RESUMO
Mammalian target of rapamycin (mTOR) is an intracellular signaling pathway molecule which regulates various fundamental physiological processes. The mTOR signaling pathway plays an important role in synaptic plasticity, information transmission and processing, and neuroregulation. Dysregulation of the mTOR signaling pathway is generally considered to be related to the pathogenesis of autism spectrum disorder (ASD); meanwhile, the mTOR inhibitor can ameliorate the symptoms of ASD. The role of mTOR in the pathogenesis of ASD is summarized in this article to provide a theoretical basis for targeted therapy of ASD.
Assuntos
Animais , Humanos , Transtorno do Espectro Autista , Transdução de Sinais , Sirolimo , Serina-Treonina Quinases TORRESUMO
High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range. We fabricated the matching layer by etching the peeled silica optical fibre bundles with hydrofluoric acid solution. The experimental measurement of an ultrasound transducer equipped with this acoustic metamaterial matching layer shows that the corresponding -6 dB bandwidth is able to reach over 100%. This new material fully enables new high-end piezoelectric materials in the construction of high-performance ultrasound transducers and probes, leading to considerably improved resolutions in biomedical ultrasonography and compact harmonic imaging systems.
