Study on Preparation of Core-Spun Yarn Surgical Sutures by Compositing Drug-Loaded Nanofiber Membrane with PLA and Its Controllable Drug Release Performance

Zhichao Yang,Shuqiang Liu,Jingjing Li,Gaihong Wu,Man Zhang,Fu Li,Lu Jia,Yujing Zhang,Huimin Li,Xia Liu,Jingjing Zhao,Huiqin Zhang,Shiyu Li 한국섬유공학회 2023 Fibers and polymers Vol.24 No.12

Polylactic acid (PLA) surgical suture is considered to be one of the most ideal materials for tissue closure due to its rich raw materials and excellent biological properties. However, surgical sutures face great challenges due to problems such as wound infection and tissue reaction in practical applications. In order to improve the clinical applicability of surgical sutures, we constructed a new drug-loading system for core-spun surgical sutures. The shell was composed of nanofibrous membranes composed of polyglycolic acid (PGA) and polycaprolactone (PCL) and ciprofloxacin (CIP) antibacterial drugs, and the core layer adopts PLA filament. By adjusting the composition ratio of PGA and PCL in the shell, a new mode of regulating the release rate and release cycle of the suture was constructed. According to different wound healing time, different drug release cycles of surgical suture were selected. In the study, the structure of the core-spun yarn can be clearly observed by scanning electron microscope, the higher the shell PGA content and drug loading, the faster the drug release rate. When the carrier ratio PGA/PCL was 80/20 and the drug loading was 3%, the drug release rate was the fastest and the drug release was high; finally, antibacterial experiments showed that the suture had excellent antibacterial effect and could effectively kill Staphylococcus aureus and Escherichia coli. The successful preparation of core-spun yarn surgical suture provides a new idea for the study of new antibacterial surgical suture.

Acupotomy for Lumbar disc herniation

Chen Xilin,Fu Xinyi,Luo Zhichao,Xin Wenshan,Wang Quangui,Lee Mira,Guo Changqing 대한침구의학회 2020 대한침구의학회지 Vol.37 No.3

Background: The aim of this study was to examine whether the effects of acupotomy therapy were beneficial for the treatment of protrusion of lumbar intervertebral disc. Methods: The number of patients (n = 80) were equally assigned into treatment group and control group. Treatment group was given acupotomy therapy twice a week, and control group was given acupuncture 3 times a week, for 4 weeks. The beneficial effect and changes in score of the Japan Orthopedic Association (JOA) for low back pain were observed. Results: Among 40 cases in the treatment group, there were 25 (62.5%) with an excellent effect, 13 (32.5%) with good effect, 1 (2.5%) with a medium effect and 1 (2.5%) with poor effect, with the total experiencing an excellent/good effect of 95.0%. Among 40 cases in the control group, there were 11 (27.5%) with an excellent effect, 17 (42.5%) with good effect, 10 (25.0%) with a medium effect, and 2 (5.0%) with poor effect, with an excellent/good rate of 70.0%. The result of the rank sum test showed Z = -4.923, p < 0.05 in the comparison, indicating a significantly better outcome following acupotomy compared with acupuncture. JOA scores increased in both groups after treatment (p < 0.05), which was more significant in the acupotomy treatment group (p < 0.05). Conclusion: Acupotomy therapy has a beneficial effect on protrusion of lumbar intervertebral disc.

Dynamic Analyses and Simplified Methods for Evaluating Complicated Suspend-dome Structures Subjected to Sudden Cable Failure

Chao Zhang,Zhichao Lai,Xiaoqiang Yang,Qiang Li,Zilong Zhang,Xindi Fu 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.1

Accidental cable failure may occur for complicated suspend-dome structures, resulting in the dynamic impact effect on structures. This study presents simplified analysis methods for evaluating suspend-dome structures when sudden cable failure occurs. An implicit analysis method of improved alternative load path (IAM-IAP) was employed to simply simulate the cable failure process of the beam-string structure. The IAM-IAP was also validated by comparing the calculated results with the existing test results for the truss string structure. The parameters of the cable failure process (i.e., failure time, failure path, and damping ratio) were analyzed, and suitable values were recommended. Based on the IAM-IAP, a finite element model of multi-loop cable-string suspend-dome structure (MCSS) was established and benchmarked by verifying the static responses during construction. Dynamic responses (i.e., time histories, displacements, axial forces, and dynamic amplification factors) of MCSS were systematically investigated. The dynamic amplification factor may be larger than 2, exceeding the suggested value of existing specifications. A static equivalent method with reasonable prediction accuracy was also proposed to simply assess the dynamic responses of suspend-dome structures subjected to sudden cable failure.

Hypersonic thin plate flutter problem prediction using CFD-CSD approach

Jinan Lv,Zhichao Fu,Feng Feng,Ziqiang Liu 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.10

Hypersonic low-aspect-ratio thin plate flutter problem should be considered as a special aeroelastic case. In this paper, the flutter problem of a hypersonic thin elastic plate under Ma 6 flight condition is analyzed using CFD/CSD approach. The computed results indicate that in this case the coupling time step size should be considered cautiously but dual-time stepping and viscosity effect appears to be not significant for aeroelastic response of the thin plate.

Robustness Analysis of a Flexible Cable-Strut Tensile Structure

Lian-meng Chen,Wei-feng Gao,Zhichao Jiang,Yi-yi Zhou,Fu-bo Zhang,Shi-lin Dong 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.5

Currently, the robustness analysis of structure is primarily related to rigid structures, and little has been done to study the robustness of spatial fl exible cable-strut tensile structures with larger span, more complex forms, lower redundancy, more sensitivity to unexpected interference such as construction deviations, etc. Based on the H ∞ theory, this paper starts with the fundamental theory and develops analysis method for the robustness of fl exible cable-strut tensile structures, and then the relationships between the structural robustness and some design parameters such as initial pre-stress level, load distribution form, structural span, cross-section area, rise-span ratio, etc. are analysed through a case study of a concrete cable-strut tensile structure in China. On this basis, the eff ects of construction errors such as element-length error and supporting node position error are further analysed. Finally, the importance of each kind of element is analysed by means of conceptual removal of element. The results show that the higher the initial pre-stress level, the larger the element cross-section, the smaller the structural span, the larger the rise-span ratio and the more uniform the load distribution, the stronger the structural robustness. In the limited construction error range, the element-length error and the supporting node position error have little eff ects on the robustness of the structure. The hoop cables are the more important elements and the elements in inner region of the structure are of comparatively lower importance in the cable dome structure in this study.

Research on unsupervised condition monitoring method of pump-type machinery in nuclear power plant

Zhang Jiyu,Xia Hong,Wang Zhichao,Zhu Yihu,Fu Yin 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.6

As a typical active equipment, pump machinery is widely used in nuclear power plants. Although the mechanism of pump machinery in nuclear power plants is similar to that of conventional pumps, the safety and reliability requirements of nuclear pumps are higher in complex operating environments. Once there is significant performance degradation or failure, it may cause huge security risks and economic losses. There are many pumps mechanical parameters, and it is very important to explore the correlation between multi-dimensional variables and condition. Therefore, a condition monitoring model based on Deep Denoising Autoencoder (DDAE) is constructed in this paper. This model not only ensures low false positive rate, but also realizes early abnormal monitoring and location. In order to alleviate the influence of parameter time-varying effect on the model in long-term monitoring, this paper combined equidistant sampling strategy and DDAE model to enhance the monitoring efficiency. By using the simulation data of reactor coolant pump and the actual centrifugal pump data, the monitoring and positioning capabilities of the proposed scheme under normal and abnormal conditions were verified. This paper has important reference significance for improving the intelligent operation and maintenance efficiency of nuclear power plants