Effect of long-term weightlessness on retina and optic nerve in tail-suspension rats

AIM： To evaluate the effect of long weightlessness on retina and optic nerve in suspension （TS） rats. -term tail METHODS： A stimulated weightlessness model was established by suspending rats tail. After 12wk, the ultrastructure and the number of optic nerve axons were observed by transmission electron microscope. The number of survival retinal ganglion cells （RGCs） was calculated by fluorescent gold retrograde labeling. Retina cells apoptosis was detected by TUNEL staining. The function of optic nerve and retina was evaluated by the visual evoked potential （VEP） and oscillatory potentials （Ops）. RESULTS： The optic nerve axons were swollen and sparsely aligned, and the lamellar separation and myelin disintegration occurred after 12wk in TS rats. The density of optic nerve axons was 32.23±3.92 （ ys 37.43±4.13, P= 0.0145）, the RGCs density was 1645 ±46 cells/mm^2 （vs 1867±54 cells/mm^2 F=0.0000）, the incidence rate of retinal cells apoptosis was 5.38%±0.53% （ vs 4.75%±0.54%, P= 0.0238）, the amplitude of VEP-P100 was 15.43±2.14 μV （vs 17.67±2.17 μV, P=0.0424）, the latency of VEP-P100 was 69.05v5.34ms （vs 62.43±4.87ms P=0.0143） and the sum amplitude of Ops was 81.05±8.34 μV （Ys 91.67± 10.21 μV, P=0.0280） in TS group and the control group, respectively. CONCLUSION： Long-term weightlessness can induce the ultrastructural changes and functional depress of the optic nerve, as well as retinal cell damages in TS rats.

Electrically conductive and highly compressible anisotropic MXene-wood sponges for multifunctional and integrated wearable devices

Although piezoresistive sensors have wide applications in human motion detection and wearable elec-tronics,it is still a challenge to produce multifunctional and integrated sensors with wide working ranges and linear sensing responses.Herein,electrically conductive,highly compressible,and structurally anisotropic MXene-wood(MW)sponges are fabricated by converting balsa wood blocks to compressible wood sponges with extremely low density and highly anisotropic porous structure,followed by deco-rating with conductive MXene sheets.The MW sponge is utilized to assemble a piezoresistive sensor with a large working range of 0-25 kPa,wide linear sensing ranges of 5%-50%and 0-180°,and excellent long-term reliability under a bending angle of 30°for 5000 cycles.Additionally,the sensor is suitable for monitoring practical human physiological signals including pulse beating,and finger and wrist bending.An all-MW sponge-based multifunctional and integrated sensing system is constructed by integrating the MW sponge piezoresistive sensor,the MW sponge-based solid-state supercapacitor,and the MW sponge electrophysiological electrodes.The sensing system can concurrently detect surface electromyogram and tactile pressures,and hence realize real-time closed-loop controls.The multifunctional and integrated MW sponge sensing system would have great potentials in real-time pressure recognition and human-machine interfaces.