Content analysis of vitamins, dietary fibers and amino acids in a wide collection of barley (Hordeum vulgare L.) from Tibet, China.

Barley (Hordeum vulgare L.) is an important agricultural crop. Various studies on the genetic diversity, biochemical and molecular attributes on this species are known. However, information on nutritional variability in a large panel of barley cultivars is limited. Therefore, it is of interest for a quantitative analysis of vitamins, amino acids and dietary fibers in 245 barley of Tibet region in China. The coefficient of variation analysis revealed strong variation of vitamins (VB1>VB2>VE), essential amino acids (valine, histidine, methionine, lysine), non-essential amino acids (proline, tyrosine, cysteine), dietary fibers, (cellulose > lignin). Principal component analysis detected three clusters of cultivars, each with specific characteristics. However, the most nutritional cultivars were found in Cluster 3, which encompassed 52 cultivars. Distinctly, six cultivars (ZQ2000, BJX230, BJX229, BJX249, BJX191 and BJX265) were identified with highest nutritional values. This study reveals a large nutritional diversity in barley cultivars from Tibet and represents an important reference for the exploitation of these germplasm in crop improvement and breeding programmes.

Spinal biomechanics modeling and finite element analysis of surgical instrument interaction.

When the spinal surgery robot assists the surgeon perform the surgery, the patient is prone on the operating table. However, due to the force of the surgical instruments on the spine, there is a corresponding deformation in the surgical field, which affects the accuracy of the operation. In order to improve the accuracy and safety of the operation, this paper reconstructs the three-dimensional model of the lumbar spine which includes the vertebral body and the intervertebral disc based on the CT scan data, and then the lumbar spine is analyzed by the finite element method. The mathematical model of the relationship between force and displacement is established by using response surface methodology based on the simulation results. After that, the position control system is constructed based on the mathematical model. Through the simulation of the control system, the trajectory curve of the end of the manipulator is compared and the validity of the mathematical model is verified.