Suchergebnisse

Abstract
Background Retroperitoneal schwannomas are rare. The purpose of this study was to present our experience with the diagnosis and treatment of 67 such tumors.
Methods We retrospectively analyzed 67 patients with retroperitoneal schwannoma admitted to the Peking University International Hospital from 2015 to 2021.
Results Thirty-seven of the 67 patients had no obvious clinical symptoms. Complete excision was obtained in 62 and subtotal excision in 5 cases. In7 cases, tumor resection was combined with organ resection. The intraoperative blood loss was 300 ml (20–9,000 ml), the maximum size of the tumor was 9 cm (2.5–26 cm), and postoperative complication occurred in six cases (9.0%). Compared with abdominal retroperitoneal tumors, pelvic retroperitoneal tumors had larger tumor volume, more bleeding, higher proportion of block resection, and longer postoperative hospitalization time (p < 0.05). The residual mass progressed slowly in five patients with subtotal resection, and no obvious malignant transformation occurred.
Conclusion Complete resection of a retroperitoneal schwannoma can achieve a good long-term prognosis. Residual tumor after surgery progresses slowly and rarely become malignant. We recommend early resection after the discovery of a pelvic retroperitoneal schwannoma.

There are two main approaches to motion control on parallel platforms: joint space control and workspace control. Joint space control is an easy-to-implement semi-closed-loop strategy, but its control effect could be better. The workspace control is to obtain the real-time position of the parallel platform through the forward solution and close the speed and position loop of the parallel platform in the workspace. This paper uses a Model Predictive Controller (MPC) to control the parallel platform with workspace control as the research goal. The loss function is constructed based on the swarm intelligence optimization idea, and the adaptive difference algorithm is used to optimize the parameters of MPC. This part uses MATLAB to perform simulation experiments to complete the S-shaped velocity trajectory planning algorithm. In addition, the control effect of MPC and position-loop PI controller in a robust disturbance environment is compared. Experiments show that MPC has the advantages of low energy consumption and high control accuracy.

There are two main approaches to motion control on parallel platforms: joint space control and workspace control. Joint space control is an easy-to-implement semi-closed-loop strategy, but its control effect could be better. The workspace control is to obtain the real-time position of the parallel platform through the forward solution and close the speed and position loop of the parallel platform in the workspace. This paper uses a model predictive controller (MPC) to control the parallel platform with workspace control as the research goal. The loss function is constructed based on the swarm intelligence optimization idea, and the adaptive difference algorithm is used to optimize the parameters of MPC. This part details the research background and the algorithm design process. Then, the MPC algorithm is implemented on the upper computer using C++, and the physical test is implemented. The test results show that the controller has a good control effect on the physical platform.

Background: Few studies have examined whether social support contributes to better consequences among chronic patients with severe mental illnesses (SMI) in their community recovery stage and whether self-stigma would be a mechanism through which social support impacts psychiatric symptoms and personal and social functioning. Aims: This study aimed to examine prospective associations of social support with long-term self-stigma, psychiatric symptoms, and personal and social functioning, and to investigate whether self-stigma would mediate the associations of social support with psychiatric symptoms and personal and social functioning among patients with SMI. Methods: A total of 312 persons with SMI (schizophrenia and bipolar disorder) in their community recovery stage participated in the study. Social support, self-stigma, psychiatric symptoms, and personal and social functioning were evaluated at baseline. The follow-up assessment was conducted at 6 months with the baseline measures except for social support. Hierarchical linear regression and mediation analysis were performed. Results: The results showed that baseline social support predicted decreases in stigma (β = −.115, p = .029) and psychiatric symptoms (β = −.193, p < .001), and increases in personal and social functioning (β = .134, p = .008) over 6 months, after adjusting for relevant covariates. Stigma at 6 months partially mediated the association between baseline social support and 6-month psychiatric symptoms (indirect effect: β = −.043, CI [−0.074, −0.018]). Stigma and psychiatric symptoms at 6 months together mediated the association between baseline social support and 6-month personal and social functioning (indirect effect: β = .084, 95% CI [0.029, 0.143]). Conclusion: It is necessary to provide comprehensive social support services and stigma reduction interventions at the community level to improve the prognosis of SMI.