BACKGROUND: In the clinic, super-hard plaster is widely used for preparation of casts that can duplicate oral cavity situation, such as fixed denture and removable denture. The bending resistance of super-hard plaster can sufficiently resist the force to strip, which would avoid the fracture of tooth model. However, the symptom of tooth model fracture exists when hard material, such as polyether rubber, is used as impression material. OBJECTIVE: To compare the dimensional accuracy and bending resistance among four kinds of super-hard plaster: YCG, Dentona, Heraeus, and Huicheng. METHODS: Mental casts including three unit fixed bridge and cuboid (50 mm×10 mm×5 mm) were prepared and then poured with the above-mentioned four kinds of super-hard plaster. Then dimensional accuracy and bending resistance of the casts were measured through the use of universal tool microscope and universal testing machine. CONCLUSION AND RESULTS: The proximal-distal dimensional accuracy of YCG, Dentona, Heraeus, and Huicheng super-hard plaster casts was 15.043, 15.034, 15.037 and 15.040 mm, respectively, the buccolingual dimensional accuracy was 7.020, 7.015, 7.019, and 7.019 mm, respectively, the tooth long-axis dimensional accuracy was 8.022, 8.018, 8.019, and 8.02 mm, respectively. The bending resistance of the four super-hard plaster casts was 15.687, 13.000, 22.521, 18.675 MPa, respectively. There was no significant difference in dimensional accuracy (P > 0.05), but there was significant difference in bending resistance (P < 0.01), among these four super-hard plaster casts. The bending resistance of Heraeus super-hard plaster cast was significantly greater compared with the other 3 super-hard plaster casts (P < 0.01), and the bending resistance of Huicheng super-hard plaster cast was significantly greater than that of Dentona super-hard plaster cast (P < 0.01). These findings demonstrate that Heraeus super-hard plaster has the highest bending resistance, followed by Huicheng and YCG super-hard plaster casts, and lastly Dentona super-hard plaster cast. These findings suggest that super-hard plaster cast with greater bending resistance should be chosen as possible according to practical situation.

AIM: To observe the effect of ischemic preconditioning on contents of cytochrome C and mitochondrial calcium in rats after focal cerebral ischemic-reperfusion. METHODS: Focal cerebral ischemic model was made by occlusion of right middle artery in Wistar rats (ischemia for 2 h and reperfusion for 4 h). Rats were randomly divided into three groups: ischemia pretreatment, model and sham operation. Rats in ischemic pretreatment group were undergone transient ischemic preconditioning (30 min) and reperfusion (72 h). The contents of cytochrome C were measured according to Zhangjuntian's improved methods. The contents of mitochondrial calcium were detected by flame atom absorption. RESULTS: The contents of mitochondrial cytochrome C and calcium in model group were significantly lower than those in sham operation (P

AIM:To investigate the effect of batroxobin on thromboxane A 2(TXA 2)level in canine heart ischemia/reperfusion (I/R) injury and the cardioprotective mechanism of batroxobin against I/R injury. METHODS: Canine heart ischemia was induced by ligation of the left anterior descending coronary artery for 30 min followed by 90 min reperfusion.Batroxobin was intravenously administered before heart ischemia and 15 min before reperfusion.The level of plasma thromboxane (TXA 2) ,creatine phosphokinase (CK), lactic dehydrogenase (LDH ) and the concentration of myocardial TXA 2 were measured. The pathological changes in I/R myocardium were observed. RESULTS: In I/R group, TXA 2 levels of both plasma and myocardium increased significantly,and myocardium was injured obviously. Myocyte cells of central zone of I/R heart showed intracellular edema, swollen and damaged mitochondria, and fragmentation of cristae and concentrated nucleus. Plasma CK and LDH level was also elevated. Both ways of batroxobin administration reduced TXA 2 level apparently and plasma CK?LDH were also reduced significantly. LVEDP lowered while +dp/dt max elevated greatly,the mortality of I/R canine reduced obviously. CONCLUSION: Batroxobin decreased TXA 2 levels of both plasma and myocardium significantly, and could afford protection from I/R injury.

AIM: To study the cell apoptosis and the change of microstructure and ultrastructure in epididymis with experimental varicocele (EVC) in rats. METHODS: Experimental varicocele model was induced by partial ligation of the left renal vein in adolescent Sprague-Dawley Wistar rats. Apoptotic cells were detected by in situ terminal deoxynucleotityl transferase-mediated dTUP nick end labeling (TUNEL) technique. The corpus epididymis of the rats was prepared for light and electron microscopic observation. The microstructure and ultrastructure of the epididymis were studied. RESULTS: There was certain proportion of apoptosis cells in epididymis cells in control rats. The incidence of apoptosis increased remarkably in experimental group than that in control group (P

Objective In order to explore the influence and effect of case teaching method based on real patients in oto-rhinolaryngology on clinical practice ability of general practice.Methods 96 trainees of general practice in otolaryngology de-partment from January 2018 to January 2021 were randomly divided into two groups:a CBL group and a control group.In the CBL group,CBL teaching method was adopted based on real patients in Otorhinolaryngology.Conventional teaching method was used in the control group.Results The theoretical scores of written test and the examination of clinical skill operation scores of the CBL group and the control group were analyzed.There was significant difference between the two groups(P＜0.05).The students in CBL group were more satisfied with clinical thinking ability,analysis and problem solving ability,active learning abil-ity,learning efficiency,teacher-student interaction,doctor-patient communication ability and consultation skills than the control group.There was significant difference between the two groups(P＜0.05).Conclusion The CBL teaching method can obvi-ously improve the learning enthusiasm and clinical practice ability of general resident training doctors.The teaching quality has been significantly improved.It is of great value to cultivate excellent general practitioners.

Objective To establish a stably overexpressing miR-31 transgenic mouse and detect the expression of miR-31 in the organs and tissues,and to provide qualified tool mice with overexpression of miR-31 in vivo. Methods The miR-31 overexpression vector was constructed by Gateway cloning technology. The vector was injected into fertilized ovum by DNA microinjection technology,then transferred to the pseudopregnant mice and waited for eutocia. Newborn mouse tail DNA was extracted and PCR and agarose gel electrophoresis were performed to identify the positive miR-31 transgenic mice. microRNA was extracted from the organs and tissues of miR-31 transgenic mice and the expression of miR-31 was de-tected by RT-PCR. The expression of Nestin and number of neural stem cells in the nervous system were compared in the positive and WT mice. Results The miR-31 transgenic mice were constructed successfully and bred more than 14 genera-tions in barrier environment. Expression of miR-31 was increased in major organs and tissues. The expression of Nestin and the number of neural stem cells in the positive mice were higher than those in the wild type mice. Conclusions MiR-31 overexpressing transgenic mice are constructed by Gateway cloning technology and the expression of miR-31 is stable in sub-sequent generations. The number of neural stem cells in the nervous system is higher than that in wild-type mice. The miR-31 overexpressing transgenic mice can be a good tool for experimental research of the function of overexpressed miR-31 in vivo and the treatment of nervous system diseases.

ObjectiveTo investigate the risk factors of fertility behaviors with preterm birth and low birth weight， and to develop a nomogram model to predict the occurrence of low birth weight. MethodsBirth registration information in Shanghai from 2010 to 2020 was collected， and ANOVA and Chi-square tests were used to compare the differences in reproductive behavior factors and newborn health status across time. The odds ratio （OR） value and 95%CI were calculated by a multi-classification logistic regression model to determine the association between reproductive behavior factors and preterm birth or low birth weight infants. A nomogram model was established based on logistic model and the area under the ROC curve was used to assess the effect of the model. ResultsThis analysis included 2 089 384 live newborns. The incidence of full-term low birth weight， preterm normal weight and preterm low birth weight in Shanghai was 0.94%， 2.48% and 2.01%， respectively. From 2010 to 2020， 40.00% women had a history of abortion， the proportion of women who gave birth at age ≥40 years old increased from 1.05% to 2.24%， the proportion of fathers aged ≥40 years increased from 4.79% to 7.48%， and the proportion of women with postgraduate or above increased from 4.81% to 11.74%. The incidence of preterm low birth weight in Shanghai showed an increasing trend over time. Logistic regression analysis showed that the risk of preterm low birth weight was lower in female than in male infants （OR=0.97， 95%CI： 0.95‒0.98）， and the risk of full-term low birth weight was higher than in male infants （OR=1.85， 95%CI： 1.80‒1.90）. The risk of preterm birth and low birth weight was lower for couples of childbearing age with higher education. The risk of preterm low birth weight in newborns tended to increase with maternal age at childbirth >30 years， paternal age ≥40 years， and the number of abortions >2 times. Mother <25 or >35 years， father aged 30‒34 years， and the number of abortions >3 times were the risk factors of full-term low birth weight infants. ConclusionCouples of childbearing age who choose to have children at too high or too low age may increase the risk of preterm birth or low birth weight， so it is necessary to strengthen population awareness and promote age-appropriate childbirth. Multiple abortions are also associated with preterm birth and low birth weight， and it is advisable to popularize the scientific knowledge of contraception and birth control to reduce unnecessary abortions. The nomogram in the study can visualize the risk of full-term and low birth weight infant at different levels of factors， which can assist couples preparing for pregnancy in making decisions about the timing of childbirth and understanding the level of risk.

Background and purpose:The Shanghai Municipal Center for Disease Control and Prevention provides annual updates on cancer occurrence and trends in Shanghai.This study aimed to investigate the cancer incidence and mortality in 201 7 and their trends from 2002 to 2017 in Shanghai. Methods:Data of new cancer diagnoses and deaths from 2002 to 2017 were obtained from the Shanghai Municipal Center for Disease Control and Prevention population-based cancer registry and Vital Statistics System.Cancer incidence and mortality stratified by year of diagnosis or death,gender and age group were analyzed.Number,proportion,crude rate,age-specific rate,age-standardized rate and others were calculated.The number,proportion and rates of common cancers in different groups were also calculated.Trends in age-standardized rate of incidence and death rates for all cancers combined and for the common cancer types by gender were estimated by joinpoint analysis and characterized by the annual percent change(APC)and average annual percent change(AAPC).Segi's 1960 world standard population was used for calculating age-standardized incidence and mortality. Results:The new cancer cases and deaths were 79 378 and 37 186 in Shanghai in 2017.The crude rate of incidence was 546.55/105,and the age-standardized rate was 246.31/105.The age-standardized rate of incidence was higher among females than among males.The crude rate of mortality was 256.04/1 05,and the age-standardized rate was 88.41/105.The age-standardized rate of mortality was higher among males than among females.The age-specific numbers and rates of incidence and mortality increased with age.The age-specific number and rate of incidence reached the peak at the age groups of 60-64 years and older than 85 years,and those of mortality among males reached the peak at the age groups of 60-64 years and older than 85 years,and those of mortality among females reached the peak at the age groups of older than 85 years,respectively.The sites of top 10 common cancer types sorted by the number of incidence cases among males were lung,colorectum,stomach,prostate,liver,thyroid,pancreas,bladder,kidney and oesophagus,and among females were lung,breast,thyroid,colorectum,stomach,pancreas,liver,brain,central nervous system(CNS),cervix uteri and gallbladder,the sites of those sorted by the number of deaths among males were lung,stomach,colorectum,liver,pancreas,prostate,oesophagus,bladder,lymphoma and gallbladder,among females were lung,colorectum,breast,stomach,pancreas,liver,gallbladder,brain,CNS,ovary and lymphoma.The top 10 common cancer types stratified by gender and the top 5 common cancer types stratified by common age groups merged of incidence and mortality had wide variations.Overall,the age-standardized rates of incidence were stable from 2002 to 2009,and increased 2.88％on average per year from 2009 to 201 7.The age-standardized rates of mortality were stable from 2002 to 2011,and decreased 2.66％on average per year from 2011 to 201 7.The trends differed by gender and cancer type. Conclusion:Lung cancer,colorectal cancer,pancreatic cancer,thyroid cancer,female breast cancer,cervical cancer and male prostate cancer are the most common cancers in Shanghai,the appropriate screening technical scheme should be formulated according to the current situation of malignant tumors in Shanghai,promote cancer opportunistic screening,promote appropriate technologies for intervention and management of cancer patients in the community,reduce the disease burden of malignant tumors.

Objective:To investigate the survival of cancer cases diagnosed during 2002-2013 in Shanghai. Methods:Data on new cancer cases with dead and follow-up information were obtained from the population-based cancer registry and vital statistics system of Shanghai Municipal Center for Disease Control and Prevention.Survival indicators stratified by year of diagnosis,gender,site and age were analyzed.Number of cases and proportion were calculated.The observed survival rates were calculated based on the life table.The probabilities of surviving from 0 to 99 years old were estimated according to the Elandt-Johnson model,and then the cumulative expected survival rates were calculated according to the Ederer Ⅱ method.Finally,the relative survival rates and average annual percent changes of their trends were calculated.The age-standardized relative survival rates adjusted by International Cancer Survival Standard weights were calculated. Results:Total 644 520 new cancer cases were diagnosed during 2002-2013 in Shanghai,accounting for 643 545(99.85％)cases included in the observed cohort for survival analysis.The 5-year observed survival rate increased from 37.61％to 46.47％.The 5-year relative survival rate increased from 42.1 8％to 51.11％.The 5-year age-standardized relative survival rate increased from 40.57％to 49.80％.Among the 5-year relative survival rates of cases diagnosed during 2011 to 2013,99.43％of thyroid cancer was the highest,followed by female breast cancer(88.35％)and corpus uteri cancer(85.56％);5.87％of pancreas cancer was the lowest,followed by gallbladder cancer(13.64％)and oesophagus cancer(17.72％).the rate of lung cancer with the largest number of cases was 23.59％,followed by colorectal cancer(59.82％)and stomach cancer(38.65％).The 5-year relative survival rate of total cases of all sites increased from 40.55％in 2002 to 52.77％in 2013,with an average annual percent change of 2.40％.13 cancer types showed increasing trends,such as liver cancer and lung cancer,while the trends of other cancer types were not statistically significant,such as pancreatic cancer and gallbladder cancer. Conclusion:The diagnostic levels and survival rates of cancer cases have been improved continuously in Shanghai.The trends of different cancer types were varied.

Objective:To investigate the lung cancer incidence and mortality in 2016 and their trends from 2002 to 2016 in shanghai. Methods:The data of incidence and death on lung cancer in shanghai from 2002 to 2016 were obtained from the Shanghai Municipal Center for Disease Control and Prevention population-based cancer registry and Vital Statistics System.Lung Cancer incidence and mortality stratified by age of diagnosis or death,gender and age-group were analyzed.The number of cases and deaths,proportion,crude rates,age-specific rates,age-standardized rates,corresponding truncated age-standardized rates(35-64 years)and cumulative rates were calculated.Segi's 1960 world standard population was used for calculating age-standardized rates of incidence and mortality as well as truncated age-standardized rates.Trends in age-standardized rates of incidence and death for lung cancer in Shanghai from 2002-2016 were estimated by Joinpoint analysis and characterized by the annual percent change(APC). Results:The new lung cancer cases and deaths were 14 395 and 9 170 in Shanghai in 2016.The crude rate of incidence was 99.41/105,and the age-standardized rate of incidence was 39.76/105.New cases of lung cancer accounted for 19.34％of all malignant tumors in shanghai,ranking the first in the incidence spectrum of malignant tumors.The crude rate of mortality was 63.33/105,and the age-standardized rate was 21.57/105.Deaths of lung cancer accounted for 24.78％of all malignant tumor deaths in shanghai,ranking the first in the mortality spectrum of malignant tumors.The age-standardized rates of incidence and mortality for males were higher than those for females.The age-specific numbers and rates of incidence and mortality increased with age.The age-specific number and rate of incidence reached the peak at the age group of 60-64 years and 80-84 years respectively,and those of mortality peaked at the age group of 80-84 years and older than 85 years respectively.The incidence of lung cancer increased from 33.70/105 in 2002 to 39.76/1 05 in 2016 in Shanghai.Joinpoint analyses showed that the age-standardized rate of lung cancer incidence remained stable from 2002 to 2010(APC=-0.79,t=-1.46,P=0.175)but showed a significant upward trend with an average annual increase rate of 5.12％from 2010 to 2016(APC=5.12,t=6.97,P＜0.001).The standardized mortality showed a downward trend with an average annual decrease rate of 0.87％from 2002 to 2016(APC=-0.87,t=-2.87,P=0.013). Conclusion:The incidence of lung cancer in Shanghai during 2002-2016 presented an upward trend while the mortality of lung cancer showed a gradual downward trend.There are differences in the incidence and mortality of lung cancer among different gender and age groups.