No abstract

Intelligent indoor robotics is expected to rapidly gain importance in crucial areas of our modern society such as at-home health care and factories. Yet, existing mobile robots are limited in their abilities to perceive and respond to dynamically evolving complex indoor environment because of their inherently limited sensing and computing resources that are moreover traded off against their cruise time and payload. To address these formidable challenges, here we propose intelligent indoor metasurface robotics (I2MR), where all sensing and computing are relegated to a centralized robotic brain endowed with microwave perception; and I2MR’s limbs (motorized vehicles, airborne drones, etc.) merely execute the wirelessly received instructions from the brain. The key of our concept is the centralized use of a computation-enabled programmable metasurface that can flexibly mold the microwave propagation in the indoor wireless environment, including a sensing and localization modality based on configurational diversity and a communication modality to establish a preferential high-capacity wireless link between the I2MR’s brain and limbs. The metasurface-enhanced microwave perception is capable of realizing low-latency and high-resolution three-dimensional imaging of humans, even around corners and behind thick concrete walls, which is the basis for action decisions of the I2MR’s brain. I2MR is thus endowed with real-time and full-context awareness of its operating indoor environment. We implement experimentally a proof-of-principle demonstration at around 2.4 GHz, in which I2MR provides health-care assistance to a human inhabitant. The presented strategy opens a new avenue for the conception of smart and wirelessly networked indoor robotics.

BackgroundBladder cancer is the most common malignant tumor of the urinary tract. We aimed to explore the biological role and molecular mechanism of Nodal in bladder cancer.Materials and methodsThe expression of Nodal in bladder cancer tissues and cells was determined by quantitative real-time polymerase chain reaction. The effect of silencing of Nodal on cell proliferation, clone formation, and migration and invasion was evaluated by MTT cell proliferation assay, colony formation, and transwell assays, respectively. Western blot analysis was employed to detect the expression of proliferation- and invasion-related proteins and proteins involved in ALK/Smad signaling.ResultsWe found that the expression of Nodal was significantly increased in bladder cancer tissues and cell lines. Downregulation of Nodal effectively weakened cell proliferation, clone formation, and cell migration and invasion abilities. The protein expression levels of CDC6, E-cadherin, MMP-2, and MMP-9 were also altered by downregulation of Nodal. Knockdown of Nodal also blocked the expression of ALK4, ALK7, Smad2, and Smad4, which are involved in ALK/Smad signaling. Additionally, the ALK4/7 receptor blocker SB431542 reversed the promotive effects of Nodal overexpression on bladder cancer cell proliferation, migration, and invasion.ConclusionOur study indicated that Nodal functions as an oncogene by regulating cell proliferation, migration, and invasion in bladder cancer via the ALK/Smad signaling pathway, thereby providing novel insights into its role in bladder cancer treatment.

We present an experimental prototype of a microwave speech recognizer empowered by a programmable metasurface that can recognize voice commands and speaker identities remotely even in noisy environments and if the speaker’s mouth is hidden behind a wall or face mask. Thereby, we enable voice-commanded human machine interactions in many important but to-date inaccessible application scenarios, including smart health care and factory scenarios. The programmable metasurface is the pivotal hardware ingredient of our system because its large aperture and huge number of degrees of freedom allows our system to perform a complex sequence of tasks, orchestrated by artificial-intelligence tools. First, the speaker’s mouth is localized by imaging the scene and identifying the region of interest. Second, microwaves are efficiently focused on the speaker’s mouth to encode information about the vocalized speech in reflected microwave biosignals. The efficient focusing on the speaker’s mouth is the origin of our system’s robustness to various types of parasitic motion. Third, a dedicated neural network directly retrieves the sought-after speech information from the measured microwave biosignals. Relying solely on microwave data, our system avoids visual privacy infringements. We expect that the presented strategy will unlock new possibilities for future smart homes, ambient-assisted health monitoring and care, smart factories, as well as intelligent surveillance and security.