BACKGROUND:Currently,pedicle screw fixation technology is recognized as the gold standard for lumbar posterior fusion surgery.However,this technique is associated with several complications such as suboptimal screw placement,loosening,and fracture.Addressing these issues,it requires a thorough investigation into the mechanical properties of screw reinsertion to optimize surgical procedures and enhance success rates and safety.OBJECTIVE:By combining finite element analysis with biomechanical experiments,this study aims to compare and analyze the mechanical performance of traditional trajectory pedicle screws during multiple extraction processes.The goal is to reveal patterns in screw extraction strength over repeated withdrawals,providing scientific insights into the safety and effectiveness of pedicle screw reinsertion for clinicians.METHODS:Based on CT scan data,a three-dimensional reconstruction of the L4 vertebra model was performed.Three-dimensional printing technology was used to create biological experimental samples.A pull-out experiment was conducted according to a screw placement plan.Utilizing CT data and standard pedicle screw parameters,a finite element model of the L4 vertebra and a pedicle screw model(diameter 6.0 mm,length 45 mm)were established.The model was divided into five operating conditions based on screw placement angle and cycles.A finite element model was developed to simulate axial pull-out testing,analyzing stress distribution in the vertebral body and maximum axial pull-out strength of the screw.Mechanics experimental results of three-dimensional printing were compared and analyzed against simulation outcomes.RESULTS AND CONCLUSION:(1)A dedicated experimental setup for pedicle screw extraction from single vertebrae was designed and constructed.(2)In the three-dimensional printing experiment,our groups of models were compared between correctly placed screws and once improperly placed screws.The correctly placed screws group exhibited a maximum pull-out force of(1 422.63±23.80)N.Furthermore,with increasing deviation angles in screw placement,the maximum pull-out forces of each group gradually decreased.(3)Comparing the condition of a single improper nail placement with repositioning the nail correctly,when the offset angle of the improper placement exceeded that of Model 3,correctly repositioning the nail helps to increase the screw's pull-out resistance.(4)Comparing the scenario of two consecutive improper nail placements with repositioning correctly after two improper placements,correctly repositioning the nail reduced the screw's pull-out resistance.Without replacing the screw,it was not advisable to attempt a third nail placement.(5)Experimental pull-out strength of three-dimensional printing correlates significantly with finite element simulation results,with a correlation coefficient of 0.98.There is no significant difference in the outcomes between the two methods(P＞0.05).

BACKGROUND:Currently,pedicle screw fixation technology is recognized as the gold standard for lumbar posterior fusion surgery.However,this technique is associated with several complications such as suboptimal screw placement,loosening,and fracture.Addressing these issues,it requires a thorough investigation into the mechanical properties of screw reinsertion to optimize surgical procedures and enhance success rates and safety.OBJECTIVE:By combining finite element analysis with biomechanical experiments,this study aims to compare and analyze the mechanical performance of traditional trajectory pedicle screws during multiple extraction processes.The goal is to reveal patterns in screw extraction strength over repeated withdrawals,providing scientific insights into the safety and effectiveness of pedicle screw reinsertion for clinicians.METHODS:Based on CT scan data,a three-dimensional reconstruction of the L4 vertebra model was performed.Three-dimensional printing technology was used to create biological experimental samples.A pull-out experiment was conducted according to a screw placement plan.Utilizing CT data and standard pedicle screw parameters,a finite element model of the L4 vertebra and a pedicle screw model(diameter 6.0 mm,length 45 mm)were established.The model was divided into five operating conditions based on screw placement angle and cycles.A finite element model was developed to simulate axial pull-out testing,analyzing stress distribution in the vertebral body and maximum axial pull-out strength of the screw.Mechanics experimental results of three-dimensional printing were compared and analyzed against simulation outcomes.RESULTS AND CONCLUSION:(1)A dedicated experimental setup for pedicle screw extraction from single vertebrae was designed and constructed.(2)In the three-dimensional printing experiment,our groups of models were compared between correctly placed screws and once improperly placed screws.The correctly placed screws group exhibited a maximum pull-out force of(1 422.63±23.80)N.Furthermore,with increasing deviation angles in screw placement,the maximum pull-out forces of each group gradually decreased.(3)Comparing the condition of a single improper nail placement with repositioning the nail correctly,when the offset angle of the improper placement exceeded that of Model 3,correctly repositioning the nail helps to increase the screw's pull-out resistance.(4)Comparing the scenario of two consecutive improper nail placements with repositioning correctly after two improper placements,correctly repositioning the nail reduced the screw's pull-out resistance.Without replacing the screw,it was not advisable to attempt a third nail placement.(5)Experimental pull-out strength of three-dimensional printing correlates significantly with finite element simulation results,with a correlation coefficient of 0.98.There is no significant difference in the outcomes between the two methods(P＞0.05).

The setting and adjustment of ventilator parameters need to rely on a large amount of clinical data and rich experience. This paper explored the problem of difficult decision-making of ventilator parameters due to the time-varying and sudden changes of clinical patient's state, and proposed an expert knowledge-based strategies for ventilator parameter setting and stepless adaptive adjustment based on fuzzy control rule and neural network. Based on the method and the real-time physiological state of clinical patients, we generated a mechanical ventilation decision-making solution set with continuity and smoothness, and automatically provided explicit parameter adjustment suggestions to medical personnel. This method can solve the problems of low control precision and poor dynamic quality of the ventilator's stepwise adjustment, handle multi-input control decision problems more rationally, and improve ventilation comfort for patients.
Humans ; Ventilators, Mechanical ; Respiration, Artificial ; Neural Networks, Computer

Objective: To explore the night sleep quality of shift nurses and the current situation of their daytime tiredness, sleepiness, and to provide evidence for nursing administrators and managers to allocate human resources reasonably and prevent adverse events. Methods: The cross-sectional method was utilized to conduct a questionnaire survey among shift nurses in a tertiary teaching hospital in Shandong Province from March to May inclusive, 2017. Results: There was a total of 233 valid questionnaires returned. The prevalence of sleep disorder, daytime tiredness and sleepiness was 45.92%, 16.31% and 13.30%, respectively. The differences of the nurses' sleep quality at night between different ages, marriages, educational backgrounds and professional titles were statistically significant (P<0.05) , while the differences of daytime burnout and sleep state between different shift systems were statistically significant (P<0.01) . Night sleep quality was positively correlated with daytime tiredness and sleepiness (P<0.05) . The results of multiple linear regression analysis showed that age, marriage, educational background and professional title had an impact on nurses' sleep quality at night (P<0.05) . Shift system had an impact on nurses' daytime burnout and sleep apnea (P<0.01) . Conclusion There was a high prevalence of night sleep disorder, daytime tiredness and sleepiness among the shift nurses. Nursing administrators and managers should pay more attention to the night sleep quality of nurses who aged over 30 years old, married, without a bachelor degree and those with a lower professional rank. Furthermore, the current situation of daytime tiredness and sleepiness among two-shift only nurses was worrisome.

Objective To investigate the circulation and use of Akebiae Caulis and Clematidis Armandii Caulis;To provide references for clinical safe medication. Methods Literature review, field survey and telephone interview were used to conduct the investigation. Results ① The market currency of the Akebiae Caulis and Clematidis Armandii Caulis was very confused, and the mainly medicinal materials on the market were Clematidis Armandii Caulis. ② The majority used medicinal materials were Clematidis Armandii Caulis, and Akebiae Caulis was rarely used. ③ The Chinese Pharmacopoeia collected Akebiae Caulis and Clematidis Armandii Caulis separately, but there was phenomenon of using Clematidis Armandii Caulis replacing of Akebiae Caulis. Conclusion Market of Akebiae Caulis is shrinking; the phenomenon of using Clematidis Armandii Caulis to replace Akebiae Caulis widespread in clinic. There are differences in the efficacy of Akebiae Caulis and Clematidis Armandii Caulis, so they should be distinguished and cannot be used to mix or substitute.

Through detailed investigation of the market circulation of Ligustici Rhizoma et Radix, at the same time, this article collected relevant articles, conducted comparative study on genuine and conventionally used Ligustici Rhizoma et Radix from the aspects of textual research, functions, chemical composition and pharmacological effect, and discussed the results of the study.