Bamboo delignification is a common method for studying its functional value-added applications. In this study, bamboo samples were delignified by treatment with sodium chlorite. The effects of this treatment on the bamboo’s microstructure, surface chemical composition, and pyrolysis behaviour were evaluated. Field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were conducted to evaluate these parameters. The FTIR results demonstrated that the lignin peak decreased or disappeared, and some hemicellulose peaks decreased, indicating that sodium chlorite treatment effectively removed lignin and partly decomposed hemicellulose, although cellulose was less affected. The XPS results showed that, after treatment, the oxygen-to-carbon atomic ratio of delignified bamboo increased from 0.34 to 0.45, indicating a lack of lignin. XRD revealed increased crystallinity in delignified bamboo. Further pyrolysis analysis of treated and untreated bamboo showed that, although the pyrolysis stage of the delignified bamboo did not change, the maximum thermal degradation rate (R_max) and its corresponding temperature (from 353.78 to 315.62 °C) decreased significantly, indicating that the pyrolysis intensity of the bamboo was weakened after delignification. Overall, this study showed that delignified bamboo develops loose surfaces, increased pores, and noticeable fibres, indicating that alkali-treated bamboo has promising application potential due to its novel and specific functionalities.

Waterborne polyurethane coatings (WPU) are widely used in various types of coatings due to their environmental friendliness, rich gloss, and strong adhesion. However, their inferior mechanical properties and solvent resistance limit their application on the surface of wood products. In this study, graphene oxide (GO) with nanoscale size, large surface area, and abundant functional groups was incorporated into WPU by chemical grafting to improve the dispersion of GO in WPU, resulting in excellent mechanical properties and solvent resistance of WPU coatings. GO with abundant oxygen-containing functional groups and nanoscale size was prepared, and maintained good compatibility with WPU. When the GO concentration was 0.7 wt%, the tensile strength of GO-modified WPU coating film increased by 64.89%, and the abrasion resistance and pendulum hardness increased by 28.19% and 15.87%, respectively. In addition, GO also improved the solvent resistance of WPU coatings. The chemical grafting strategy employed in this study provides a feasible way to improve the dispersion of GO in WPU and provides a useful reference for the modification of waterborne wood coatings.

Background: Sleep fragmentation is a persistent problem throughout the course of Parkinson’s disease (PD). However, the related neurophysiological patterns and the underlying mechanisms remained unclear.Method: We recorded subthalamic nucleus (STN) local field potentials (LFPs) using deep brain stimulation (DBS) with real-time wireless recording capacity from 13 patients with PD undergoing a one-night polysomnography recording, 1 month after DBS surgery before initial programming and when the patients were off-medication. The STN LFP features that characterised different sleep stages, correlated with arousal and sleep fragmentation index, and preceded stage transitions during N2 and REM sleep were analysed.Results: Both beta and low gamma oscillations in non-rapid eye movement (NREM) sleep increased with the severity of sleep disturbance (arousal index (ArI)-beta_NREM: r=0.9, p=0.0001, sleep fragmentation index (SFI)-beta_NREM: r=0.6, p=0.0301; SFI-gamma_NREM: r=0.6, p=0.0324). We next examined the low-to-high power ratio (LHPR), which was the power ratio of theta oscillations to beta and low gamma oscillations, and found it to be an indicator of sleep fragmentation (ArI-LHPR_NREM: r=−0.8, p=0.0053; ArI-LHPR_REM: r=−0.6, p=0.0373; SFI-LHPR_NREM: r=−0.7, p=0.0204; SFI-LHPR_REM: r=−0.6, p=0.0428). In addition, long beta bursts (>0.25 s) during NREM stage 2 were found preceding the completion of transition to stages with more cortical activities (towards Wake/N1/REM compared with towards N3 (p<0.01)) and negatively correlated with STN spindles, which were detected in STN LFPs with peak frequency distinguishable from long beta bursts (STN spindle: 11.5 Hz, STN long beta bursts: 23.8 Hz), in occupation during NREM sleep (β=−0.24, p<0.001).Conclusion: Features of STN LFPs help explain neurophysiological mechanisms underlying sleep fragmentations in PD, which can inform new intervention for sleep dysfunction.Trial registration number: NCT02937727.

The Deep Brain Stimulation (DBS) has become a well-accepted treatment for Parkinson's disease patients around the world. However, postoperative care of the stimulators usually puts a heavy burden on the patients' families, especially in China. To solve the problem, this study developed a real-time remote monitoring system for deep brain stimulators. Based on Internet technologies, the system offers remote adjustment service so that in vivo stimulators could be programmed at patients' home by clinic caregivers. We tested the system on an experimental condition and the results have proved that this early exploration of remote monitoring deep brain stimulators was successful.