Viscoelastic modulus reconstruction using time harmonic vibrations

This paper presents a new iterative reconstruction method to provide high-resolution images of shear modulus and viscosity via the internal measurement of displacement fields in tissues. To solve the inverse problem, we compute the Fr\'echet derivatives of the least-squares discrepancy functional with respect to the shear modulus and shear viscosity. The proposed iterative reconstruction method using this Fr\'echet derivative does not require any differentiation of the displacement data for the full isotropic linearly viscoelastic model, whereas the standard reconstruction methods require at least double differentiation. Because the minimization problem is ill-posed and highly nonlinear, this adjoint-based optimization method needs a very well-matched initial guess. We find a good initial guess. For a well-matched initial guess, numerical experiments show that the proposed method considerably improves the quality of the reconstructed viscoelastic images.Comment: 15 page

Electrical impedance spectroscopy-based nondestructive testing for imaging defects in concrete structures

An electrical impedance spectroscopy-based nondestructive testing (NDT) method is proposed to image both cracks and reinforcing bars in concrete structures. The method utilizes the frequency-dependent behavior of thin insulating cracks: low-frequency electrical currents are blocked by insulating cracks, whereas high-frequency currents can pass through the conducting bars without being blocked by thin cracks. Rigorous mathematical analysis relates the geometric structures of the cracks and bars to the frequency-dependent Neumann-to-Dirichlet data. Various numerical simulations support the feasibility of the proposed method

The SO(5)\mathrm{SO}(5) Deconfined Phase Transition under the Fuzzy Sphere Microscope: Approximate Conformal Symmetry, Pseudo-Criticality, and Operator Spectrum

The deconfined quantum critical point (DQCP) is an example of phase transitions beyond the Landau symmetry breaking paradigm that attracts wide interest. However, its nature has not been settled after decades of study. In this paper, we apply the recently proposed fuzzy sphere regularization to study the $\mathrm{SO}(5)$ non-linear sigma model (NL$\sigma$M) with a topological Wess-Zumino-Witten term, which serves as a dual description of the DQCP with an exact $\mathrm{SO}(5)$ symmetry. We demonstrate that the fuzzy sphere functions as a powerful microscope, magnifying and revealing a wealth of crucial information about the DQCP, ultimately paving the way towards its final answer. In particular, through exact diagonalization, we provide clear evidence that the DQCP exhibits approximate conformal symmetry. The evidence includes the existence of a conserved $\mathrm{SO}(5)$ symmetry current, a stress tensor, and integer-spaced levels between conformal primaries and their descendants. Most remarkably, we have identified 19 conformal primaries and their 82 descendants. Furthermore, by examining the renormalization group flow of the lowest symmetry singlet, we demonstrate that the DQCP is more likely pseudo-critical, with the approximate conformal symmetry plausibly emerging from nearby complex fixed points. Our computed primary spectrum also has important implications, including the conclusion that the $\mathrm{SO}(5)$ DQCP cannot describe a direct transition from the N\'eel to valence bond solid phase on the honeycomb lattice.Comment: 17 pages, 6 figures and 6 table

Glymphatic clearance estimated using diffusion tensor imaging along perivascular spaces is reduced after traumatic brain injury and correlates with plasma neurofilament light, a biomarker of injury severity

The glymphatic system is a perivascular fluid clearance system, most active during sleep, considered important for clearing the brain of waste products and toxins. Glymphatic failure is hypothesized to underlie brain protein deposition in neurodegenerative disorders like Alzheimer's disease. Preclinical evidence suggests that a functioning glymphatic system is also essential for recovery from traumatic brain injury, which involves release of debris and toxic proteins that need to be cleared from the brain. In a cross-sectional observational study, we estimated glymphatic clearance using diffusion tensor imaging along perivascular spaces, an MRI-derived measure of water diffusivity surrounding veins in the periventricular region, in 13 non-injured controls and 37 subjects who had experienced traumatic brain injury ∼5 months previously. We additionally measured the volume of the perivascular space using T2-weighted MRI. We measured plasma concentrations of neurofilament light chain, a biomarker of injury severity, in a subset of subjects. Diffusion tensor imaging along perivascular spaces index was modestly though significantly lower in subjects with traumatic brain injury compared with controls when covarying for age. Diffusion tensor imaging along perivascular spaces index was significantly, negatively correlated with blood levels of neurofilament light chain. Perivascular space volume did not differ in subjects with traumatic brain injury as compared with controls and did not correlate with blood levels of neurofilament light chain, suggesting it may be a less sensitive measure for injury-related perivascular clearance changes. Glymphatic impairment after traumatic brain injury could be due to mechanisms such as mislocalization of glymphatic water channels, inflammation, proteinopathy and/or sleep disruption. Diffusion tensor imaging along perivascular spaces is a promising method for estimating glymphatic clearance, though additional work is needed to confirm results and assess associations with outcome. Understanding changes in glymphatic functioning following traumatic brain injury could inform novel therapies to improve short-term recovery and reduce later risk of neurodegeneration

Yttrium triflate-catalyzed reactions of indoles with electron-deficient olefins

481-484The reaction condition for Michael addition of indoles to a series of electron-deficient olefins catalyzed by Y(OTf)₃ has been carefully optimized at ambient temperature and the reaction affords the corresponding Michael adducts in good to excellent yields with high selectivity. Y(OTf)₃ is also found to be able to catalyze the Michael addition of furan

ZnO Nanorods Grown on Rhombic ZnO Microrods for Enhanced Photocatalytic Activity

In this paper, the formation of rhombic ZnO microrods surrounded by ZnO nanorods was realized on the surfaces of zinc foils using a hydrothermal method. The photocatalytic degradation of Rhodamine B solution was used to test the photocatalytic performance of the prepared samples. Compared with the rhombic Zn(OH)F and ZnO microrods grown on zinc foils, the hierarchical micro/nanostructures formed by ZnO nanorods surrounding the surfaces of rhombic ZnO microrods have better photocatalytic performance. The experimental results are mainly due to the fact that the hierarchical ZnO micro/nanostructures formed by ZnO nanorods surrounding the surface of the rhombic ZnO microrods have a larger surface area compared with the rhombic Zn(OH)F and ZnO microrods. More importantly, the photocatalytic circulation experiments indicate that ZnO nanorods grown on rhombic ZnO microrods can be recycled and have a relatively stable photocatalytic performance

Analysis of the Partial Nitrification/Anammox Performance and Microbial Structure of Low C/N Wastewater by A²/O Process

Given the carbon limitation of low C/N wastewater, the improvement of nitrogen-removal efficiency remains a challenging task of municipal wastewater treatment plants (WWTPs) in China. In this study, a partial nitrification/anammox (PN/A) system was established to facilitate the anaerobic-anoxic-aerobic (A2/O) treatment of low C/N (C/N = 3) wastewater with insufficient carbon sources. Effects of dissolved oxygen (DO) concentration and internal reflux ratio on nitrogen-removal efficiency and pathway were investigated. Under the optimal DO (0.5–0.8 mg·L−1) and internal reflux ratio (250%), the highly efficient NH4+-N removal (97.21%) and TN removal (80.92%) were achieved based on PN/A. Moreover, the relative abundance of ammonia-oxidizing bacteria (Nitrosomonas) was 3 times higher than the abundance of nitrite-oxidizing bacteria (Nitrospira) in phase V, which was the main cause of PN in the reactor. Anaerobic ammonia-oxidizing bacteria (Candidatus Brocadia, Pirellula, and Gemmata) were also found and considered as the key microbes involved in anammox. This study reports that the A2/O process can achieve advanced nitrogen removal of low C/N wastewater based on PN/A by optimizing conventional process parameters. The outcomes of this study may provide practical engineering applications as a reference for nitrogen removal based on the A2/O process

KIF3C Promotes Proliferation, Migration, and Invasion of Glioma Cells by Activating the PI3K/AKT Pathway and Inducing EMT

Kinesin superfamily protein 3C (KIF3C), a motor protein of the kinesin superfamily, is expressed in the central nervous system (CNS). Recently, several studies have suggested that KIF3C may act as a potential therapeutic target in solid tumors. However, the exact function and possible mechanism of the motor protein KIF3C in glioma remain unclear. In this study, a variety of tests including CCK-8, migration, invasion, and flow cytometry assays, and western blot were conducted to explore the role of KIF3C in glioma cell lines (U87 and U251). We found that overexpression of KIF3C in glioma cell lines promoted cell proliferation, migration, and invasion and suppressed apoptosis, while silencing of KIF3C reversed these effects. Ectopic KIF3C also increased the expression of N-cadherin, vimentin, snail, and slug to promote the epithelial-mesenchymal transition (EMT). Mechanistically, overexpression of KIF3C increased the levels of phosphatidylinositol 3-kinase (PI3K) and phosphorylated protein kinase B (p-AKT). These responses were reversed by KIF3C downregulation or AKT inhibition. Our results indicate that KIF3C promotes proliferation, migration, and invasion and inhibits apoptosis in glioma cells, possibly by activating the PI3K/AKT pathway in vitro. KIF3C might act as a potential biomarker or therapeutic target for further basic research or clinical management of glioma