Automatic measurement of axial vertebral rotation in 3D vertebral models.

Axial Vertebral Rotation (AVR) is a significant indicator of adolescent idiopathic scoliosis (AIS). A host of methods are provided to measure AVR on coronal plane radiographs or 3D vertebral model. This paper provides a method of automatic AVR measurement in 3D vertebral model that is based on point cloud segmentation neural network and the tip of the spinous process searching algorithm. An improved PointNet using multi-input and attention mechanism named Multi-Input PointNet is proposed, which can segment the upper and lower endplates of the vertebral model accurately to determine the transverse plane of vertebral model. An algorithm is developed to search the tip of the spinous process according to the special structure of vertebrae. AVR angle is measured automatically using the midline of vertebral model and projection ofy-axis on the transverse plane of vertebral model based on points obtained above. We compare automatic measurement results with manual measurement results on different vertebral models. The experiment shows that automatic results can achieve accuracy of manual measurement results and the correlation coefficient of them is 0.986, proving our automatic AVR measurement method performs well.

Fabrication of pure chitosan nanofibrous membranes as effective absorbent for dye removal.

The pure chitosan nanofibrous membranes with average fiber diameter of 86±18, 114±17,164±28nm were successfully prepared by electrospinning. Batch adsorption experiments of using chitosan nanofibrous membranes as adsorbent to remove acid blue-113 were conducted. The adsorption capacity of 1377mg/g was achieved by the chitosan nanofibrous membrane with average fiber diameter of 86nm, which was superior to the chitosan microscale sample with the adsorption capacity of 412mg/g. The average fiber diameter and the corresponding equilibrium adsorption capacity of pure chitosan nanofibrous membranes fitted well with linear relationship in our test range. The results also showed that the adsorption followed with pseudo second-order kinetics model, and the adsorption behavior was accordance with the Langmuir isotherm model. The pure chitosan nanofibrous membrane showed promise and feasibility as an effective adsorbent for dye removal.

Synthesis and flocculation performance of a chitosan-acrylamide-fulvic acid ternary copolymer.

The flocculant made from natural polymers gained prominence in recent years due to its eco-friendliness and low cost. In this study, two natural polymers of chitosan and fulvic acid were successfully grafted with a synthetic monomer of acrylamide as a new type of flocculant. The prepared chitosan-acrylamide-fulvic acid (CAMFA) exhibited an excellent capacity to remove three typical dyes, the color removal ratios were 97.0%, 91.6%, and 38.2%, respectively, at the dosage of 283mg/L for 100mg/L of acid blue 113, reactive black 5 and methyl orange. The main flocculation mechanisms were charge neutralization and bridging effect. CAMFA showed nice flocculation performance with solubility in pure water, high removal efficiency, broad pH effectiveness scope, and a wide flocculation window. The ternary copolymer based on natural polymers is a promising candidate as a flocculant from the perspective of effectiveness, operation simplicity and cost.

The effect of fiber size and pore size on cell proliferation and infiltration in PLLA scaffolds on bone tissue engineering.

The scaffold microstructure has a great impact on cell functions in tissue engineering. Herein, the PLLA scaffolds with hierarchical fiber size and pore size were successfully fabricated by thermal-induced phase separation or combined thermal-induced phase separation and salt leaching methods. The PLLA scaffolds were fabricated as microfibrous scaffolds, microfibrous scaffolds with macropores (50-350 µm), nanofibrous scaffolds with micropores (100 nm to 10 µm), and nanofibrous scaffolds with both macropores and micropores by tailoring selective solvents for forming different fiber size and pre-sieved salts for creating controlled pore size. Among the four kinds of PLLA scaffolds, the nanofibrous scaffolds with both macropores and micropores provided a favorable microenvironment for protein adsorption, cell proliferation, and cell infiltration. The results further confirmed the significance of fiber size and pore size on the biological properties, and a scaffold with both micropores and macropores, and a nanofibrous matrix might have promising applications in bone tissue engineering.