The propagation of laser-generated Lamb waves in a two-dimensional acoustic black-hole structure was studied numerically and experimentally. The geometrical acoustic theory has been applied to calculate the beam trajectories in the region of the acoustic black hole. The finite element method was also used to study the time evolution of propagating waves. An optical system based on the laser-Doppler vibration method was assembled. The effect of the focusing wave and the reduction in wave speed of the acoustic black hole has been validated.
Recently, the concept of valley pseudospin, labeling quantum states of energy extrema in momentum space, has attracted enormous attention because of its potential as a new type of information carrier. Here, we present surface acoustic wave (SAW) waveguides, which utilize and transport valley pseudospins in two-dimensional SAW phononic crystals (PnCs). In addition to a direct visualization of the valley-dependent states excited from the corresponding chiral sources, the backscattering suppression of SAW valley-dependent edge states transport is observed in sharply curved interfaces. By means of band structure engineering, elastic wave energy in the SAW waveguides can be transported with remarkable robustness, which is very promising for new generations of integrated solid-state phononic circuits with great versatility.Valley, an intriguing and significant concept in condensed matter physics, stems from the extensive research of two dimensional (2D) hexagonal crystals, such as graphene, bilayer graphene, and transition-metal dichalcogenides, in recent years. [1][2][3][4][5][6][7][8][9][10][11][12][13] When the inversion symmetry is broken in two-dimensional (2D) hexagonal lattices, the berry curvatures will acquire opposite signs at K and K' points due to time-reversal symmetry. Subsequently, the electrons in different valleys own opposite anomalous velocities and move towards the opposite directions. Additionally, slow valley relaxation and dephasing processes, compared to electron spin, can be accessed due to the reason that intervalley scattering is suppressed by large momentum separation between different valleys. 2,3,12,14
Recently, circular RNAs have been shown to function as critical regulators of many human cancers. However, the circRNA mechanism in laryngeal squamous cell carcinoma (LSCC) remains elusive. Recent investigations using bioinformatics analysis revealed high expression of hsa_circ_0023305 in LSCC tissues compared to normal tissues. Furthermore, we discovered that hsa_circ_0023305 expression level was positively correlated to tumor/node/metastasis (TNM) stage as well as lymph node metastasis in LSCC. Moreover, higher hsa_circ_0023305 levels were correlated to poorer LSCC patient outcomes. Knockdown of hsa_circ_0023305 significantly inhibited LSCC cell proliferation, invasion, and migration abilities. Our team validated that hsa_circ_0023305 functioned as a miR-218-5p sponge from a mechanistic perspective, targeting the melastatin-related transient receptor potential 7 (TRPM7) in LSCC cells. TRPM7 regulates a nonselective cation channel and promotes cancer proliferation and metastasis. Our data demonstrated that miR-218-5p was downregulated in LSCC and that miR-218-5p upregulation repressed LSCC proliferation and invasion both in vivo and in vitro. Additionally, we found that hsa_circ_0023305-mediated upregulation of TRPM7 inhibited miR-218-5p and contributed to LSCC migration, proliferation, and invasion. In summary, these data propose a new mechanism by which the hsa_circ_0023305/miR-218-5p/TRPM7 network enhances LSCC progression.
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