BACKGROUND:The elastic modulus of traditional solid titanium alloy implants is higher than that of human bone,and the resulting"stress shielding"phenomenon may affect the osseointegration of implants.Simultaneously,the wettability of 3D printed titanium alloy surface needs to be improved.OBJECTIVE:To prepare hydrophilic Gyroid implants with excellent biomechanical properties.METHODS:The 3D models of Gyroid implant,solid implant,mandibular bone and crown were established,and the mechanical properties of different implants were analyzed by finite element analysis.The Gyroid structure implant model was imported into the 3D printer to make the Gyroid structure implant materialized,and then the hydrophilic Gyroid structure implant with excellent mechanical properties and surface activity was prepared by sandblasting acid etching and ultraviolet functionalization.The morphology and hydrophilicity of 3D printed Ti6Al4V specimens before and after surface modification were analyzed by scanning electron microscopy and contact angle test.RESULTS AND CONCLUSION:(1)The finite element analysis results showed that under the vertical average bite force,the Gyroid structure could uniformly disperse the load acting on the implant into the entire structure.The load on the solid structure implant could only be dispersed on its outer surface and concentrated in the neck.The maximum equivalent stress of the Gyroid structure implant was 200.67 MPa,which did not exceed 50%of the yield strength of Ti6Al4V material.The maximum equivalent stress of the Gyroid structure implant on the surrounding bone tissue was 24.27 MPa,which was slightly higher than the maximum equivalent stress of the solid structure implant 17.32 MPa,and in the range of 20-60 MPa.The stimulation effect of the Gyroid structure implant on new bone formation was better than that of the solid structure implant.(2)The 3D printing technology could materialize the Gyroid structure implant model.Scanning electron microscopy showed that there were many unmelted spherical metal particles on the surface of the 3D printed Ti6Al4V specimens.After sandblasting and acid etching,a micron-scale mesh pore structure was formed on the surface,and no protruding metal particles were seen.The surface morphology of the superimposed UV functional treatment group was basically consistent with that after sandblasting and acid etching.The contact angle test results showed that the surface hydrophilicity of the specimens treated with ultraviolet functionalization plus sandblasting and acid etching was better than that of the sandblasting and acid etching and non-surface treatment groups.(3)The sandblasting and acid etching technology can remove the weakly connected metal particles on the 3D printed specimen and improve the similarity between the solid model and the design model.On this basis,the ultraviolet functionalization treatment can significantly improve the hydrophilicity of the 3D printed Gyroid structure implant surface without affecting its structure.

BACKGROUND:The elastic modulus of traditional solid titanium alloy implants is higher than that of human bone,and the resulting"stress shielding"phenomenon may affect the osseointegration of implants.Simultaneously,the wettability of 3D printed titanium alloy surface needs to be improved.OBJECTIVE:To prepare hydrophilic Gyroid implants with excellent biomechanical properties.METHODS:The 3D models of Gyroid implant,solid implant,mandibular bone and crown were established,and the mechanical properties of different implants were analyzed by finite element analysis.The Gyroid structure implant model was imported into the 3D printer to make the Gyroid structure implant materialized,and then the hydrophilic Gyroid structure implant with excellent mechanical properties and surface activity was prepared by sandblasting acid etching and ultraviolet functionalization.The morphology and hydrophilicity of 3D printed Ti6Al4V specimens before and after surface modification were analyzed by scanning electron microscopy and contact angle test.RESULTS AND CONCLUSION:(1)The finite element analysis results showed that under the vertical average bite force,the Gyroid structure could uniformly disperse the load acting on the implant into the entire structure.The load on the solid structure implant could only be dispersed on its outer surface and concentrated in the neck.The maximum equivalent stress of the Gyroid structure implant was 200.67 MPa,which did not exceed 50%of the yield strength of Ti6Al4V material.The maximum equivalent stress of the Gyroid structure implant on the surrounding bone tissue was 24.27 MPa,which was slightly higher than the maximum equivalent stress of the solid structure implant 17.32 MPa,and in the range of 20-60 MPa.The stimulation effect of the Gyroid structure implant on new bone formation was better than that of the solid structure implant.(2)The 3D printing technology could materialize the Gyroid structure implant model.Scanning electron microscopy showed that there were many unmelted spherical metal particles on the surface of the 3D printed Ti6Al4V specimens.After sandblasting and acid etching,a micron-scale mesh pore structure was formed on the surface,and no protruding metal particles were seen.The surface morphology of the superimposed UV functional treatment group was basically consistent with that after sandblasting and acid etching.The contact angle test results showed that the surface hydrophilicity of the specimens treated with ultraviolet functionalization plus sandblasting and acid etching was better than that of the sandblasting and acid etching and non-surface treatment groups.(3)The sandblasting and acid etching technology can remove the weakly connected metal particles on the 3D printed specimen and improve the similarity between the solid model and the design model.On this basis,the ultraviolet functionalization treatment can significantly improve the hydrophilicity of the 3D printed Gyroid structure implant surface without affecting its structure.

Pulmonary hypertension (PH) is an extremely malignant pulmonary vascular disease of unknown etiology. ADAR1 is an RNA editing enzyme that converts adenosine in RNA to inosine, thereby affecting RNA expression. However, the role of ADAR1 in PH development remains unclear. In the present study, we investigated the biological role and molecular mechanism of ADAR1 in PH pulmonary vascular remodeling. Overexpression of ADAR1 aggravated PH progression and promoted the proliferation of pulmonary artery smooth muscle cells (PASMCs). Conversely, inhibition of ADAR1 produced opposite effects. High-throughput whole transcriptome sequencing showed that ADAR1 was an important regulator of circRNAs in PH. CircCDK17 level was significantly lowered in the serum of PH patients. The effects of ADAR1 on cell cycle progression and proliferation were mediated by circCDK17. ADAR1 affects the stability of circCDK17 by mediating A-to-I modification at the A5 and A293 sites of circCDK17 to prevent it from m1A modification. We demonstrate for the first time that ADAR1 contributes to the PH development, at least partially, through m1A modification of circCDK17 and the subsequent PASMCs proliferation. Our study provides a novel therapeutic strategy for treatment of PH and the evidence for circCDK17 as a potential novel marker for the diagnosis of this disease.

Objective:To study the prevalence and correlations of HIV infection among cross-border couples in the Dehong prefecture.Methods:A cross-sectional mass screening study with questionnaire interview and HIV testing was conducted among 17 594 registered cross-border couples from May 2017 through June 2018.Results:Among 32 400 participants, the overall prevalence of HIV infection was 2.27% (736/32 400), 2.44% (375/15 372) for Chinese citizens, and 2.12% (361/17 028) for foreign spouses. Among all the 13 853 couples with both spouses receiving HIV testing, 13 415(96.84%) were seroconcordant-negative couples, 142(1.03%) were serocondordant-positive couples, and 296(2.13%) were serodiscordant couples, including 167(1.20%) couples with positive husband and negative wife and 129(0.93%) couples with positive wife and negative husband. Multiple logistic regression analyses indicated that HIV infection was associated with drug use and risky sexual behaviors for male spouses. In contrast, HIV infection was associated with risky sexual behaviors for female spouses.Conclusion:The prevalence of HIV among cross-border couples in Dehong prefecture is high, underscoring the urgent need to scale up HIV testing, prevention, and behavioral intervention.

From January 15 to March 3, 2020, seven editions of the guidelines for the diagnosis and treatment of COVID-19 have been issued successively by the National Health Commission of the People's Republic of China, and the guidelines' name was changed from Guidelines for Diagnosis and Treatment of Novel Coronavirus Pneumonia to Diagnosis and Treatment for COVID-19. It optimized and perfected the etiology, clinical manifestations and types, diagnostic procedures and specific treatment measures of the disease, so that the clinical management of the cases was more scientific. In the revision process of guidelines for diagnosis and treatment, forensic medicine experts have also made some positive suggestions on clinical diagnosis and treatment. Especially regarding the pathological changes of COVID-19, they have repeatedly called for rapid autopsy at different levels. With the support, understanding and cooperation of all parties, pathological examination of more than ten cases of the remains were carried out, which made an important contribution to the understanding of the clinical characteristics and pathological characteristics of the disease and the improvement of treatment plans.
COVID-19 ; China ; Clinical Protocols ; Forensic Medicine ; Humans ; SARS-CoV-2

Objective To investigate the toxic reaction,toxic organs or target tissues of protamine recombinant human insulin (Insulin NPH),and provide basis for clinical trials by single dose toxicity test in mice,repeated toxicity and immunogenicity of Beagle's dogs,and systemic active allergy in guinea pig.Methods ① Using maximum dose method,mice in single dose toxicity test were sc injected with normal saline (NS),vehicle,and Insulin NPH (2092-2488 IU/kg),the toxic reactions after injection were monitored.② In repeated toxicity study,Beagle's dogs were sc administrated with vehicle,the original (Humulin NPH,1.5 IU/kg)and different doses of Insulin NPH (0.5,1.0 and 1.5 IU/kg) for 30 d continuously,followed by a 14-d recovery.During the administration and recovery period,general observation,local irritation,body weight,anus temperature,blood glucose,and electrocardiogram (ECG) were checked,moreover,hematology,serum biochemistry and urine were detected.Also,organic weights and histopathological examination were conducted.Binding antibodies in dog serum were measured by indirect ELISA method in immunogenicity test.③ In systemic active allergy study,cavies were sc injected with low-and high-dose (4 and 12 IU/kg) Insulin NPH,normal saline and vehicle.Besides,ova as positive control was also included.After five times of sensitization test with above doses,the excitation reactions of iv injection with tripled sensitizing doses were observed.Results No obvious toxicity was observed in mice after injected with 165 times of usual clinical dose of Insulin NPH.Repeated toxicity study of Beagle's dogs revealed that 1.0 IU/kg was the no-toxic-effect dose (NOAEL) for Insulin NPH,which was equivalent to 2 times of clinical dose.No bindingantibodies were found in immunogenicity test.There was no obvious allergic symptom in the active systemic allergy study of guinea pig.Conclusion Under the experimental conditions,no serious toxicity of Insulin NPH is found.