Using brefeldin A to disrupt cell wall polysaccharide components in rice and nitric oxide to modify cell wall structure to change aluminum tolerance.

The components and structure of cell wall are closely correlated with aluminum (Al) toxicity and tolerance for plants. However, the cell wall assembly and function construction in response to Al is not known. Brefeldin A (BFA), a macrolide, is used to disrupt cell wall polysaccharide components, and nitric oxide (NO), a signal molecule, is used to modify the cell wall structure. Pretreatment with BFA accelerated Al accumulation in root tips and Al-induced inhibition of root growth of two rice genotypes of Nipponbare and Zhefu 802, and significantly decreased the cell wall polysaccharide content including pectin, hemicellulose 1, and hemicellulose 2, indicating that BFA inhibits the biosynthesis of components in the cell wall and makes the root cell wall lose the ability to resist Al. The addition of NO donor (SNP) significantly alleviated the toxic effects of Al on root growth, Al accumulation, and oxidative damage, and decreased the content of pectin polysaccharide and functional groups of hydroxyl, carboxyl, and amino in the cell wall via FTIR analysis, while had no significant effect on hemicellulose 1 and hemicellulose 2 content compared with Al treatment. Furthermore, NO didn't change the inhibition effect of BFA-induced cell wall polysaccharide biosynthesis and root growth. Taken together, BFA disrupts the integrity of cell wall and NO modifies partial cell wall composition and their functional groups, which change the Al tolerance in rice.

Noninvasive Estimation of Joint Moments with Inertial Sensor System for Analysis of STS Rehabilitation Training.

An original approach for noninvasive estimation of lower limb joint moments for analysis of STS rehabilitation training with only inertial measurement units was presented based on a piecewise three-segment STS biomechanical model and a double-sensor difference based algorithm. Joint kinematic and kinetic analysis using a customized wearable sensor system composed of accelerometers and gyroscopes were presented and evaluated compared with a referenced camera system by five healthy subjects and five patients in rehabilitation. Since there is no integration of angular acceleration or angular velocity, the result is not distorted without offset and drift. Besides, since there are no physical sensors implanted in the lower limb joints based on the algorithm, it is feasible to noninvasively analyze STS kinematics and kinetics with less numbers and types of inertial sensors than those mentioned in other methods. Compared with the results from the reference system, the developed wearable sensor system is available to do spatiotemporal analysis of STS task with fewer sensors and high degree of accuracy, to apply guidance and reference for rehabilitation training or desired feedback for the control of powered exoskeleton system.

Nondestructive Estimation of Muscle Contributions to STS Training with Different Loadings Based on Wearable Sensor System.

Partial body weight support or loading sit-to-stand (STS) rehabilitation can be useful for persons with lower limb dysfunction to achieve movement again based on the internal residual muscle force and external assistance. To explicate how the muscles contribute to the kinetics and kinematics of STS performance by non-invasive in vitro detection and to nondestructively estimate the muscle contributions to STS training with different loadings, a wearable sensor system was developed with ground reaction force (GRF) platforms, motion capture inertial sensors and electromyography (EMG) sensors. To estimate the internal moments of hip, knee and ankle joints and quantify the contributions of individual muscle and gravity to STS movement, the inverse dynamics analysis on a simplified STS biomechanical model with external loading is proposed. The functional roles of the lower limb individual muscles (rectus femoris (RF), gluteus maximus (GM), vastus lateralis (VL), tibialis anterior (TA) and gastrocnemius (GAST)) during STS motion and the mechanism of the muscles' synergies to perform STS-specific subtasks were analyzed. The muscle contributions to the biomechanical STS subtasks of vertical propulsion, anteroposterior (AP) braking and propulsion for body balance in the sagittal plane were quantified by experimental studies with EMG, kinematic and kinetic data.