Objective:To investigate the ability of fluoride toothpaste and fluoride varnish on enamel remineralization and acid resist-ance.Methods:Enamel specimens were prepared from bovine incisors,and were randomly divided into 4 groups(n=3)after acid-etching by 37%phosphoric acid.Specimens in group A(control)was processed daily with normal saline;those in group B and C were treated once with Duraphat varnish and Fluor Protector varnish respectively;in group D was daily processed with fluoride toothpaste. All specimens were incubated in artificial saliva for 2 weeks.Then all specimens received acid-etching again.Micro-hardness test, SEM observation and image analysis were performed before and after each step.Results:After 2 weeks of processing,no remineraliza-tion was found in group A.Varnish layers were observed on the surface of specimens in group B and C.In group D remineralization was detected on the enamel surface.After re-etching,micro-hardness decreased in group A and D.Fluoride varnish layers in group B and C showed strong resistance to acid-etching.After re-etching,area of micro-holes in group A and D increased(P<0.05 ),but that in group D was smaller than in the control(P<0.05).No micro-hole was observed in group B and group C.Conclusion:Protec-tive layer formed on the enamel surface by fluoride varnish is resistant to acid-etching and promotes enamel remineralization.Fluoride toothpaste application can promote enamel remineralization,but with less resistance to acid.

Objective; To investigate the immunolocalization and significance of Notch-2 expression in the process of dental pulp repair after injury. Methods: An experimental animal model of injury-induced pulpitis was established to observe the time-sequenced alteration of the expression of Notch-2. Results: Three days post-operation, weak positive staining of Notch-2 was observed in pulp mesenchyme cells and pulp fibroblasts but not in vascular endothelial cells or odontoblasts. Five days post-operation, strong Notch-2 reactivity was found in subodontoblasts as well as newly bom capillary endothelial cells. Seven days after cavity preparation, Notch-2 staining became weaker in pulp mesenchyme cells and capillary endothelial cells, but stronger positive staining was found in odontoblasts. Two weeks post-operation, weak Notch-2 staining was seen in pulp mesenchyme cells and subodontoblastic layer cells and was absent from odontoblasts. Notch-2 immunoreactivity was completely absent in intact rat dental pulp. Conclusion: Notch-2 is strikingly up-regulated in dental pulp mesenchyme cells in the early days after dental injury and then shows progressively up-regulation in odontoblasts. Properly regulated activation of Notch signaling pathway is important for controlling cell fate and maintaining the correct balance among cell proliferation, differentiation and apoptosis during dental pulp repair process.

Object To select quality species of Erigeron breviscapus (Vant.) Hand.-Mazz. and study its growing practice and cultural habit. Methods The yield and content of breviscapinun of six species of E. breviscapus, the process of germinating and sprouding of its seeds, growing in the field, and content of breviscapinun of dry E. breviscapus in different growth duration were observed. Results The yield and content of breviscapiniun of QS-3, QS-6, and QS-1 of E. breviscapus species were higher than thatin others, and their yield in plastic green house is higher than that on open plots; with other crop, the percent of germinating and sprouding were lower, this process needs longer time; biomass of E. breviscapus under culturing is larger than that under wild; the content of breviscapinun of its dry grass in different growth duration is different, it is the highest of all flowering time. At last, methods of culture technology are put forward with above characteristics. Conclusion It will be optimistic to plant E. breviscapus artificilly.

Objective To investigate the network information behavior characteristics of medical staff for improving the information service of hospital libraries.Methods The network information behaviors of medical staff were analyzed in aspects of the flow rate on Website, the number of off-station linkages, the times of page visiting, the time preference of users information behaviors, browsers, and access devices according to the Web log processed by Piwik analysis software.Results The information behaviors of medical staff were frequent.Their major objective was to use the electronic resources.The information behaviors of medical staff were focused on their working time.Conclusion Hospital libraries should strengthen the construction of their Website contents, optimize their Website design, update their information and improve their information service according to the time preference of their users information behaviors.

Objective The aim of this study is to evaluate the feasibility of using orthogonal kilo voltage fluoroscopic imaging(OKVFI)for setup correction in image guided radiotherapy of the liver.Methods After positioned the patients with liver cancer implanted with silver rings on the accelerator equipped with kilo voltage X-ray volume imaging(XVI),averaged OKVFI and cone beam CT(CBCT) volumetric images were acquired.A total of 90 datasets of averaged OKVFI and 90 datasets of volumetric images for 10 patients were obtained.The couch shifts obtained by the matching between OKVFI and digitally reconstructed radiograph were compared tu those achieved by the registration between CBCT and 4D reference average CT.On the comparison of the two different matching metheds.the Pearson coefficient was used to analyzed the correlation and Bland-Altman analysis to discern the consistence.Results The Pearson coefficient of correlation for the patient position shifts were R2=0.821.0.771 and 0.909 in the left-right (LR),anterior-posterior(AP)and superior-inferior(SI)directions respectively.95% CI were-2.30 -1.53(LR),-2.06-3.01(AP)and-2.69-1.53(SI)respectively.Within a±3 mm tolerance were 97.78%.95.56%and 96.67%respectively.Conclusions OKVFI has hish correlation and consistence with CBCT image on the setup correction.It is feasible to implement position correction with OKVFI in clinic practice.

Objective:To invest the risk factors associated with delayed hemorrhage after pancreaticoduodenectomy occurred.Methods:A retrospective analysis was performed from January 2012 to June 2015 Shengjing hospital 511 cases of patients who accepted pancreaticoduodenectomy.Results:The incidence of PD postoperative delayed hemorrhage was 8.81％ (45/511).Univariate analysis shows:Preoperative bilirubin levels,pancreatic fistula,biliary fistula,postoperative abdominal infection are all the meaningful related factors(P＜0.05).With the application of multivariate logistic regression analysis,pancreatic fistula (OR=2.158) and abdominal infection (OR=3.051) were independent risk factors for postoperative delayed hemorrhages (P＜0.05).Conclusion:Dealing with the postoperative complications of PD like pancreatic fistula,abdominal infection and others,early detection and rapid diagnosis and correct treatment can effectively reduce the incidence of delayed hemorrhage.

Objective Digital PCR ( dPCR ) was established to detect plasma epidermal growth factor receptor (EGFR) T790M mutation of non-small cell lung cancer (NSCLC) patients and was evaluated in terms of analytical performance and clinical application significance.Methods The specific primers and probes for EGFR T790M mutation and wildtype were designed to establish dPCR platform.Limit of blank, sensitivity and linearity of dPCR were evaluated by the detection of plasmids with different concentrations to set up optimal reporting system and reanalyzing process.The mutation of EGFR T790M in plasma and tissue samples from 10 patients with advanced NSCLC resistant to EGFR-TKI therapy who were enrolled in Zhongshan Hospital Fudan University from January 2014 to October 2015 were analyzed by dPCR and amplification refractory ( ARMS) , respectively.The consistency was evaluated between dPCR and ARMS by Chi-square test.The correlation of T790M abundance detected by dPCR between plasma and tissue samples was also analyzed by Peasrson correlation analysis.Results Limit of blank and sensitivity of dPCR was 10 copies and 0.01%, respectively.dPCR was evaluated as linear in the range of 0.01%-100%( Y=1.226X-3.984,R2 =0.999 ).The consistency between dPCR and ARMS of tissue samples was good ( kappa=0.80), while the positive rates of plasma T790M detected by dPCR was significantly higher than ARMS (50%vs 20%,P<0.05).It was found that T790M abundance detected by dPCR was highly correlated between lung cancer tissue and plasma ( R =0.923, P <0.05 ) using Pearson correlation analysis. Conclusions A new method of dPCR with high sensitivity and absolute quantification is established for the detection of EGFR T790M mutation in plasma from advanced NSCLC patients, which brings tumor liquid biopsy into real.It has the ability to provide the most direct and valuable guidance for clinicians to make decision on EGFR tyrosine kinase inhibitors therapy in patients with advanced NSCLC resistant to EGFR-TKI.

Objective To explore the application value of endoscopic ultrasonography (EUS) in the diagnosis of suspected obstructive jaundice in acute biliary pancreatitis and its effect on treatment outcomes. Methods Clinical data were retrospectively collected in 96 patients with acute biliary pancreatitis (ABP) who were suspected obstructive jaundice. Patients were divided into early EUS scanning group (EES) and delay EUS scanning group (DES). Clinical treatment results and test results were compared between the two groups. Results The diagnosis sensitivity, specificity, accuracy, positive predictive value and negative predictive value of EUS were 96.43 %, 82.5 %, 90.63 %, 88.52 % and 96.29 %. Early EUS scan with 72 h could identify the etiology of ABP and subsequent treatment based on the EUS can easily decrease the white blood cell count, percentage of neutrophils, total bilirubin and serum amylase (P < 0.05). The pain relief rate in EEI group after 1 week treatment was significantly higher than that in the DES group (87.50 % vs 66.67 %, P = 0.027) and average length of hospitalization was shorter [(12.70 ±2.10) d vs (14.10 ± 3.00) d, P = 0.006]. Delay EUS scan were likely to have higher white blood cell count and total bilirubin, meanwhile seemed to increase the organ failure rate and necrotic infection of the pancreas. Conclusion ABP with suspected obstructive jaundice should be considered to have endoscopy intervention. Results of EUS are the basis for treatment decision, which can avoid the unnecessary endoscopy treatment.

Objective To investigate the effect of interfering Hiwi gene on the apoptosis of MDA-MB-231 cells. Methods The mRNA and protein expression of Hiwi mRNA and its target protein were analyzed by qRT-PCR and Western Blot after transfection. MDA-MB-231 cells were divided into 6 groups according to the experimental design. Interference effects were screened as siRNA interference group (Hiwi10330 group), and then divided into 3 groups according to the experimental design: interference group, negative control group/NC, blank control group/Blank. The cell apoptosis rate was detected by flow cytometry after transfection. Results The expression of mRNA in the interference group was significantly lower than that in the siRNA group (P < 0.05), the expression of target protein of Hiwi gene was also significantly inhibited (P < 0.05). The apoptosis rate of MDA-MB-231 cells was significantly higher than that of NC and Blank groups (P<0.05). Conclusion The apoptosis rate of breast cancer cells MDA-MB-231 was significantly increased after siRNA targeting hiwi gene silencing.

Objective:To investigate the value of artificial intelligence (AI)-assisted quantitative measurement in evaluation of the dynamic changes of CT for COVID-19 pneumonia.Methods:The clinical and chest CT dynamic imaging data of 99 patients with confirmed COVID-19 pneumonia who were hospitalized in Wuhan Central Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology from January 15, 2020 to March 10, 2020 were retrospectively analyzed. According to the definitive diagnosis, the 99 patients were classified into common ( n=36), severe ( n=33) and critical ( n=30) type, the CT imaging findings of each type were analyzed, including CT basic signs, total volume of pneumonia lesions and percentage of pneumonia lesions of the total lung volume (volume ratio). AI software was used to quantitatively evaluate the dynamic changes of chest CT images. The quantitative indicators included CT peak time of lesions, total volume of lesions peak, volume ratio of lesions peak, maximum growth rate of total volume and maximum growth rate of volume ratio. Kruskal-Wallis rank sum test was used to compare the difference of quantitative indexes between the 3 types, and χ 2 test or Fisher exact probability test was used to compare the difference of qualitative indexes between the 3 types. Sequence measurement and scatter plots were used to show the evolution trend of the volume ratio of the three types of COVID-19 pneumonia lesions. The ROC curve was used to analyze the value of the volume ratio of pneumonia lesions and its maximum growth rate in predicting the conversion of common pneumonia to severe or critical pneumonia. Results:There were statistically significant differences in age and gender distribution among patients with common, severe and critical COVID-19 ( P<0.05), the age of severe and critical types were significantly higher than that of common type ( P<0.01). Compared with common [2.5 (1.0, 5.0) d] and critical type[2.5 (1.0, 4.0) d], the time from onset to the first chest CT scan of severe type was prolonged [5.0 (2.5, 8.0) d, P<0.01]. There were statistically significant differences in involvement of multiple lung lobes (20 cases, 29 cases, 25 cases, χ2=10.403, P=0.006) in patients with common, severe and critical COVID-19 at the first scan, the incidence of the involvement of multiple lung lobes in severe and critical types was significantly higher than that of common type ( P=0.002). The volume ratios of patients with common, severe and critical COVID-19 at the first scan were statistically significant [1.0% (0.2%, 4.7%), 9.30% (1.63%, 26.83%), 2.10% (0.64%, 8.61%), Z=14.236, P=0.001], and the volume ratio of severe type was significantly higher than that of common type ( P<0.001), there was no statistically significant difference between common type and critical type ( P=0.062). Follow-up CT showed that the pneumonia lesions showed a dynamic transformation of progress and recovery, and it was seen that the coexistence of multiphase lesions. The trend line in the scatter plot of the three types of COVID-19 pneumonia lesions showed that the lesions in the advanced stage developed from less to more. The lesion peak volume ratios of the common, severe and critical types were 9.75% (4.83%, 13.18%), 29.80% (23.99%, 42.36%) and 61.81% (43.73%, 72.82%), respectively, the difference was statistically significant ( Z=74.147, P<0.001). The maximum growth rates of lesion volume ratio were 1.27% (0.50%, 1.81%)/d, 4.39% (3.16%, 5.54%)/d and 6.02% (4.77%, 9.96%)/d, respectively, the difference was statistically significant ( Z=52.453, P<0.001). The peak times of lesions were 12.0 (9.0, 15.0) d, 13.0 (10.0, 16.0) d and 16.5 (12.0, 25.0)d, respectively, the difference was statistically significant ( Z=9.524, P=0.009). Taking the volume ratio of pneumonia lesion 22.60% and the maximum growth rate of the volume ratio 1.875%/d as the boundary value, the sensitivity of diagnosing common type to severe or critical type was 92.10% and 96.83%, and the specificity was 100% and 80.56%, respectively. The area under the curve was 0.987 and 0.925, respectively. Conclusions:The lesions of COVID-19 pneumonia show a similar parabolic change on CT imaging. The use of AI technology to dynamitcally and accurately measure the CT pneumonia lesion volume ratio is helpful to evaluate the severity of the disease and predict the development trend of the disease. Patients with a rapid growth of volume ratio are more likely to become severe or critical type.