Electromagnetic tracking is a method to track the position and space attitude of objects utilizing electromagnetic field. In this paper, the main methods during the development of Electromagnetic tracking are summarized and classified according to the magnetic field generation method, the number of magnetic sources and sensors used, the configuration and geometry of them. Tracking algorithm and calibration methods are also discussed. The critical issues during the development of electromagnetic tracking are analyzed, with the hope of helping the further research and application of electromagnetic tracking.
Algorithms ; Electromagnetic Fields ; Phantoms, Imaging

This study is to evaluate the application of the comprehensive capacity assessment system based on post competence in competitive recruitment of family doctors. Thirty five general practitioners participating in the family doctor post competition in 2019—2020 were graded and ranked by both the post competition method and the comprehensive capacity assessment system of family doctors. The top 32 candidates in terms of total scores were selected as the successful candidates for the family doctor job competition. Kappa test was used to assess the consistency of competition results between the two methods. Among 32 candidates who were qualified according to the 2019—2020 family doctors post competition method, 31 (96.9%) were also qualified for the family doctor′s comprehensive capacity assessment system ( Kappa=0.635, P<0.01). The results indicate that the comprehensive capacity assessment system for family doctors based on post competency is rational and objective, and can be used for competitive recruitment of family doctors in community health service center.

Objective:To observe the image characteristics of optical coherence tomography (OCT) in patients with primary vitreoretinal lymphoma (PVRL).Methods:A retrospective clinical study. Thirty-two eyes of 19 patients diagnosed with PVRL by vitreous pathology in the Department of Ophthalmology, Beijing Tongren Hospital from September 2016 to October 2019 were included in this study. There were 7 males and 12 females. The median age was 56 years. The mean time from symptom onset to final diagnosis was 6.1±3.8 months. The first diagnosis was uveitis in 12 cases (63.1%, 12/19), retinal vein occlusion in 2 cases (10.5%, 2/19), central retinal artery occlusion in 1 case (5.3%, 1/19), and suspected PVRL of camouflage syndrome in 4 cases (21.1%, 4/19). Routine ophthalmic examination and frequency-domain OCT examination were performed in all the patients, and typical images were stored for analysis. According to the examination results, PVRL OCT signs were divided into vitreous cells, inner retinal infiltration, outer retinal infiltration, retinal pigment epithelial (RPE) infiltration, sub-RPE infiltration, and subretinal fluid.Results:Vitreous cells were found in all eyes (100.0%, 32/32). RPE infiltrated were observed in 19 eyes (59.4%, 19/32), RPE infiltration in 16 eyes (50.0%, 16/32), outer retinal infiltration in 8 eyes (25.0%, 8/32), inner retinal infiltration in 16 eyes (50.0%, 16/32), and subretinal fluid in 4 eyes (12.5%, 4/32).Conclusions:PVRL OCT signs can involve vitreous and retinal anatomical levels, including vitreous cells, inner retinal infiltration, outer retinal infiltration, RPE infiltration, sub-RPE infiltration and subretinal fluid. The same patient can show multiple signs at the same time.

Objective:To compare the effects of stromal cell-derived factor-1 (SDF-1 )and granulocyte colony-stimulating factor (G-CSF)on proliferation,migration,and odontoblastic differentiation of human dental pulp stem cell (DPSC)in vitro.Methods:DPSCs were cultured in vitro and treated with either 1 00 μg/L SDF-1 or 1 00 μg/L G-CSF.Cell counting kit-8 (CCK-8 )and colony-forming unit (CFU ) were used to detect the effect of SDF-1 and G-CSF on the proliferation ability of DPSC.Cell migration of DPSC was determined by wound healing assay and Transwell migration assay.The effects of SDF-1 and G-CSF on odontoblastic differentiation of DPSC were evaluated by alkaline phosphatase (ALP)staining, ALP activity and alizarin red S staining.The expression of odontoblastic-related genes such as dentin ma-trix protein 1 (DMP-1 )and dentin sialophosphoprotein (DSPP)were quantified by real-time RT-PCR. Results:SDF-1 and G-CSF promoted the proliferation of DPSC slightly,but the difference was not statis-tically significant.Wound healing assay showed that SDF-1 and G-CSF promoted cell migration of DPSC significantly (P<0.01 ),but there was no significant difference between the two factors.In Transwell migration assay,the number of migrated cells of the control group was 5 .0 ±1 .4 per sight,while the SDF-1 group was 24.3 ±6.8 per sight and the G-CSF group was 1 1 .8 ±3.3 per sight,suggesting that cell migration of DPSC was improved significantly after being treated with SDF-1 or G-CSF,and SDF-1 was more effective than G-CSF (P<0.05 ).Significantly greater odontoblastic differentiation potential was found in SDF-1 group and G-CSF group based on the ALP staining.Higher ALP activity,more mineralization nodule formation and higher expressions of DMP-1 and DSPP were also found after SDF-1 or G-CSF treatment.Conclusion:SDF-1 had no significant effect on the proliferation of DPSC,but could significantly promote cell migration and odontoblastic differentiation of DPSC.Its effect on DPSC was bet-ter than G-CSF.

Objective To define the assessment dimensions of community-based elderly care service.Methods Firstly 11 assessment dimensions of elderly care service needs were teased out through literature review and group discussion, these were illness, self-care ability, vision, risk of falls, willingness/information self-expression ability, the comprehension in others' willingness/information, depression, anxiety, family care ability, self-desires for old-age support, family-desires for old-age support.Then 37 experts were invited to reconfirm and empower theose assessment dimensions with two rounds of Delphi method.Results Results showed that the enthusiasm and authority degree of experts were favorable in two rounds, and the results from the second round showed strong opinion coordination.Finally, 12 assessment dimensions were confirmed, in which financial situation of the aged added and used for reference.After weight calculation, illness was weighted the highest (0.11), while vision and the degree of anxiety were weighted lowest in 11 dimensions (0.07).Conclusion The reliability of the assessment dimensions of the aged service needs is high.This study had positive significance on the solution of the dilemma in elderly care at the present stage.

Nutrition therapy is an important part of the treatment of Crohn’s disease(CD),which plays an important role in correcting malnutrition,inducing disease remission,and for the perioperative management. Nutrition therapy, especially enteral nutrition(EN),has been studied for its effect on CD. We have long been focusing on the use of nutrition therapy in the treatment of CD,especially the use of EN in the perioperative management of CD. Here,we reviewed the indications,effects,endpoints and the underlying mechanisms of preoperative nutrition therapy,through which we hope can shed light on improving the optimization of preoperative management as well as the standardization of preoperative nutrition therapy in CD.

Objective To explore the clinical effect of high intensity focused ultrasound(HIFU)combined with transcatheter arterial chemoembolization(TACE)in the treatment of primary liver cancer.Methods A total of 106 patients with primary liver cancer were divided into two groups:50 cases were treated with TACE,and the other 56 were treated with combination of HIFU and TACE.The changes of AFP levels and the size of tumors after three months treatment were analyzed and compared with each other.The survival rates for one,two and three years were calculated with Kaplan-Meier method and compared between the two groups.Results In the two groups,AFP decreased significantly after treatment,but the combined group was superior to the other in AFP decrease.In the combined group,the 1-,2-and 3-year survival rates were higher than those in the TACE group with 82.3%,60.8%and 39.2% vs 68.0%,42.6%and 21.0%respectively(P＜0.01).No serious complications were seen,such as burn of skin,bleeding,gastrointestinal perforation. Conclusion The use of HIFU combined with TACE in the treatment of patients with primary liver cancers is feasible and safe.The combined group is superior to simple TACE for the management of primary liver cancers,and the former is more effective in decreasing AFP level and improving survival rates.

Objective To determine the effects of different doses of cisatracurium on motor e-voked potential of neurosurgery operation.Methods Sixty patients,36 males and 24 females,aged 18 to 65 years,ASA physical status Ⅰ or Ⅱ,scheduled for spinal surgery with motor evoked potential monitoring,were included and randomly assigned to three groups.A single dose of cisatra-curium besilate for injection was given by intravenous injection in 5 s after the induction of general an-esthesia,respectively 0.1 mg/kg (group A),0.1 5 mg/kg (group B)and 0.2 mg/kg (group C).Cas-cade Elite 32 channel monitor was used to monitor MEPs,the electrode was stimulated for once two minutes after given the muscle relaxant,and the leading time of the wave of MEPs was recorded. Cooper’s score was used to evaluate the intubation conditions.Results The appearance time of the wave of motor evoked potentials was significantly longer in group C [(39.60±1.79)min]than that in groups A [(20.10 ± 1.89 )min]and B [(20.50 ± 1.93 )min](P < 0.05 ).The intubation conditions was significantly better in group B (100%)and C (100%)than that in group A (65%)(P<0.05).Conclusion The shortest time to elicit waveform of MEPs using the dose of cisatracurium is 0.1 5 mg/kg at induction of general anesthesia,which is better for tracheal intubation.The dose 0.1 5 mg/kg of cisatracurim is recommended as the initial dose on neurosurgery operation with motor e-voked potential monitoring.

Due to the special structure of the nasal cavity, the addition of functional excipients in nasal drugs can improve the transmembrane absorption of the active pharmaceutical ingredient or reduce the clearance of nasal mucocilia, which plays an important role in maintaining the effective concentration of active pharmaceutical ingredient in the target area and promoting the absorption of nasal mucosa. In this paper, the excipients used in drug new approved by the United States Food and Drug Administration(FDA) in the past decade were summarized, and the current research advances and safety evaluation of excipients for nasal drug were reviewed, providing ideas and references for the selection of excipients for nasal drug development.

Objective:To explore the relationship among physical exercise, self-control, and mobile phone dependence in adolescents.Methods:The entire group of random sampling method was used to extract 882 students from five junior high schools in Nanchang city from September 2020 to March 2021.A longitudinal survey was conducted using the sports activity rating scale, self control scale, and adolescent mobile phone dependence scale on all participants for 2 times with an interval for 6 months.The questionnaire results in the first stage were marked as T1.The questionnaire results in the second stage were marked as T2.SPSS 26.0 statistical software was used to conduct reliability analysis, common method bias test and Pearson correlation analysis on each variable in sequence.AMOS 23.0 was used for cross-lag analysis to explore the relationship among physical exercise, self-control and mobile phone dependence.Results:The score of physical exercise of adolescents was (17.71±5.62), the score of self-control was (51.48±9.71), and the score of mobile phone dependencies was (56.67±12.93). Adolescent physical exercise, self-control, and mobile phone dependence were all related to stability across time.There were positive correlation between T1 physical exercise and T2 physical exercise ( r=0.489), T1 self-control and T2 self-control ( r=0.482), as well as T1 mobile phone dependencies and T2 mobile phone dependencies ( r=0.498)(all P<0.01). Cross-lag analysis showed that: adolescent physical exercise behavior could unidirectionally predict self-control( β=0.197, P<0.01)and mobile phone dependence( β=-0.224, P<0.01) after 6 months, and self-control could predict the mobile phone dependence( β=-0.560, P<0.01) of junior high school students after 6 months.The mediating effect results showed that self-control had a mediating effect between physical exercise and mobile phone dependence of junior high school students, there were gender differences.The mediating effect accounted for 22.22%(-0.018/-0.081). Conclusion:Physical exercise can indirectly reduce the mobile phone dependence of junior high school students by affecting self-control.