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The activation of cochlear progenitor cells is a promising approach for hair cell (HC) regeneration and hearing recovery. The mechanisms underlying the initiation of proliferation of postnatal cochlear progenitor cells and their transdifferentiation to HCs remain to be determined. We show that Notch inhibition initiates proliferation of supporting cells (SCs) and mitotic regeneration of HCs in neonatal mouse cochlea in vivo and in vitro. Through lineage tracing, we identify that a majority of the proliferating SCs and mitotic-generated HCs induced by Notch inhibition are derived from the Wnt-responsive leucine-rich repeat-containing G proteincoupled receptor 5 (Lgr5+) progenitor cells. We demonstrate that Notch inhibition removes the brakes on the canonical Wnt signaling and promotes Lgr5+ progenitor cells to mitotically generate new HCs. Our study reveals a new function of Notch signaling in limiting proliferation and regeneration potential of postnatal cochlear progenitor cells, and provides a new route to regenerate HCs from progenitor cells by interrupting the interaction between the Notch and Wnt pathways. [ABSTRACT FROM AUTHOR]

Ultrasound-assisted emulsification-microextraction coupled to HPLC was applied to the determination of propoxur in environmental and beverage samples. Carbon tetrachloride (the extraction solvent) is added to the aqueous sample, and the liquids are sonificated at 60 °C, upon which an emulsion is formed. This is followed by centrifugation the lower phase being analyzed by HPLC. The extraction solvent, its volume, extraction time, temperature and salt concentration were optimized. Linear range (0.01–10 µg mL-1), correlation coefficient (0.9965), detection limit (1 ng mL-1 at a SNR of 3), and precision (4.5% RSD, n = 5) were determined. The technique was applied to the determination of propoxur in environmental and beverage samples and no target analyte was found in these samples. Therefore, samples were spiked and recoveries of 93–106% and RSDs of 1.5–6.2% were obtained. [ABSTRACT FROM AUTHOR]

The generation of hair cells (HCs) from the differentiation of proliferating supporting cells (SCs) appears to be an ideal approach for replacing lost HCs in the cochlea and is promising for restoring hearing after damage to the organ of Corti. We show here that extensive proliferation of SCs followed by mitotic HC generation is achieved through a genetic reprogramming process involving the activation of β-catenin to upregulateWntsignaling, the deletion of Notch1 to downregulate Notch signaling, and the overexpression of Atoh1 in Sox2+ SCs in neonatal mouse cochleae. We used RNA sequencing to compare the transcripts of the cochleae from control mice and from mice with β-catenin activation, Notch1 deletion, and β-catenin activation combined with Notch1 deletion in Sox2+ SCs. We identified the genes involved in the proliferation and transdifferentiation process that are either controlled by individual signaling pathways or by the combination of Wnt and Notch signaling. Moreover, the proliferation of SCs induced by Notch1 deletion disappears after deleting β-catenin in Notch1 knock-out Sox2+ cells, which further demonstrates that Notch signaling is an upstream and negative regulator of Wnt signaling. [ABSTRACT FROM AUTHOR]

Traditional bistable stochastic resonance has been demonstrated as an effective tool to detect the weak signal in a strong noise background. To achieve a better signal-to-noise ratio for the output signal, a coupled stochastic resonance was developed by nonlinearly coupling two double-well potential systems. The response characteristics of coupled stochastic resonance subjected to analytical signals have been investigated and compared with those of bistable stochastic resonance. The improvement of chromatographic determination with the proposed coupled stochastic resonance was validated by both simulated signals and chromatographic signals. The weak signals from both simulated data and plasma samples with different concentrations were all amplified significantly and the quantitative relationship between different concentrations and responses was kept well. It is reasonable to believe that coupled stochastic resonance could play an important role in applications where quantitative determination of low-concentration samples is crucial. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]