Objective Based on multi-objective optimization,a design method for Voronoi bionic porous scaffolds tailored to different degrees of bone defects was proposed.Methods First,the effects of design parameters on mechanical and biological properties of the scaffolds were investigated.The response surface models were then established respectively for the design parameters and performance indicators(specific surface area,elastic modulus,yield strength,and permeability).Using a cubic scaffold with side length of 15 mm as an example(assuming a corresponding bone defect of the same dimension),multi-objective optimization of the scaffold was finally conducted using the non-dominated genetic algorithm-Ⅱ algorithm,while considering the elastic modulus and permeability ranges of bone tissues as performance constraints.Results The degree of anisotropy in Voronoi scaffolds was influenced by the number of seed points,while the size and scaling factors of the scaffolds exclusively impacted the rod diameter and rod length.Using the design method of this study,the optimal scaffold with specific defect size satisfying mechanical and biological properties was designed.The optimal scaffold meeting different strength requirements was designed by adjusting the yield strength to change the utopia point.Conclusions A design method for Voronoi bionic porous scaffolds based on multi-objective optimization is proposed.This method can be applied to bone defects at varying degrees and provides a new idea for the personalized design of bone tissue engineering scaffolds.

Objective Based on multi-objective optimization,a design method for Voronoi bionic porous scaffolds tailored to different degrees of bone defects was proposed.Methods First,the effects of design parameters on mechanical and biological properties of the scaffolds were investigated.The response surface models were then established respectively for the design parameters and performance indicators(specific surface area,elastic modulus,yield strength,and permeability).Using a cubic scaffold with side length of 15 mm as an example(assuming a corresponding bone defect of the same dimension),multi-objective optimization of the scaffold was finally conducted using the non-dominated genetic algorithm-Ⅱ algorithm,while considering the elastic modulus and permeability ranges of bone tissues as performance constraints.Results The degree of anisotropy in Voronoi scaffolds was influenced by the number of seed points,while the size and scaling factors of the scaffolds exclusively impacted the rod diameter and rod length.Using the design method of this study,the optimal scaffold with specific defect size satisfying mechanical and biological properties was designed.The optimal scaffold meeting different strength requirements was designed by adjusting the yield strength to change the utopia point.Conclusions A design method for Voronoi bionic porous scaffolds based on multi-objective optimization is proposed.This method can be applied to bone defects at varying degrees and provides a new idea for the personalized design of bone tissue engineering scaffolds.

This study overviewed equivalence demonstration, the principles for the selection of comparative devices, the difficulties in equivalence demonstration, and the equivalence demonstration of special medical devices. In addition, the concept of equivalence demonstration was adopted for the products exempted from clinical evaluation, and there were many confusion in actual use. The operation points and difficult points of equivalence demonstration for the products exempted from clinical evaluation were introduced in order to provide reference for medical device colleagues.

In order to establish a bone scaffold with good biological properties, two kinds of new gradient triply periodic minimal surfaces (TPMS) scaffolds, i.e., two-way linear gradient G scaffolds (L-G) and D, G fusion scaffold (N-G) were designed based on the gyroid (G) and diamond (D)-type TPMS in this study. The structural mechanical parameters of the two kinds of scaffolds were obtained through the compressive simulation. The flow property parameters were also obtained through the computational fluid dynamics (CFD) simulation in this study, and the permeability of the two kinds of scaffolds were calculated by Darcy's law. The tissue differentiation areas of the two kinds of scaffolds were calculated based on the tissue differentiation theory. The results show that L-G scaffold has a better mechanical property than the N-G scaffold. However, N-G scaffold is better than the L-G scaffold in biological properties such as permeability and cartilage differentiation areas. The modeling processes of L-G and N-G scaffolds provide a new insight for the design of bone scaffold. The simulation in this study can also give reference for the prediction of osseointegration after the implantation of scaffold in the human body.
Bone and Bones ; Humans ; Permeability ; Porosity ; Tissue Engineering ; Tissue Scaffolds

OBJECTIVE: To build up a simple and effective comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. METHOD: One hundred and twenty cases of laryngeal tubor were selected. Using Logistic regression method to analyse relative factors, including weight, height, BMI, neck girth, neck upward degree, upper-lower incisor teeth distance, thyroid-mentum distance, thyroid-sternum distance, Mallampati test, Yamamoto test and Upper lip bite test. Build data-base to construct a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. RESULT: The relative factors of difficult laryngeal exposure were BMI, neck girth, upper-lower incisor teeth distance, neck upward degree, thyroid-mentum distance, Mallampati test and Yamamoto test (P < 0.05). To build up a comprehensive system for predicting difficult laryngeal exposure under suspension laryngoscopy. The predicting standards included the seven relative factors, each factor has 1 score, 2 score, 3 score. Higher score means more risk. Eight score was designed as minimum, under the premise,the sensibility, misdiagnosis rate, missed misdiagnosis rate, specificity of the experiment were 95.5%, 5.3%, 4.5%, 94.7%. CONCLUSION The comprehesive system is an effective method for predicting difficult intubation. It can help to identify difficult cases according to the results of this predicting system.
Anthropometry ; Chin ; Humans ; Intubation, Intratracheal ; methods ; Laryngoscopy ; methods ; Larynx ; Lip ; Neck ; Thyroid Gland