BACKGROUND: Root canal files fracture is a kind of common oral clinical complications. Therefore, it is of clinical importance to study the cyclic fatigue of different types of stainless steel root canal files.OBJECTIVE: To explore the effect of the bending angle and cross-sectional area of root canal instruments on cyclic fatigue of stainless steel files.METHODS: Thirty 25# stainless steel K files (25 mm in length) were selected, the same to 30# and 35#. And these three kinds of files were respectively randomized into three groups (n=10 per subgroup). In the nine subgroups, the files were placed into self-made root canals at the bending angle of 45°, 60°, 90°, and driven by a 16:1 reducer (350 r/min).Fracture time in each subgroup was recorded and converted into the number of rotations. The microstructure of the fracture end of the files was observed under scanning electron microscope. Fractured files were collected and the crack tip length was measured by an electronic caliper.RESULTS AND CONCLUSION: At the same bending angle, the number of rotations resulting in file fracture was significantly reduced with the increasing of the cross-sectional area of the files (P < 0.05). When the type and cross-sectional area were same, the number of rotations resulting in file fracture was significantly reduced with the increasing of the bending angle of the root canals (P < 0.05), indicating a reduction in the cyclic fatigue performance of the files. Toughness fracture occurred in all the files, and circular or oval roughness nests with different sizes and microcavities formed on the fracture surface. In addition, brittle surfaces could be detective between the roughness nests. The diameter of roughness nests was gradually increased with the increasing of the bending angle of the root canals. For 30# and 35# files, the number of brittle surfaces was gradually increased with the increasing of the bending angle of the root canals. For 25# files, the crack tip length was gradually decreased with the increasing of the bending angle of the root canals, but there was no significant difference (P > 0.05). For 30# and 35# files, the crack tip length was significantly shortened with the increasing of the bending angle of the root canals (P < 0.05). But there were no significant changes in the 35#-60° and 35#-90° groups (P=0.095). At the same bending angle, there were no regular changes in the crack tip length in the different types of files. In conclusion, with the increasing of the cross-sectional area, the cyclic fatigue performance of the files with the same length and taper is reduced and the files become easy to be fractured; with the increasing of the bending angle of the root canals, the files with the same types are apt to be fractured near the root tip, indicating the shorter length of the crack tip indicates the more difficulty in the removal of the broken files.

15mm~2)of dural sac cross-sectional area to values smaller than 75 mm~2 was found during examination in axial loading,or if a suspected disc herniation,narrow lateral recess,narrow intervertebral foramen,or intraspinal synovial cyst changed to being obvious at the axial loading examination,they were regarded as additional information.Results After axial loading CT examination,AVI was found in 16 of 40 patients.A significant decrease of dural sac area was found in 13 patients.Intervertebral disc herniation was more severe in 7 patients,lateral recess or interverbral foramen narrowed in 4 patients,no intraspinal synovial cyst was found.After axial loading MRI examination,AVI was found in 19 of 60 patients.A significant decrease of dural sac area was found in 13 patients.Intervertebral disc herniation became severe in 10 patients,lateral recess or interverbral foramen narrowed in 8 patients,no intraspinal synovial cyst was found.AVI was found in 32 of 79(40.5%)patients with sciatica and 2 of 20(10.0%)patients with low back pain(?~2=7.45 P

Objective To investigate the MRI features of the brain in patients with neuromyelitis optica (NMO), and to evaluate the correlation between the brain abnormalities and related risk factors.Methods Fifty-four patients with definite NMO according to 2006 Wingerchuk diagnosis criteria were enrolled in this study. MRI scanning of the brain was performed in these patients. Distribution and signalfeatures of all the lesions were analyzed. A Logistic regression analysis was used to evaluate the risk factors of brain abnormalities. Results Twenty-four NMO patients (44. 4%) showed unremarkable findings and thirty (55.6%) showed abnormalities on brain MRI. Multiple and non-specific small lesions in the subcortical white matter and grey-white matter junction were the most frequent abnormalities on brain MRI (13/30, 43. 3%). Typical lesion locations included corpus callosum, subependyma of ventricles,hypothalamus and brain stem. The lesions showed punctate, patchy and linear abnormal signals. Postcontrast MRI showed no abnormal enhancement in 16 cases. Logistic regression analysis showed that coexisting anto-immune disease or infection history had correlations with abnormalities of the brain on MRI (OR=3.519,P ＜0.05). Conclusions There was a high incidence of brain abnormalities in NMO.Subependymal white matter, corpus callosum, hypothalamus and brain stem were often involved in NMO.NMO patients with coexisting anto-immune disease and infection history had higher risk of brain abnormalities.

Objective Toinvestigatetheapplicativevalueof3D-DSAandheadMRIorCTfusion technology for guiding the individualized treatment of intracranial arteriovenous malformation (AVM ). Methods Twenty-onepatientswithAVMdiagnosedwithDSAattheDepartmentofNeurosurgery,Nanjing General Hospital of Nanjing Military Command from January 2015 to May 2015 were analyzed retrospectively. All patients performed DSA,MRI,and CT scan respectively before procedure,and they also performed 3 D-DSA and MRI or CT fusion. Of the 21 patients,15 performed MRI and 3D-DSA fusion,6 performed CT and 3D-DSA fusion. According to the image fusion results of the patients,the individualized treatment regimens were further developed,including microsurgical resection,endovascular embolization,and stereotactic radiotherapy (alone or combined treatment). The patients were followed up and observed for 2 to 6 months after procedure.Results Fromthe3D-DSAwithheadMRIorCTfusionimagesofthepatientsbeforetheprocedure not only could observe the vascular architecture of AVM,the relationship between the niduses and the surrounding nerve structures,but also could precisely locate the positions of AVM with small aneurysms or tiny AVMs. According to the results of image fusion,17 patients with AVM were treated with microsurgical resection,2 were treated with interventional embolization and stereotactic radiotherapy,and 2 were treated with stereotactic radiotherapy only. Of the 17 patients with AVM underwent microsurgical resection, none experienced intracranial rebleeding during the follow-up period. The last Glasgow outcome scale (GOS)score was 5 in 13 cases,and 4 in 4 cases. One patient with AVM underwent combined stereotactic radiotherapy had intracranial rebleeding during the follow-up period,and their last GOS score was 4. The other remaining 3 patients did not have new neurological deficits or rebleeding during the follow-up period,and theirGOSscorewas5.Conclusions 3D-DSA,headMRI,andCTfusiontechnologyarenovel, the operative method is simple,and the fusion image is accurate. They can effectively develop the individualized treatment regimens for patients with AVM.

Aim To evaluate the effects of pantoprazole on various experimental acute ulcer inrats and mice. Methods The model of a gastric ulcer of rats or mice was caused bystree- induced ulcer and ligatel pylurus-induced ulcer. Results & Conclusions At adose of 5, 10, 20 mg? kg-1 of Pantoprazole can markedly decrease the ulcer index ofstree-induced ulcer. Pantoprazole(4, 8, 16 mg? kg -1 ) significantly decrease the areaof ligated pylorus-induced gastric ulcer. It was also found that pantoprazole caninhibit the output of basic gastric acid.

Objective: To explore the consumption of sugar sweetened beverages (SSBs) and its association with behavioral problems in Chinese preschool children, and to provide a scientific basis for the prevention of behavioral problems of children. Methods: A total of 7 634 children aged 3-6 years were chosen from kindergartens in 3 cities (Yangzhou, Xuzhou, Zhenjiang) in the lower reaches of Yangtze River using method of cluster sampling during October to November in 2017. Parental or guardian questionnaires were used to obtain information regarding child consumption of SSBs. The Strengths and Difficulties Questionnaire (SDQ) was used to assess children s emotional and behavioral problems. Multivariate Logistic regression model was used to explore the association between different SSBs intake frequency and children s behavioral problems. Results: A total of 5 509(72.2%) consumed SSBs less than once a day, 830(10.9%) reported SSBs consumption once a day, and 1 295(16.9%) had 2 times or more intake of sugar sweetened beverages per day. After adjusting for confounding factors including age, sex, BMI, family financial status, parental education, screen time, sleep duration, and physical activities duration, multiple Logistic regression model revealed that intake of SSBs once a day was associated with an increased risk of hyperactivity disorder ( OR =1.26, 95% CI =1.01-1.57) and SDQ total difficulties ( OR =1.44, 95% CI =1.14-1.82) in boys and with an increased risk of emotional symptoms ( OR=1.34, 95%CI =1.02-1.76), conduct problems ( OR=1.53, 95%CI =1.18-2.00), hyperactivity disorder ( OR=1.79, 95%CI =1.42-2.27) and prosocial behavior ( OR=1.48, 95%CI =1.14-1.91) in girls. Intake of SSBs≥2 times per day was associated with an increased risk of emotional symptoms ( OR=1.28, 95%CI =1.02-1.59) and SDQ difficulties ( OR=1.30, 95%CI =1.07-1.58) in boys and not with behavioral problems in girls. Conclusion Sex differences are observed with respect to the association between SSBs intake and behavioral problems in preschoolers, but no significant dose response relationship was observed. More longitudinal studies are needed to further explore the association between SSBs intake and behavioral problems in preschool children as well as the underlying physiological mechanisms in future.

Objective To detect miR-181d expression levels in colon cancer cell lines,and to study the functions of miR-181d on colon cancer cell proliferation and apoptosis.Methods RT qPCR was employed to study miR-181d cxpression levels in colon cancer cell line HCT116,HT29,LoVo,SW480 and SW620 cells,as well as in colon normal epithelial cell line HIEC.miR-181d mimic and control were transfected into LoVo cells while miR-181d inhibitor and control were transfected into SW620 cells.qRT-PCR was performed to validate the transfection efficiency.MTT assay was performed to measure cell proliferation while flow cytometry was performed to detect cell cycle and apoptosis rate.Results miR-181d was universally downregulated in all colon cancer cell lines compared to the colon normal epithelial cell line HIEC (F=29.34,P＜0.01).Overexpression of miR-181d in LoVo cells significantly decreased in vitro cell proliferation rate (F=5.403,P＜0.01).Flow cytometry indicated that cells at S phase were greatly decreased (t=4.71,P＜0.05) and apoptotic cells were gready increased compared to the control cells (t=3.47,P＜0.05).On the contrary,inhibition of miR-181d in SW620 cells significantly promoted cell proliferation (F=20.82,P＜0.01).Cell cycle was accelerated with significant increase in S phase compared to the control cells (t=2.92,P＜0.05),whereas apoptosis rano was significantly decreased (t=4.14,P＜0.05).Conclusion miR-181d was universally downregulated in colon cancer cell lines compared to the normal epithelial cell line.miR-181d inhibits cell proliferation and induces apoptosis,thus functions as an tumor suppressive miRNA.

Communion is an important way to study.Interaction is the most notable character of network.This paper introduces some experience on how to bring net interaction into play in the network-based medical teaching.

Objective To explore the treatment of acquired benign tracheoesophageal fistula.Methods Clinical data of 13 cases of acquired benign tracheoesophageal fistula were retrospectively studied and the related literature was reviewed.The physical conditions,locations of fistula and risk factors of the patients were assessed before surgery.A specific surgical protocol was determined for each individual patient using either radical surgery or palliative surgery to repair the fistula.Ten patients underwent radical surgery,including suture closure of the esophageal or tracheal defects only in 7 patients and segmental tracheal reseetion in 3 patients.The remaining 3 patients underwent palliative operation.Results No major complication was observed except pulmonary infectin in 2 patients.No patient died during the perioperative period.All but one patient who treated with mediastinal and neck radiation therapy 4 years ago were able to resume oral food three months after operation.All patients were followed up for 8 months to 73 months[mean (39.6 ± 19.7) months]and no fistulas were occurred in the patients who received a radical surgery.The tracheoesophageal fistula orifices became smaller or closed fairly well in the patients who underwent a palliative surgery.Conclusion Surgery is the treatment of choice for acquired benign tracheoesophageal fistula.Airway and esophagal stent placement is not recommended.Adequate drainage of gastric juice is a crucial step in the management of the condition.

Objective To evaluate maximum intensity projection(MIP) images and apparent diffusion coefficient(ADC) values of MR diffusion weighted imaging with background body signal suppression (DWIBS) on pulmonary diseases.Methods Sixty-one patients with pulmonary diseases underwent DWIBS.The findings in three dimensional(3D) MIP image were observed and the ADC values of diseased region were measured.The diagnostic value of DWIBS on pulmonary diseases was evaluated.Results Lung cancer and inflammatory disease were all demonstrated as dense intensity area on DWIBS.The mean ADC value of central lung cancer was (1.05±0.23)×10-3 mm2/s.The mean ADC value of peripheral lung cancer was(1.10±0.17)×10-3 mm2/s.The mean ADC value of the inflammatory disease was(1.69±0.29)×10-3 mm2/s.The mean ADC value had significant difierence between peripheral lung cancer and the inflammatory disease (P＜0.05). The MR sensitivity,specificity and accuracy in diagnosing the pulmonary diseases with DWIBS(86.84%,82.60%,85.24%,respectively) was higher than conventional MRI(78.94%,78.26%,and 78.68%,respectively).Conclusion DWIBS can demonstrate clearly the lesion's shape with 3D display.The quantitative measurement of ADC values iS feasible.DWIBS may be a potential diagnostic method for differentiation on pulmonary diseases.