Background: To investigate directional deviations between pilot holes and final pedicle screw trajectories in freehand placement and analyze risk factors for misplacement. While pedicle screws are widely used in thoracolumbosacral surgery, directional deviations between pilot holes and final screw trajectories remain understudied as potential risk factors for misplacement. Methods: Thirty-three patients undergoing posterior fixation were prospectively enrolled. Inertial measurement units (IMUs) tracked the spatial positions of pedicle finders and screwdrivers via custom software. Surgeons (n = 6) were stratified into senior, middle, and junior groups. Analyzed variables included the use of tapping, surgeon experience, spinal deformity status, screw tip morphology, and surgical parameters. Results: Among 198 implanted screws (6.00 ± 2.88/patient), all exhibited trajectory deviations (8.12° ± 3.47°). Tapping significantly reduced deviations (7.23° ± 3.23° vs. 8.87° ± 3.31°, p < 0.01). Senior surgeons achieved smaller deviations (7.34° ± 3.33°) than the middle group (8.60° ± 3.51°, p = 0.039) and junior group (8.68° ± 3.49°, p = 0.022). Multivariate analysis confirmed tapping (p = 0.001) and senior experience (p = 0.023) as protective factors. No significant associations emerged for spinal deformity (8.43° ± 3.73° vs. 7.97° ± 3.35°, p = 0.377), screw tip type (cylindrical, 8.43° ± 3.26° vs. tapered, 8.07 ± 3.51°; p = 0.637), obesity, or surgical position parameters. Conclusions Freehand pedicle screw placement consistently produces trajectory deviations from pilot holes, and surgeon experience and tapping are modifiable protective factors. The IMU-based tracking system enables quantitative surgical motion analysis, suggesting its utility for training optimization and technique standardization.

Objective To systematically review the sex differences in efficacy of immune checkpoint inhibitors (ICIs) for non-small cell lung cancer (NSCLC) patients. Methods We conducted a computer search of Medline, The Cochrane Library, and EMbase from inception to November 2022 to identify randomized controlled trials (RCTs) assessing the efficacy of ICIs in patients with NSCLC. A meta-analysis was performed using RevMan 5.4 software. Results Finally 16 RCTs with a total of 9 653 patients were included, and the modified Jadad scale score was≥4 points. Meta-analysis results showed that in female NSCLC patients receiving immune therapy, the median overall survival (OS) [HR=0.72, 95%CI (0.61, 0.85), P<0.001] was longer than that in males [HR=0.73, 95%CI (0.69, 0.78), P<0.001]. Males [HR=0.64, 95%CI (0.58, 0.71), P<0.001] had an advantage over females [HR=0.76, 95%CI (0.57, 1.03), P=0.760] in median progression-free survival (PFS). Conclusion Females receiving ICIs have an advantage over males in terms of median OS. However, males tend to derive greater benefit from ICIs in terms of median PFS.

Porcine reproductive and respiratory syndrome virus(PRRSV)mainly causes sow abor-tion,stillbirth,mummified fetus and respiratory symptoms in piglets.Since first reported in China in 1996,the virus complexity has increased significantly in more than 20 years of genetic evolution,bringing huge economic losses to the pig industry.In recent years,with the emergence of various PRRSV recombinant virus strains,preventing and controlling this epidemic became increasingly difficult.The purpose of this article is to comprehensively review the genome structure and func-tion of PRRSV,RNA virus recombination mechanism,main types of recombination,and the epi-demic status and recombination for the dominant epidemic PRRSV strains,in order to provide clues for in-depth research on gene recombination of PRRSV,thus providing the theoretical sup-port for formulating scientific prevention and control strategies.

Porcine reproductive and respiratory syndrome virus(PRRSV)mainly causes sow abor-tion,stillbirth,mummified fetus and respiratory symptoms in piglets.Since first reported in China in 1996,the virus complexity has increased significantly in more than 20 years of genetic evolution,bringing huge economic losses to the pig industry.In recent years,with the emergence of various PRRSV recombinant virus strains,preventing and controlling this epidemic became increasingly difficult.The purpose of this article is to comprehensively review the genome structure and func-tion of PRRSV,RNA virus recombination mechanism,main types of recombination,and the epi-demic status and recombination for the dominant epidemic PRRSV strains,in order to provide clues for in-depth research on gene recombination of PRRSV,thus providing the theoretical sup-port for formulating scientific prevention and control strategies.

The study was carried out to understand the changes in the ethical cognition status of laboratory animals and the effectiveness of laboratory animal ethics education among medical students in Xiangya School of Medicine of Central South University (CSU), and provide new enlightenment for further strengthening the ethical education of laboratory animals. In the study, the same self-compiled questionnaire was used to investigate the ethical cognition of experimental animals among medical students in Xiangya School of Medicine of CSU in 2011 and 2021, and 359 and 363 questionnaires were collected respectively. Through comparative analysis of the questionnaire results before and after ten years, it was found that medical students’ animal experiment operation and attitudes towards laboratory animals, cognition of experimental animal ethics knowledge and their attitude to animal experiment ethics education were significantly improved. It showed that the state of experimental animal ethics cognition among medical students in Xiangya School of Medicine of CSU had improved significantly in recent 10 years, but the cognition of experimental animal ethics knowledge was higher than the actual behavior of caring for experimental animals, and there was the phenomenon of "separation of knowledge and action". The ethics education of experimental animals needs to pay more attention to the development of students’ behavior of caring for experimental animals.

Objective:To investigate the interactive effect of mismatch repair (MMR) protein status and adverse clinicopathological features on prognosis of stage Ⅰ-Ⅲ colon cancer.Methods:The retrospective cohort study was conducted. The clinicopathological data of 1 650 patients with colon cancer of stage Ⅰ-Ⅲ who were admitted to 7 hospitals in China from January 2016 to December 2017 were collected. There were 963 males and 687 females, aged 62(53,71)years. Patients were classified as 230 cases of MMR deficiency (dMMR) and 1 420 cases of MMR proficiency (pMMR) based on their MMR protein status. Observation indicators: (1) comparison of clinicopathological characteristics between patients of different MMR protein status; (2) analysis of factors affecting the survival outcomes of patients of dMMR; (3) analysis of factors affecting the survival outcomes of patients of pMMR; (4) interaction analysis of MMR and adverse clinicopathological features on survival outcomes. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the Mann-Whitney U test. Count data were described as absolute numbers, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data was conducted using the Mann-Whitney U test. The random forest interpolation method was used for missing values in data interpolation. Univariate analysis was conducted using the COX proportional risk regression model, and multivariate analysis was conducted using the COX stepwise regression with forward method. The coefficient of multiplication interaction effect was obtained using the interaction term coefficient of COX proportional risk regression model. Evaluation of additive interaction effects was conducted using the relative excess risk due to interaction ( RERI). Results:(1) Comparison of clinicopathological characteristics between patients of different MMR protein status. There were significant differences in age, T staging, the number of lymph node harvest, the number of lymph node harvest <12, high grade tumor between patients of dMMR and pMMR ( P<0.05). (2) Analysis of factors affecting the survival outcomes of patients of dMMR. Results of multivariate analysis showed that T staging, N staging, the number of lymph node harvest <12 were independent factors affecting the disease-free survival (DFS) of colon cancer patients of dMMR ( hazard ratio=3.548, 2.589, 6.702, 95% confidence interval as 1.460-8.620, 1.064-6.301, 1.886-23.813, P<0.05). Age and N staging were independent factors affecting the overall survival (OS) of colon cancer patients of dMMR ( hazard ratio=1.073, 10.684, 95% confidence interval as 1.021-1.126, 2.311-49.404, P<0.05). (3) Analysis of factors affecting the survival outcomes of patients of pMMR. Results of multivariate analysis showed that age, T staging, N staging, vascular tumor thrombus were independent factors affecting the DFS of colon cancer patients of pMMR ( hazard ratio=1.018, 2.214, 2.598, 1.549, 95% confidence interval as 1.006-1.030, 1.618-3.030, 1.921-3.513, 1.118-2.147, P<0.05). Age, T staging, N staging, high grade tumor were independent factors affecting the OS of colon cancer patients of pMMR ( hazard ratio=1.036, 2.080, 2.591, 1.615, 95% confidence interval as 1.020-1.052, 1.407-3.075, 1.791-3.748, 1.114-2.341, P<0.05). (4) Interaction analysis of MMR and adverse clinicopathological features on survival outcomes. Results of interaction analysis showed that the multiplication interaction effect between the number of lymph node harvest <12 and MMR protein status was significant on DFS of colon cancer patients ( hazard ratio=3.923, 95% confidence interval as 1.057-14.555, P<0.05). The additive interaction effects between age and MMR protein status, between high grade tumor and MMR protein status were significant on OS of colon cancer patients ( RERI=-0.033, -1.304, 95% confidence interval as -0.049 to -0.018, -2.462 to -0.146). Conclusions:There is an interaction between the MMR protein status and the adverse clinicopathological features (the number of lymph node harvest <12, high grade tumor) on prognosis of colon cancer patients of stage Ⅰ-Ⅲ. In patients of dMMR, the number of lymph node harvest <12 has a stronger predictive effect on poor prognosis. In patients of pMMR, the high grade tumor has a stronger predictive effect on poor prognosis.

Objective:To compare the self-evaluated learning behavior and achievement of eight-year-program clinical medical students on online and offline problem-based learning (PBL), and to provide references and suggestions for successful implementation of online PBL teaching.Methods:During the three semesters of September 2020 to January 2022, a survey was performed on 100 clinical medical students of 2018 eight-year program on online or offline PBL teaching in Xiangya School of Medicine, Central South University. At the end of PBL courses, the students received questionnaires to self-assess their learning behavior and achievement in online or offline PBL teaching. The data were analyzed using the paired rank sum test with the use of SPSS 26.0.Results:Before class, there were no significant differences in learning behaviors including preparation time, communication with classmates, and materials collecting and sorting between students on online and offline PBL teaching ( P>0.05). In class, no significant differences were found in students' initiative of speaking and degree of satisfaction with classmates' speaking between online and offline teaching ( P>0.05), but the students on offline teaching showed significantly better concentration of attention ( Z=-4.24, P<0.001), listening to classmates' speeches ( Z=-3.42, P=0.001), and classmates' interaction ( Z=-3.11, P=0.002) compared with those on online teaching. No significant differences were observed between online and offline PBL teaching in students' self-evaluated learning achievements including improvements in autonomous learning ability, problem-solving ability, and literature inquiry skills ( P>0.05). Conclusion:Students on online PBL teaching have generally as good pre-class preparation and in-class learning performance as those on offline PBL teaching, indicating that the online PBL mode can be well implemented, and it can also ensure almost the same learning achievement as offline teaching.

Objective:To explore the detection and segmentation of ischemic core infarct volume of the acute stroke in diffusion weighted imaging (DWI) images using cascaded VB-Net.Methods:MRI data of 1 500 patients (2 456 lesions) with acute ischemic stroke in Henan Provincial People′s Hospital from December 2016 to December 2018 were retrospectively analyzed. Firstly, manual segmentation of ischemic core was performed on DWI images (b=1 000 s/mm 2), and then all data were divided into training set, validation set and independent test set by 8∶1∶1. Then, the cascaded VB-Net was constructed, and the core infarct was automatically detected and segmented in the test set. Interclass correlation coefficient (ICC) was used to evaluate the consistency of volume size measured by manual segmentation and cascaded VB-Net. The patients were divided into large ischemic core lesion group (ischemic core volume ≥10 ml) and small ischemic core lesion group (ischemic core volume<10 ml), and the Dice coefficient difference between the two groups was compared using Mann-Whitney U test. Results:In independent test set, cascaded model had the detection rate of 94.6% (243/257) with Dice coefficient of 0.76 (0.68, 0.84). The agreement of cacade VB-Net segmented [4.19(1.21,14.13)ml] and manual segmented ischemic core infarct volume [4.08(1.19,17.92)ml] was high (ICC=0.97, P<0.001). There was no significant difference in Dice coefficient between large and small lesion groups [0.76 (0.69, 0.85), 0.76 (0.67, 0.84), Z=-0.44, P=0.657]. Conclusions:The cascaded VB-Net model provided a tool to realize automatic detection, segmentation, and calculation of ischemic core infarct volume. It has good segmentation accuracy and high consistency with manual segmentation, which can provide an auxiliary decision-making tool for the selection of treatment plans.

Objective:To analyze the online learning behaviors and learning results of students under different teaching modes with different learning motivations, and to provide a reference for optimizing the development of online teaching.Methods:Samples of students taking the physiology small private online course (SPOC) in 2019 and 2020, and students taking the massive open online courses (MOOC) in the same year were selected in the study to discuss the differences in learning behaviors of students under different teaching modes and learning effects on students with different learning motivations. The online learning behaviors of students were analyzed based on their learning engagement, interactive behavior and learning motivation. SPSS 25.0 was used to analyze the data with statistical methods such as function calculation, frequency statistics, regression analysis, rank sum test, correlation test and chi-square test.Results:The learning participation level ( z=14.36, P<0.001), and the human-machine and interpersonal learning interaction level ( z=-11.70, -16.18, both P<0.001) of SPOC learners in 2020 were higher than those in 2019. The overall interactive level was moderately correlated with performances of students ( r=0.42, 0.52, both P<0.001), and the correlation between interpersonal behavior and grades was much more stronger ( r=0.60, 0.55, both P<0.001). The performance composition of SPOC and MOOC learners in 2019 was completely different ( χ2=857.45, P<0.001). The learning effect of externally motivated students was significantly better than that of internally motivated students ( z=-28.42, P<0.001). Conclusion:The teaching mode adopted by the school can affect the learning effect by influencing the students' online learning engagement and interactive behavior. Besides, students' own learning motivation also plays a key role in their academic performance.

Objective:To evaluate the teaching effectiveness of independent experimental design from students' active learning behavior, and further provide the basis for advancing the reform of functional experimental teaching and teaching quality.Methods:In June 2019, 186 undergraduates (5-year-programme and 8-year-programme) of Xiangya School of Medicine were included in the teaching research. Self-administered questionnaires were applied to characterize students' active learning behavior in independent experimental design education. Spearman rank correlation analysis and Logistic regression analysis were used in the study. SPSS 23.0 was used for descriptive analysis of the data.Results:During the independent experimental design, 85.0%(158/186) of the students thought it was necessary and important to conduct independent experimental design education; 72.6%(135/186) of the students tentatively raised new scientific questions; 97.8%(182/186) of the students actively searched literature; 77.4%(144/186) of the students participated in reply positively. The value of correlation coefficient of actively learning behavior "tentatively raising new science questions" and teaching effectiveness "improving the ability of scientific thinking" was 0.81. And only 42.5%(79/186) of the students agreed that students needed to summarize after reporting.Conclusion:Independent experimental design education is welcomed and widely accepted by students, which has effectively improved the capacity for scientific research and innovation spirit of students. Whether students' active learning behavior can be fully mobilized in the education practice is closely related to the teaching effect. And the cultivation of leadership and leading consciousness still need to be improved.