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Quantum metrology [1-4] enables a measurement sensitivity below the standard quantum limit (SQL), as demonstrated in the Laser Interferometer Gravitational-wave Observatory (LIGO) [5,6]. As a unique quantum resource, entanglement has been utilized to enhance the performance of, e.g., microscopy [7], target detection [8], and phase estimation [9]. To date, almost all existing entanglementenhanced sensing demonstrations are restricted to improving the performance of probing optical parameters at a single sensor, but a multitude of applications rely on an array of sensors that work collectively to undertake sensing tasks in the radiofrequency (RF) and microwave spectral ranges. Here, we propose and experimentally demonstrate a reconfigurable RF-photonic sensor network comprised of three entangled sensor nodes. We show that the entanglement shared by the sensors can be tailored to substantially increase the precision of parameter estimation in networked sensing tasks, such as estimating the angle of arrival (AoA) of an RF field. Our work would open a new avenue toward utilizing quantum metrology for ultrasensitive positioning, navigation, and timing.A variety of sensing scenarios commonly operate in the RF and microwave spectral ranges, rather than at the optical wavelengths like LIGO, thus requiring a different mechanism to achieve a quantum enhancement. In this regard, quantum illumination enables a signal-to-noise ratio (SNR) advantage over classical schemes in the RF and microwave where ambient noise is abundant [8,[10][11][12][13][14], but quantum illumination's operational range and quantum enhancement are limited by large diffraction in the microwave and a lack of efficient quantum memories.Recent advances in RF and microwave photonics [15] offer new insights for sensing. In RF-photonic sensing, RF signals are carried over to the optical domain by * zsz@email.arizona.edu † Equal contributions

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Parkinson's disease (PD) is characterized by a progressive degeneration of dopaminergic neurons in the substantia nigra. Oxidative stress and neural degeneration are suggested to be involved in the pathogenesis of PD. Previous studies have revealed that Astragaloside IV (AS-IV) can reduce inflammation and oxidation, making it a potential therapeutic agent for neurodegenerative disease. In this study, we investigated whether AS-IV protect against 1-methyl-4-phenylpyridnium ion (MPP(+))-induced dopaminergic neurotoxicity in SH-SY5Y cells and determined the mechanism of AS-IV neuroprotection. We found that pretreatment with AS-IV significantly reversed the loss of cell viability, nuclear condensation, the generation of intracellular reactive oxygen species (ROS), and the increase in Bax/Bcl-2 ratio and the activity of caspase-3 induced by MPP(+). Our study suggests that the neuroprotective effect of AS-IV is related to mechanisms including ROS production and the inhibition of Bax-mediated pathway. The present study supports the notion that AS-IV may be a promising neuroprotective agent for the treatment of neurodegenerative disorders such as PD.