Objective:In order to optimize the crystallization technics, the effects of heat-treatment on the flexible strength and microstructure of a novel dental mica glass-ceramic were studied in present study. Methods:7 groups were treated respectively with different crystallization temperature and different crystallization time.Then the flexible strength, X-ray diffraction (XRD)and scanning electron microscope(SEM) were used to study the flexible strength and microstructure of such a novel dental mica glass-ceramic. Results: The result of the study indicated that along with the rise of crystallizing temperature and crystallizing time, this dental mica glass-ceramic showed the peak of bending strength (173.68 MPa) at 680 ℃ for 120 min.Conclusion:This material is promising as esthetic all-ceramic dental material.

Objective A comparison of two method of establishing pressure ulcer rat models to determine which is the most suitable for experimental use.Methods 18 male SD rats were randomly divided into control(n=6),model A(n=6)and model B(n=6)groups.In the control group,iodophor treatment was given after hair removal at the simulated modeling site.In model group A,longitudinal compression was performed by simple deep-tissue foreign body implantation.In model group B,transverse compression was performed via the magnet compression method.The times required to complete the process and for each stage of pressure ulcer model establishment in each group were recorded.The general condition of the rats was observed,and the modeling rate,mortality rate,and infection rate were compared.Results By naked eye,we observed that the model A and model B groups gradually developed redness and swelling,ulceration,bleeding,exudation,and necrosis.Comparison of the whole time to produce pressure uler between model A and model B groups:the difference between the two groups was statitically significant(P＜0.05).Comparison of the time to produce pressure injury between Model A and Model B:The difference between the two groups at stage Ⅰ was not statistically significant(P＞0.05);the difference between the two groups at stage Ⅱ was statistically significant(P＜0 05);the difference between the two groups at stage Ⅲ was statistically significant(P＜0 05);the difference between the two groups at stage Ⅳ was statistically significant(P＜0 05).The mental and sports scores of the rats in the control group were significantly different from those in the model A and model B groups(P＜0.05).The general state of rats in the model group A was significantly different from that in the model B group,and coat color was dimer and activity decreased in the model group A.The modelling rate of rats in both model A and model B groups was 100％.The mortality and infection rates of the model group A were higher than those of the model group B,which were 33.34％and 16.70％,respectively.Conclusions Successful preparation of a four-stage model of pressure ulers in both modalities.The two method have both commonalities and distinct characteristics.The magnet compression method required less time,the rats were generally in good condition,and the mortality and infection rates were low;thus it is suitable for short-term intervention research.The simple deep-tissue foreign body implantation method took longer,required rats to have a certain level of tolerance,had high infection and mortality rates,and is more suitable for use for long-term observations of pressure ulcers.

Objective To systematically review the worldwide simulation model studies on the natural history of breast cancer and to summarize related parameters.Methods A structured literature search was conducted in PubMed and the Cochrane Library to identify articles during 1980-2015.Articles were screened independently by two researchers.Health states in the natural history and relevant parameters were extracted.Results A total of 36 studies were included for analysis,within the earliest one was published in 1990.Most studies were from Europe and America countries,and 2 studies from China.Markov model was mostly applied to evaluating breast cancer screening programs (n=32).Reported health status included “healthy” (n=36),ductal carcinoma in situ (DCIS,n=17),invasive breast cancer (IBC,n=36),and death (n=27).There were two definite classifications for IBC,tumor size (n=9) and TNM staging (n=9,3 studies reported transition rates).The median (range) of annual transition rates from DCIS to stage-I IBC,I to Ⅱ,Ⅱ to Ⅲ,Ⅲ to Ⅳ were 0.279 (0.259-0.299),0.150 (0.069-0.430),0.100 (0.060-0.128) and 0.210 (0.010-0.625),respectively.A total of 15 studies reported the mean duration from predinical to clinical stage for IBC was 1.95-4.70 years,which gradually increased with age,and 7 studies reported that for DCIS.Conclusions Despite closer attention was paid to breast cancer natural history models,in recent years atypical hyperplasia has been neglected.Data on the mean duration of DCIS requires reasonable conversion.Various classifications for IBC exist whereas transition rates are limited.Current findings would be valuable references but challenging for the Chinese-population specific natural history model,development.

Objective: To parameterize the 1-year transition probabilities between different health status of the natural history of breast cancer based on the data of randomized controlled trial of X-ray mammography screening worldwide. Methods: Based on the breast cancer screening randomized controlled trials defined by a mammography screening review from the Cochrane 2013 and the International Agency for Research on Cancer, a systematic review was initiated in PubMed by searching names of the key investigators of the trials, combined with the diseases, screening intervention and outcome indicators. If applicable, all the original cumulative incidence rates were converted into one-year transition rate, using the life-table approach considering time length of follow-up. Results: A total of 23 reports from 9 RCTs were included. The data on transition rate between the healthy status to precancerous lesions was absent. The 1-year transition rate from health to carcinoma in situ was 17.78 to 50.21 per 100 000 persons in the intervention group and 9.16 to 26.84 per 100 000 persons in the control group. Correspondingly, the 1-year transition rate from health to breast cancer (including carcinoma in situ and invasive cancer) were estimated as 143.75 to 316.97 per 100 000 persons in the intervention group, and 141.45 to 288.84 per 100 000 persons in the control group. Furthermore, the transition rate from the healthy status to invasive breast cancer was 159.79 to 264.60 per 100 000 persons in intervention group and 170.12 to 255.33 per 100 000 persons in control group. The transition rate from carcinoma in situ to invasive breast cancer varied among different pathological types. Conclusions The most common natural history states of reported by the included trials involved the full healthy status, carcinoma in situ and invasive breast cancer. The findings of transition rates between different health statuses will be informative for future model development of natural history studies of breast cancer. Information in relation to breast precancerous lesions still limited and needs to be further addressed.