Multi-Layer Polyurethane-Fiber-Prepared Entangled Strain Sensor with Tunable Sensitivity and Working Range for Human Motion Detection.

The entanglement of fibers can form physical and topological structures, with the resulting bending and stretching strains causing localized changes in pressure. In this study, a multi-layer polyurethane-fiber-prepared (MPF) sensor was developed by coating the CNT/PU sensing layer on the outside of an elastic electrode through a wet-film method. The entangled topology of two MPFs was utilized to convert the stretching strain into localized pressure at the contact area, enabling the perception of stretching strain. The influence of coating mechanical properties and surface structure on strain sensing performance was investigated. A force regulator was introduced to regulate the mechanical properties of the entangled topology of MPF. By modifying the thickness and length proportion of the force regulator, the sensitivity factor and sensitivity range of the sensor could be controlled, achieving a high sensitivity factor of up to 127.74 and a sensitivity range of up to 58%. Eight sensors were integrated into a sensor array and integrated into a dance costume, successfully monitoring the multi-axis motion of the dancer's lumbar spine. This provides a new approach for wearable biomechanical sensors.

Identification and characterization of serine acetyltransferase encoded by the Mycobacterium tuberculosis Rv2335 gene.

Serine acetyltransferase (CysE) is the first enzyme involved in the two-step enzymatic pathway of L-cysteine biosynthesis in bacteria and plants, but not in humans. CysE catalyzes the biosynthesis of O-acetyl-L-serine and CoA from L-serine (L-Ser) and acetyl-CoA (AcCoA). Mycobacterium tuberculosis (M. tuberculosis) Rv2335 was predicted as the cysE gene encoding serine acetyltransferase. In this study, the M. tuberculosis Rv2335 gene was cloned and the CysE protein was expressed in E. coli BL21 (DE3). The M. tuberculosis CysE protein was purified by Ni(2+) affinity chromatography and confirmed by SDS-PAGE, western blotting and mass spectrometry. The serine acetyltransferase activity of the M. tuberculosis CysE protein was detected using Ellman's reagent. M. tuberculosis CysE displayed optimal activity at pH 7.5 and 37˚C. The Michaelis constant for AcCoA and L-Ser was 0.0513±0.0050 and 0.0264±0.0006 mM, respectively. The maximum velocity (V(max)) for CysE was 0.0073±0.0005 mM/min. The CysE assay and the determination of the kinetic parameters of M. tuberculosis CysE may be helpful for screening its inhibitors in anti-tuberculosis drug discovery.