Objective:To investigate the influences of material properties and damping effect on the dynamic response analysis of human periodontal ligament. Methods: A 3-D finite element model of human teeth and periodontal tissue was built from graphic information obtained by CT scanning. Dynamic analysis was performed to investigate the influence of different damping effects on the stresses of periodontal ligament by the finite element method. Results: (a) No significant difference of stress between small and large deformation assumption was found, the variation was no more than 1.4%.(b) Dynamic response was obtained under ? varies from 0 to 1.2. After one mastication period, the residual stress at interior surface was larger than that at exterior surface, with a maximum value of ? r = 0.34 MPa at labial cervical area. Conclusion: Appropriate assumptions on material properties may reduce the cost of analysis. After one mastication period, some levels of residual stresses are in periodontal ligament and influenced by material damp.

Objective To find out a reference range of epidermal nerve fiber density in normal humans and compare the concordance between clinical features, electrophysiology and the results of skin biopsy. Methods Fifty-one patients with peripheral neuropathy and 10 normal controls were studied. Skin biopsies were obtained from distal leg and/or proximal leg and nerves identified using immunohistochemistry with antibody against protein gene product (PGP) 9. 5. Forty-one in 51 performed routine nerve conduction vdocity and electromyography, 21 in 51 performed sympathetic skin response(SSR). The concordance of the consequences was compared. Results Intraepidermal nerve fiber density (IENFD) was (21.4 + 2. 7) /mm in thigh and (15.4±2. 2) /mm in the distal part of the leg in normal controls. IENFD was (15.0± 6. 3)/mm and (8. 1±5.9) /mm in patients. The intraepidermal nerve fiber density was significantly lower in the patients than in the normal controls both in proximal (t = 2. 976, P = 0.004) and distal legs (t= 3.191, P=0.002). Forty-eight out of 51 patients showed abnormalities in skin biopsy, among which 33 patients had length-dependent neuropathy. In the group of abnormal skin biopsy, 41 received routine electrophysiology, among which 21 (51.2%) were abnormal and they were performed SSR, turning out that 17 (81.0%) were abnormal. In 29 patients who had only small fiber neuropathy, 27(93. 1%) showed abnormalities in skin biopsy, out of whom 20 were performed routine electromyography, and it identified that 6 (30. 0%) were abnormaL In 14 receiving SSR, 11 were abnormal. Conclusion Skin biopsy is safe and tolerable, which has a higher sensitivity especially in small fiber neuropathy.

Objective To discuss the clinical diagnosis and treatment value of double-balloon enteroscopy for small intestinal bleeding diseases.Methods Retrospective collection of clinical data from 87 patients who underwent double-balloon enteroscopy for small bowel bleeding in Shantou Central Hospital from August 2019 to May 2023,and analysis of the diagnosis and treatment of small bowel bleeding causes by double-balloon enteroscopy.Results Totally 87 cases of small intestinal bleeding patients underwent a total of 117 double-balloon enteroscopy examinations,with 29 performed orally and 28 performed anally,and 30 cases simultaneously underwent both oral and anal bilateral enteroscopy examinations,with the depth of oral examination greater than that of anal examination,and the duration of oral examination shorter than that of anal examination.Among them,with a diagnostic rate of double-balloon enteroscopy at 83.91％and a pathological diagnostic accuracy rate at 83.78％.Small intestinal tumors were the main cause of small intestinal bleeding in this study,with gastrointestinal stromal tumors being the most common pathological type among small intestinal tumors.The frequency of occurrence for small intestinal tumors in individuals over 40 years old was higher than those under or equal to 40 years old group,showing statistical significance.Crohn's disease occurred more frequently in the ileum compared to jejunum,and its frequency was higher in individuals under or equal to 40 years old compared to those over 40 years old group,both differences were statistically significant(P＜0.05).A total of cases of small intestinal bleeding patients successfully underwent endoscopic hemostasis via double-balloon enteroscopy without any complications such as gastrointestinal perforation or severe bleeding during surgery.Conclusion Double balloon enteroscopy has a high diagnostic value for small intestinal bleeding and can provide basis for clinical treatment.

Objective:To systematically review the predictive model for de novo stress urinary incontinence (de novo SUI) after pelvic organ prolapse (POP) surgery, with the aim of providing reference for preventing the occurrence of de novo SUI.Methods:Literature on the prediction model of de novo SUI after POP surgery was electronically retrieved in PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure, WanFang, and VIP. The search period was from the establishment of the database to December 31, 2023, and the language was limited to Chinese and English. Two researchers independently screened literature, extracted data, and used the prediction model risk of bias assessment tool (PROBAST) to evaluate the quality of the models.Results:A total of 13 articles were included, including 13 de novo SUI risk prediction models. One literature was a prospective study, one literature was a secondary analysis of data, and the rest were retrospective studies. The area under the receiver operating characteristic curve in nine models ranged from 0.595 to 0.842, and the C-index of three models ranged from 0.710 to 0.738. Five models were not validated or only internally validated after construction. Six models were validated in one external population. The predictive performance of one model was validated in six external populations. The overall applicability of the 13 prediction models was good, but there was a certain risk of bias in all of them. Conclusions:There is a significant difference in the predictive performance of the de novo SUI risk prediction model after POP surgery, and the number is relatively small, indicating that it is still in the development stage. Future research should continuously optimize existing models and conduct external validation, and construct predictive models suitable for postoperative de novo SUI in POP patients in China.

Objective:This study aimed to introduce the technology transfer mechanism of Mayo Clinic and explore its implications for public hospitals in China.Methods:This study summarized Mayo′s technology transfer concept, management mechanism, and operation model through typical case analysis.Results:Mayo adhered to the core value of patient needs first and took it as the foundation for business operations. It practiced the operation management model of joint development of medicine, education, and research, and built a sound organizational structure, high-quality talent reserves, and a complete resource support system, which assisted in the birth of high-quality and transferable achievements.Conclusions:Public hospitals should optimize technology transfer from awareness, clinical orientation of basic research, translational medical system throughout the entire industry chain, specialized achievement transformation management team, and talent incentive mechanism.