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Background This study aimed to explore the relationship among different cervical sagittal parameters in asymptomatic volunteers and the correlation between surgical efficacy and difference of presumed and actual postoperative C2–7 Cobbs’s angle (C2–7COBB), which was calculated based on preoperative T1 slope (T1S) in patients undergoing cervical reconstruction. Methods In total, 158 inpatients with cervical spondylosis and 274 asymptomatic volunteers were retrospectively reviewed. Cervical sagittal parameters, such as C2–7COBB, T1S, thoracic inlet angle (TIA), and neck tilt (NT), were compared. Then, the correlation among these parameters was analyzed in asymptomatic volunteers, and a regression equation between T1S and C2–7COBB was established and used to analyze the correlation among the Japanese Orthopaedic Association (JOA) score improvement, the sagittal parameters, and the difference between presumed and actual postoperative C2–7COBB in patients after cervical reconstruction. Results The mean T1S, C2–7COBB, and TIA were significantly decreased in patients (P < 0.01). T1S and NT had a strong correlation with TIA (P < 0.01). T1S demonstrated a moderate correlation with C2–7COBB in asymptomatic volunteers (r = 0.569, P < 0.01). A regression equation had been established as C2–7COBB = 0.742 × T1S − 0.866. The mean C2–7COBB and JOA score improved significantly (P < 0.05) postoperatively. Moreover, the JOA improvement rate showed a significant negative correlation with the difference in the presumed and actual postoperative C2–7COBB (r = − 0.696, P < 0.01). Conclusion Our study successfully established a regression equation for calculating postsurgical C2–7COBB based on the correlation between T1S and C2–7COBB in asymptomatic volunteers. The regression equation could be used for guiding surgeons to accomplish an ideal postsurgical C2–7COBB for patients with cervical spondylosis.

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Recently, in addition to exploring the application of new saturable absorber devices in fiber lasers, soliton dynamics has also become a focus of current research. In this article, we report an ultrashort pulse fiber laser based on VSe2/GO nanocomposite and verify the formation process of soliton and soliton molecules by the numerical simulation. The prepared VSe2/GO-based device shows excellent saturable absorption characteristics with a modulation depth of 14.3% and a saturation absorption intensity of 0.93 MW/cm2. The conventional soliton is obtained with pulse width of 573 fs, which is currently the narrowest pulse width based on VSe2-related material, and has a signal-to-noise ratio of 60.4 dB. In addition, the soliton molecules are realized based on the VSe2/GO for the first time and have a pulse interval of ∼2.2 ps. We study the soliton dynamics through numerical simulation and reveal that before the formation of the soliton, it undergoes multiple nonlinear stages, such as soliton mode-locking, soliton splitting, and soliton oscillation. Furthermore, the results of numerical simulation are agreed well with the experimental data. These results indicate that the VSe2/GO might be another promising saturable absorber material for ultrafast photonics, and deepen the understanding of soliton dynamics in ultrafast fiber lasers.