Objective·To fabricate a 3D-printed dental crown and bridge resin slurry using digital light processing(DLP)technology,investigate the influence of different printing parameters on its mechanical properties,determine the optimal printing parameters,and optimize the composition ratio of DLP-printed crown and bridge resin.Methods·Based on the viscosity characteristics of the mixture,the optimal ratio of urethane dimethacrylate(UDMA)to poly(propylene glycol)dimethacrylate(PPGDMA)was explored.After silanizing silicon dioxide(SiO2),it was mixed with UDMA,PPGDMA,and 2,4,6-trimethylbenzoyl bis(p-tolyl)phosphine oxide(TMO)to prepare DLP-printed dental crown and bridge resin slurries with different solid contents,and their rheological properties were tested.The Beer-Lambert equation was used to calculate the light penetration depth and critical exposure energy of the printing slurry.Based on these values,different exposure intensities,exposure times,post-curing times,and layer thicknesses were set respectively to carry out a series of printing experiments.By comparing and analyzing the flexural strength of the products under different printing parameters,the optimal printing parameter combination was screened out.Results·Viscosity tests showed that the optimal UDMA-to-PPGDMA ratio was 6∶4.The rheological behavior of printing slurries with different solid contents was tested,and the results showed that the DLP-printed dental crown and bridge resin with a solid content of 22%exhibited the best printing performance.According to the Beer-Lambert analysis,the light penetration depth Dp of the printing slurry was 119.79 μm,and the critical exposure energy Ec was 25.54 mJ/cm2.When the exposure intensity was 20 mW/cm2,the flexural strength reached a maximum of(132.39±8.92)MPa,and the difference was statistically significant(P<0.05).The flexural results of different exposure times showed that the flexural strength could reach(131.73±9.43)MPa when the single-layer exposure time was 3.0 s,and there was no significant difference when the exposure time was further increased.The flexural results of different post-curing times showed that when the post-curing time reached 30 min,there was no significant relationship between the flexural strength value and the increase in post-curing time.Regarding the influence of different layer thicknesses on the flexural performance,the test results showed that when the layer thickness was 50 μm,the result was the best,and the difference was statistically significant(P<0.001).Conclusion·Based on viscosity and rheological tests,a DLP-printable crown and bridge resin slurry was successfully developed.The optimal printing parameters were determined through statistical analysis of flexural strength:exposure intensity of 20 mW/cm2,exposure time of 3.0 s,post-curing time of 30 min,and a layer thickness of 50 μm.

Objective·To fabricate a 3D-printed dental crown and bridge resin slurry using digital light processing(DLP)technology,investigate the influence of different printing parameters on its mechanical properties,determine the optimal printing parameters,and optimize the composition ratio of DLP-printed crown and bridge resin.Methods·Based on the viscosity characteristics of the mixture,the optimal ratio of urethane dimethacrylate(UDMA)to poly(propylene glycol)dimethacrylate(PPGDMA)was explored.After silanizing silicon dioxide(SiO2),it was mixed with UDMA,PPGDMA,and 2,4,6-trimethylbenzoyl bis(p-tolyl)phosphine oxide(TMO)to prepare DLP-printed dental crown and bridge resin slurries with different solid contents,and their rheological properties were tested.The Beer-Lambert equation was used to calculate the light penetration depth and critical exposure energy of the printing slurry.Based on these values,different exposure intensities,exposure times,post-curing times,and layer thicknesses were set respectively to carry out a series of printing experiments.By comparing and analyzing the flexural strength of the products under different printing parameters,the optimal printing parameter combination was screened out.Results·Viscosity tests showed that the optimal UDMA-to-PPGDMA ratio was 6∶4.The rheological behavior of printing slurries with different solid contents was tested,and the results showed that the DLP-printed dental crown and bridge resin with a solid content of 22%exhibited the best printing performance.According to the Beer-Lambert analysis,the light penetration depth Dp of the printing slurry was 119.79 μm,and the critical exposure energy Ec was 25.54 mJ/cm2.When the exposure intensity was 20 mW/cm2,the flexural strength reached a maximum of(132.39±8.92)MPa,and the difference was statistically significant(P<0.05).The flexural results of different exposure times showed that the flexural strength could reach(131.73±9.43)MPa when the single-layer exposure time was 3.0 s,and there was no significant difference when the exposure time was further increased.The flexural results of different post-curing times showed that when the post-curing time reached 30 min,there was no significant relationship between the flexural strength value and the increase in post-curing time.Regarding the influence of different layer thicknesses on the flexural performance,the test results showed that when the layer thickness was 50 μm,the result was the best,and the difference was statistically significant(P<0.001).Conclusion·Based on viscosity and rheological tests,a DLP-printable crown and bridge resin slurry was successfully developed.The optimal printing parameters were determined through statistical analysis of flexural strength:exposure intensity of 20 mW/cm2,exposure time of 3.0 s,post-curing time of 30 min,and a layer thickness of 50 μm.

Objective:To explore the clinical efficacy of biopsy forceps polypectomy with submucosal injection for diminutive colorectal polyps.Methods:The patients with diminutive colorectal polyps (long diameter≤5 mm in size) who received polypectomy in Quanzhou First Hospital Affiliated to Fujian Medical University from May 2021 to May 2022 were prospectively recruited and divided into the observation group (biopsy forceps polypectomy with submucosal injection) and the control group (traditional biopsy forceps polypectomy). The location, morphology, long diameter, the complete polypectomy rate under direct vision, the time of resection and endoscopy withdrawal, pathological results, specimen collection rate, the incidence of complications and endoscopic treatment cost were analyzed. The clinical efficacy of the two methods were compared.Results:A total of 292 patients were included in the study, with 146 in the observation group and 146 in the control group. There were 258 polyps in the observation group and 252 polyps in the control group. The complete polypectomy rate was higher in the observation group than that in the control group [100.0% (258/258) VS 90.1% (227/252), χ2=26.915, P=0.001] with clear vision. The incidence of complications in the observation group was lower than that in the control group (1/146 VS 13/146, χ2=10.804, P=0.001) , along with the lower treatment cost (173.7±15.9 yuan VS 184.0±53.8 yuan, Z=-2.777, P=0.005). The resection time in the observation group was longer than that in the control group, but the difference was not statistically significant [10 (9,11) min VS 9 (9,11) min, Z=-0.528, P=0.597]. There was no significant difference in the polyp position, long diameter, morphology, pathological classification, or the specimen collection rate between the two groups ( P>0.05). Conclusion:Biopsy forceps polypectomy with submucosal injection is safe for diminutive colorectal polyps, and it demonstrates a higher complete polypectomy rate, lower complication rates, and reduced treatment costs compared with traditional biopsy forceps polypectomy. It is a new perspective for managing diminutive colorectal polyps.

Objective:To explore the clinical efficacy of biopsy forceps polypectomy with submucosal injection for diminutive colorectal polyps.Methods:The patients with diminutive colorectal polyps (long diameter≤5 mm in size) who received polypectomy in Quanzhou First Hospital Affiliated to Fujian Medical University from May 2021 to May 2022 were prospectively recruited and divided into the observation group (biopsy forceps polypectomy with submucosal injection) and the control group (traditional biopsy forceps polypectomy). The location, morphology, long diameter, the complete polypectomy rate under direct vision, the time of resection and endoscopy withdrawal, pathological results, specimen collection rate, the incidence of complications and endoscopic treatment cost were analyzed. The clinical efficacy of the two methods were compared.Results:A total of 292 patients were included in the study, with 146 in the observation group and 146 in the control group. There were 258 polyps in the observation group and 252 polyps in the control group. The complete polypectomy rate was higher in the observation group than that in the control group [100.0% (258/258) VS 90.1% (227/252), χ2=26.915, P=0.001] with clear vision. The incidence of complications in the observation group was lower than that in the control group (1/146 VS 13/146, χ2=10.804, P=0.001) , along with the lower treatment cost (173.7±15.9 yuan VS 184.0±53.8 yuan, Z=-2.777, P=0.005). The resection time in the observation group was longer than that in the control group, but the difference was not statistically significant [10 (9,11) min VS 9 (9,11) min, Z=-0.528, P=0.597]. There was no significant difference in the polyp position, long diameter, morphology, pathological classification, or the specimen collection rate between the two groups ( P>0.05). Conclusion:Biopsy forceps polypectomy with submucosal injection is safe for diminutive colorectal polyps, and it demonstrates a higher complete polypectomy rate, lower complication rates, and reduced treatment costs compared with traditional biopsy forceps polypectomy. It is a new perspective for managing diminutive colorectal polyps.

Abstract: Objective To compare the diagnostic efficacy of the upgraded version of the GeneXpert automated fluorescent quantitative PCR system (GeneXpert MTB/RIF Ultra, GeneXpert Ultra) and the original version of the GeneXpert system (GeneXpert MTB/RIF, Xpert), real-time fluorescent quantitative nucleic acid detection (FQ-PCR), real-time fluorescent thermostatic amplification of Mycobacterium tuberculosis RNA (SAT-RNA), real-time fluorescent thermostatic amplification detection of DNA (thermostatic amplification method) and traditional BACTEC MGIT 960 liquid culture (culture method) for special specimens of tuberculosis, in order to analyze its application value in clinical detection. Methods Using prospective research methods, a total of 170 special specimens (including 47 pleural and ascites effusion samples, and 34 24-hour urinary sediment specimens, 49 tissue specimens and 40 fester specimens) were collected i'an Chest Hospital from January to September 2021. GeneXpert Ultra, Xpert, FQ-PCR, SAT-RNA, isothermal amplification, and traditional culture were used for detection. Clinical diagnosis was used as the standard, and sensitivity, specificity, positive predictive value, negative predictive value, coincidence rate, and Kappa value were compared among the methods. Results The sensitivities of GeneXpert Ultra, Xpert, FQ-PCR, SAT-RNA, isothermal amplification, and traditional culture were 65.18% (73/112), 49.11% (55/112), 37.50% (42/112), 19.64% (22/112), 8.04% (9/112), and 22.32% (25/112), respectively. The sensitivity of GeneXpert Ultra was higher than that of the other five methods, and the differences were statistically significant (χ2=66.25, 42.10, 28.89, 13.09, 4.92, 15.18, all P<0.05). GeneXpert Ultra result analysis showed that: 5.48%(4/73) cases had trace, that is, trace Mycobacterium tuberculosis load, 79.45% (58/73) cases were extremely low, 10.96% (8/73) cases were low, 2.74% (2/73) were medium, , and 1.36% (1/73) were high load. In 4 trace samples, the Xpert detection was negative for all. Of the 73 GeneXpert Ultra positive reports, 63 were rifampicin-sensitive, 6 were rifampicin-resistant, and 4 were rifampicin-resistant but of unclear resistance. Of the 55 Xpert positive reports, 45 were rifampicin-sensitive, 2 were rifampicin-resistant, and 8 were rifampicinresistant but of unclear resistance.. Conclusions The new generation of GeneXpert MTB/RIF Ultra has high sensitivity, specificity and drug resistance detection rate, and its advantage is even more apparent in the pathogenic diagnosis of special specimens of tuberculosis. It can be used as one of the preferred methods in samples with low bacterial load.

Objective:To explore whether the 15-minute retention rate (R15) of indocyanine green (ICG) in the indocyanine green excretion test and the effective hepatic blood flow (EHBF) can predict the occurrence of mild hepatic encephalopathy (MHE).Methods:Using the convenience sampling method, we collected clinic data from 153 patients diagnosed with liver cirrhosis or liver failure from June 2019 to December 2019 in the Third Affiliated Hospital of Sun Yet-sen University in Guangzhou. We screened the MHE patients with the number connect test-A and the digital symbol test, and analyzed the clinical data. By taking different values for R15 and EHBF as cut-off points, the significance of the two factors in predicting MHE is explored respectively.Results:The incidence of MHE was 38.56% (59/153). Single factor analysis showed that the difference of Child-Pugh grade between the MHE group and the non-MHE group was statistically significant ( χ2 value was 7.606, P<0.05), while the differences between cirrhosis and liver failure diagnosis, fasting blood glucose, and serum creatinine were not statistically significant ( P>0.05). When most points between 0.11 and 0.61 were selected as normal and abnormal cut-off points of R15, R15 had statistical significance ( P<0.05) and when R15 selected 0.18, it was most significant (Fisher exact test P=0.00024). When most points between 0.08 and 0.76 were selected as normal abnormal cut-off points of EHBF, EHBF had statistical significance ( P<0.05) and when EHBF selected 0.25, it was most significant (Fisher exact test P=0.00022). Through Logistic stepwise regression analysis, the risk factors for MHE were R15 and EHBF. The ROC curve was used to illustrate the predictive effects of two factors on MHE. Conclusions:The incidence of MHE in patients with cirrhosis or liver failure is high. When R15≥0.18 or EHBF≤0.25 L/min, R15 and EHBF in indocyanine green excretion test can better predict the occurrence of MHE than Child-Pugh classification, and can be help to evaluate and manage patients in time.

Objective:To investigate the feasibility, efficacy, and safety of CT- and bronchoscopy-guided 125I seed implantation in the treatment of central lung cancer complicated with atelectasis. Methods:Retrospective analysis was conducted on twenty-nine patients who were treated from May 2016 to Oct 2019 in the Second Hospital of Tianjin Medical University for central non-small-cell lung carcinoma complicated with pulmonary atelectasis that was inoperable due to medical reasons. 125I seeds were implanted into the trachea under the guidance of bronchoscopy first.The 125I seeds were then implanted into the hilum of the lungs by percutaneous puncture under the guidance of the CT and template.The seed activity was 18.5-29.6 MBq, and the prescription dose was 120 Gy.TPS planning and quality verification were performed before and after the operations.The rate of atelectasis recanalization, the satisfactory rate of dose verification, the improvement of dyspnea index, the survival time, and the adverse events during and after operation were observed. Results:All 29 patients with lung cancer complicated with atelectasis successfully completed the seed implantation, and the satisfactory rate of quality verification was 93.1%.The rate of atelectasis recanalization at 2, 6, 12, 18, and 24 months was 93.1%, 89.7%, 78.6%, 76.2%, and 60%, respectively.Their dyspnea and anoxia symptoms were significantly relieved in 5-28 months after treatment.The results showed that the patients′ dyspnea index was 2.8-0.8 before treatment and 1.4-0.9 after treatment.The median follow-up period was 20 months and median survival was 21 months.Adverse events associated with the radiation therapy included pneumothorax, hemoptysis, cough, fever, and particle displacement.No level-3 or more serious adverse events occurred.Conclusions:The CT- and bronchoscopy-guided 125I seed implantation is a safe and effective therapy option for the treatment of central non-small-cell lung carcinoma associated with atelectasis.It contributes to a high rate of local recanalization, and can rapidly improve clinical conditions and quality of life of the patients with few adverse reactions.

Objective·To compare the stress distribution at abutments, edentulous ridge, and peri-implant tissue under the vertical load between the RPI-type removable partial denture supported by implants with different diameter and the conventional RPI-type removable partial denture using a three-dimensional photoelastic method. Methods·The mandibular Kennedy I type denture defect models were fabricated according to the standard mandibular model. Four Straumann system soft tissue level implants with different diameters (two 4.1 mm implants and two 3.3 mm implants) were implanted into the bilateral first molar areas. Planting nails and epoxy resin teeth were inversely put into the mandibular silicone rubber molds to fabricate the epoxy resin photoelastic models and the regular neck (RN) healing abutments were screwed into the implants. A simulated alveolar mucosa with thickness of 2mm and a conventional RPI-type removable partial denture were placed on the epoxy resin models with or without implants. Then a force of 1 kg was vertically applied by a bite force loading device which fixed the model and denture in the centric occlusion. After the stress was frozen, model slices at different areas were cut and the stress fringes were observed. The stress was calculated according to the fringe value of per unit thickness. Results·For the conventional RPI-type removable partial denture, the maximum stress of distal abutment was mainly concentrated on the apical regions and the maximum stress of edentulous ridge was concentrated on the first molar area, particular on the lingual side of alveolar bone. For the implant-supported RPI-type removable partial denture, the maximum stress of distal abutment was lower than that of the conventional RPI-type removable partial denture, and the maximum stress of edentulous ridge (without the implants) was similar to that of abutment and supporting tissues and was lower than that of the conventional RPI-type removable partial denture. The stress around the implant was the largest and the peri-apical stress of implant was greater than the neck stress of implant. Meanwhile, the maximum stress around the implant was increased with the decrease of implant diameter. Conclusion·Compared to the conventional RPI-type removable partial denture, removable partial dentures supported by implants are more stable with a more balanced stress distribution in supporting tissues, thus benefit the health of abutments and supporting tissues.

To discover medical teaching method which is more funny and effective in early clinical contact education, Eye optical hospital affiliated to Wenzhou Medical University set up oph-thalmic microsurgery experience teaching course for junior medical students and set a variety of eye surgery simulation experience content, such as conjunctival suture surgery, corneal suture surgery, cataract surgery, eye surgery simulation and so on, which can effectively arouse students' professional interest in learning and promote students' thinking and exploration to their profession.

BACKGROUND:Atlantoaxial anatomical structures were special. Compared with thoracolumbar vertebrae, there is no fixed anatomical marker for screw implantation. Moreover, pedicle structural variation is great. The current consensus view is to suggest an individualized program of pedicle screws. The development of orthopedic digital software technology provides a novel manner for preoperative design.
OBJECTIVE:To original y design 3D matrix model, to observe atlas pedicle channel, pedicle screw safety zone, to measure optimal program for screw fixation, and to simplify preoperative design of entering pedicle screw.
METHODS:Continuous atlas CT data of 12 healthy adults in picture archiving and communication system of People’s Hospital, Three Gorges University were imported into Mimics 10.01 software. There were seven males and five females, at the age of 30-65 years old, averagely 45 years. After three-dimensional reconstruction, the three-dimensional reconstruction models were imported into 3Dmax 2009 as .dwg format. The reference three-dimensional planes and the sites of nail insertion were determined by the atlas modeling. The modeling consisted of 17×17×2 elements and the transverse section angles ranged from 0° to 40° and the sagittal section angles ranged from 0° to 40° with a space of 2.5°. 578 elements were used to simulate pedicle screw array model. Perspective observation showed that the diameter was 3.5 mm, and length was 22 mm in pedicle channel. Thus, safety area, best screw channel and screw angle were analyzed.
RESULTS AND CONCLUSION:The total number of elements in the matrix study was 17×17×2×12 in 12 subjects. 175 screws in total of 6 936 units could safely meet the operative standard. No significant difference in the number of pedicle screw between left and right sides (P>0.05). Results indicated that the digital three-dimensional modeling technology is an effective, simple, accurate way in the preoperative design and measurement for atlas pedicle surgery.