OBJECTIVEThis study aims to identify the crack tip stress intensity factor of the propagation process, crack propagation path, and the changes in the shape of the crack tip by the finite element method.

METHODSThe finite element model of dentino-enamel junction was established with ANSYS software, and the length of the initial crack in the single edge was set to 0.1 mm. The lower end of the sample was fixed. The tensile load of 1 MPa with frequency of 5 Hz was applied to the upper end. The stress intensity factor, deflection angle, and changes in the shape of the crack tip in the crack propagation were calculated by ANSYS.

RESULTSThe stress intensity factor suddenly and continuously decreased in dentino-enamel junction as the crack extended. A large skewed angle appeared, and the stress on crack tip was reduced.

CONCLUSIONThe dentino-enamel junction on human teeth may resist crack propagation through stress reduction.

To cultivate nursing students with international professional ability for higher vocational education is the key to promote the internationalization of Chinese nursing field. Through analyzing the de-veloping trends and problems of international nursing education in China, based on the international nurses' ability, and study from the nurses training model of Philippines, the international nursing training model was constructed. The paper discussed the selection and retention of students, emphasizing the cultivation of students' international nursing concept and professional English, focusing on the ISPN curriculum and the integration of theory and practice, encouraging the cooperation of international school and faculties sharing, adapting the students-centered teaching methods, and establishing a corresponding sound evaluation system.

Objective:To construct of transfectant cells expressing ??TCR with specific CDR3 sequence.Methods:Specific CDR3 region sequence of DBS4.3,a known ??T cell clone,was inserted into ?9 and ?2 chain to substitute original CDR3 sequence using overlapping PCR method.After the full-length ?9 and ?2 chains were ligated with expression vector pREP7and pREP9 respectively,they were co-trasfected into a cell line of human Jurkat cells with TCR ? chain gene-defective mutant J.RT3-T3.5.When the transfectant cells expressing specific ??TCR were stimulated by antigen,production of IL-2 was detected by ELISA and Realtime PCR.Results:By ELISA and Realtime PCR,it was exhibited that the transfectant cells expressing DBS4.3 specific ??TCR secreted IL-2 under stimulation of iso-butylamine and anti ??TCR antibody.Conclusion:The transfectant Jurkat cells expressing ??TCR with specific CDR3 sequence are successfully constructed.It provides a platform for the research of recognition mechanism of ??TCR.

Objective To study the influence of minocycline combined with azithromycin on serum CRP, D-Dimer and lung function in the children with refractory mycoplasma. Methods From April 2015 to August 2016, 42 children with refractory mycoplasma pneumonia were enrolled in the second hospital in Tianjing. The patients were divided into the observation group and the control group according to the order of admission. The control group was treated with azithromycin sequential therapy, the observation group were given minocycline combined with azithromycin to complete the treatment. The levels of serum CRP, D-D, lung function, clinical symptoms and signs, and the adverse effects were observed. Results After treatment, the total effective rate of the observation group was significantly higher than that in the control group (P<0.05). The levels of CRP and D-D in the observation group were significantly lower than those in the control group (P<0.05). The highest expiratory flow velocity (PEE), first-second forced expiratory volume (FEV1), forced vital capacity (FVC) and forced expiratory 25% flow rate (MEF25) in the observation group were significantly higher than those in the control group (P<0.05). The time of X-ray recovery time, the time of fever, the time of cough and the disappearance of lung rales were significantly shorter than those in the control group (P<0.05). Compared with the control group, there were no significant differences in diarrhea, abdominal pain, nausea, vomiting, pleural effusion, otitis media, mild anemia and rash adverse reaction rate in the observation group. Conclusion Minocycline combined with azithromycin in the treatment of severe Mycoplasma pneumoniae pneumonia can effectively reduce serum levels of CRP and D-D, improve pulmonary function and clinical symptoms, and have good clinical efficacy.

OBJECTIVE:To systematically review the efficacy and safety of rosiglitazone and metformin in the treatment of type 2 diabetes,and provide evidence-based reference for the clinical treatment. METHODS:Retrieved from PubMed,Medline, EMBase,Cochrane Library,CJFD,VIP and Wanfang database,randomized controlled trials (RCT) about rosiglitazone (test group)and metformin(control group)in the treatment of type 2 diabetes. After data extract and quality evaluation,Meta-analysis was performed by using Rev Man 5.0 statistics software. RESULTS:A total of 5 RCT were included involving 636 patients. Re-sults of Meta-analysis showed the incidence of diarrhea [RR=0.23,95%CI(0.07,0.81),P=0.000] in test groupwere significantly lower than control group,the HbA1c level [MD=0.22,95%CI(0.07,0.38),P=0.004],the incidence of edema [RR=0.20,95%CI (0.05,0.57),P=0.011] in test group was significantly higher than control group,and there was no significant difference in the fast-ing blood glucose level[MD=0.27,95%CI(-0.26,0.79),P=0.32],the incidence of nausea/vomiting [RR=0.94,95%CI(0.06, 0.89),P=0.692]between 2 groups. CONCLUSIONS:Metformin is more effective than rosiglitazone in the treatment of type 2 dia-betes,however,the incidence of diarrhea should be noticed. Due to the limit of methodological quality and sample size,it remains to be further verified with more rigorously designed and long-term follow-up of large-scale RCT.

OBJECTIVE:To study the preventive and therapeutic effect and its mechanism of medicine pair decoction liquid of Curcuma phaeocaulis-Sparganium stoloniferum on rats with uterine myoma. METHODS:Rats were randomly divided into normal group,model group,positive group(mifepristone,2.25 mg/kg)and medicine pair decoction liquid group(C. phaeocaulis-S. stolon-iferum decoction liquid,6.0 g/kg),10 in each group. Except for the normal group,rats in other groups were injected Estradiol ben-zoate injection (0.5 mg/kg) intramuscularly every Monday,Wednesday and Friday,for 12 weeks. From the 13th week,rats in modeling group were added Progesterone injection(5 mg/kg)intramuscularly as well as relevant medicines intragastrically,once a day,until the 16th week. After administration,uterine coefficient of rats was detected. HE staining was used to observe the patho-logical changes of uterus and determine the thickness of smooth muscle;immunohistochemical staining was adopted to detect the transforming growth factor β3 (TGF-β3),matrix metalloproteinase 11 (MMP-11) protein expressions in uterus tissue of rats. RE-SULTS:Compared with normal group,uterine coefficient was increased in model group,pathological changes were obvious in uterus,thickness of smooth muscle was increased,TGF-β3 and MMP-11 protein expressions were enhanced(P<0.05 or P<0.01). Compared with model group,above-mentioned changes were improved significantly in positive group and medicine pair decoction liquid groups(P<0.05 or P<0.01). CONCLUSIONS:Medicine pair decoction liquid of C. phaeocaulis-S. stoloniferum shows cer-tain preventive and therapeutic effect on rats with uterine myoma. The mechanism may be associated with downregulating the TGF-β3,MMP-11 protein expressions in uterus tissue.

Objective To explore the effect of acupuncture on stroke patients in hemiplagic spasm period.Methods63 stroke patients in hemiplagic spasm period were randomly divided into the electro-acupuncture group(n=31) and control group(n=32).All patients of two groups received routine rehabilitation training,but those of the electro-acupuncture group were added with electro-acupuncture at "Zusanli"(ST36).The composite spasticity scale(CSS) score,H/Mmax and muscular compliance of two groups before and after treatment were observed and compared.ResultsThe CSS scores and H/Mmax and grading gastrocnemius muscular compliance of the electro-acupuncture group were superior to that of the control group(P<0.05～0.01).ConclusionAcupuncture can decrease muscular tension and increase motor function of stroke patients in hemiplagic spasm period.

Objective To explore the relationship between SNPs in microRNA binding sites of ABCG5/8 and the glucolipid level during pregnancy.Methods 1 925 pregnant women were recruited at Peking Union Medical College hospital from 2006 to 2011.The clinical data were collected and the total genomic DNA was extracted from whole blood samples.ABCG5/8, which was reported to be related with the glucose and lipid metabolism closely, were selected as the candidate gene and the SNPs in its microRNA binding sites with minor allele frequency >5% in Han Chinese in Beijing were chosen.Then the genotyping was performed and analyzed.Results There was only one SNP matching the criteria, rs2278356, and it is significantly associated with LDL-C and TC level during pregnancy (LDL-C: b=0.104 mmol/L, 95% CI 0.023-0.185 mmol/L, P<0.05;TC: b=0.105 mmol/L, 95% CI 0.080-0.203 mmol/L, P<0.05).Conclusions The association of rs2278356 in 3′UTR of ABCG5/8 with LDL-C and TC level in pregnant Chinese Han women is found, which may provide an individualized treatment strategy for pregnant women with high cholesterol.

Objective To explore the effect of low frequency repetitive transranial magnetic stimulation (rTMS) on unilateral spatial neglect (USN). Methods 40 stroke patients with USN were divided into treatment group (n=20) and control group (n=20). Patients in the treatment group were treated with low frequency rTMS for 2 weeks. The USN degree of these groups were evaluated before and after the treatment. Results There was no significant difference of USN degree between these groups before the treatment (P>0.05); Compared with the control group, the treatment group improved significantly after the treatment (P<0.05). The USN degree of patients in the treatment group decreased significantly after the treatment (P<0.05), while patients in the controlled group had no difference (P>0.05). Conclusion USN induced by stroke could be improved obviously through low frequency rTMS.

Objective:To investigate the incidence, drug sensitivity and drug resistance characteristies, and theraputic effect of staphylococcal peritoneal dialysis-associated peritonitis (PDAP), aim to provide clinical evidences for standardizing treatment therapy of staphylococcal PDAP. Methods:Clinical data of PDAP patients admitted to the Second Hospital of Jilin University, the First Hospital of Jilin University-the Eastern Division, Jilin Central Hospital and Jilin First Automobile Work General Hospital during January 1, 2013 and December 31, 2019 were retrospectively collected. The results of etiology, drug sensitivity and drug resistance of staphylococcal PDAP patients were collected. According to the pathogenic bacteria, patients were divided into staphylococcus aureus group ( n=48) and coagulase-negative staphylococcus group ( n=232). According to the results of methicillin resistance, patients were divided into drug-resistant group ( n=71) and drug-sensitive group ( n=30). The prognosis of antibiotic therapy in each group were compared. Poisson regression was used to test the changing trend of the incidence of staphylococcal PDAP. The changes of drug sensitivity and drug resistance of staphylococcus were compared between 2013 and 2019 by linear trend χ2 test. Results:A total of 1 085 cases of PDAP occurred in 625 patients were screened, and 280 cases of staphylococcal PDAP were finally included. The incidences of staphylococcal PDAP, staphylococcus aureus PDAP and coagulase-negative staphylococcal PDAP were 0.063 times per patient year, 0.010 times per patient year and 0.053 times per patient year respectively. In addition, the incidence of PDAP caused by staphylococcus, staphylococcus aureus and coagulase-negative staphylococcus decreased year by year (all P<0.05). With the change of years, the sensitivity rate of staphylococcus to rifampicin increased, while the sensitivity rate of staphylococcus to moxifloxacin decreased (both P<0.05). The drug resistance rate of staphylococcus to levofloxacin increased ( P<0.05). The staphylococcus aureus group was more prone to refractory PDAP and catheter removal than that in coagulase-negative staphylococcus group, and the recurrence rate was higher than that in coagulase-negative staphylococcus group (all P<0.05). The proportion of vancomycin used during the whole course of antibiotic therapy in drug-resistant group was higher than that in drug-sensitive group ( P<0.05). Conclusions:The incidence of staphylococcal PDAP decreases year by year, and the drug sensitivity characteristics of staphylococcus also change. The therapeutic outcomes of staphylococcus aureus PDAP are worse than that of coagulase-negative staphylococcus.