools for HBV-related research and promote the understanding of the recognition mechanism of anti-HBc mAbs to HBc particles.

Purpose: We evaluated brain iron content in a healthy pediatric population using quantitative susceptibility mapping (QSM)., Methods: From June 2018 to December 2019, healthy subjects aged 2-18 years old (200 males, 200 females) with no anatomical abnormalities were assessed. All of the children underwent 3D T1 anatomical MRIs in addition to the sequence scans of enhanced T2 star-weighted angiography (ESWAN). The ESWAN sequence images were obtained with software to attain quantitative susceptibility mapping of the entire brain. The magnetic susceptibility values in the same brain region were compared across different age groups. The magnetic susceptibility values expressed in the same age group were compared across sexes, brain sides, and brain regions., Results: The magnetic susceptibility value of each brain region increased with age, and the magnetic susceptibility value expressed by each brain region demonstrated a positive correlation with the children's age (r=0.63, P<0.05). No dramatic difference in magnetic susceptibility was observed between the brain's left side and right side in the children within the age range ≥2-<6; however, among the children within the age range ≥6-<18, the magnetic susceptibility values expressed by the left putamen nucleus, globus pallidus, and substantia nigra were higher than those expressed by the same regions on the right side (P<0.05)., Conclusion: Quantitative susceptibility mapping can be used to evaluate the content of iron in each brain region of normal children., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)