BACKGROUND:Biomechanical compatibility is the necessary condition to ensure the stable osseointegration with implants that then can function over a long period; therefore, it is especialy important to get knowledge about distribution of stress and strain between the maxilary central incisor and its surrounding bone tissue. OBJECTIVE: Based on five different anatomical types of natural teeth, to study the regularity of stress distribution between the maxilary central incisor root and implant.METHODS: According to the five different anatomical types of natural maxilary central incisors, UGNX and ANSYS were used to set up three-dimensional finite element models (B1, B2, M1, M2, P1) for the implant and surrounding structures, which were under 100 N static load at angles of 0o, 30o, 45o, 60o, 90o with the long axis of teeth. Then, the stress distribution between the five kinds of maxilary central incisor roots and implants was analyzed. RESULTS AND CONCLUSION:Among the five different anatomical types, the equivalent stress for both the natural central incisor and implant were increased with the increasing of angles, and the implant had a higher raising trend. The equivalent stress for the natural tooth concentrated upon B1 for the maximum value and M1 for the minimum value; while the equivalent stress for the implant focused on the maximum value at M1 and the minimum value at M2. There was a gap of 2%-31% between the equivalent stresses for the natural tooth roots and a gap of 4%-21% for the implants. The stress distribution range for the implant was just smaler than that for the natural tooth roots. It implies that the bit force of implant and natural tooth is in positive proportion to the bite angles, and the bite force that implant can burden is smaler than that the central incisor can.

Objective To explore the clinical characteristics of late-onset ornithine carbamoyltransferase deficiency (OTCD) in order to improve the clinicians' understanding of this disease.Methods The clinical,therapeutic and follow-up data of two patients with late-onset OTCD diagnosed in the Department of Neurology,Qilu Hospital of Shandong University from November 2017 to February 2018 were collected and analyzed.Results Case 1 is a 17-year-old male who was admitted into Qilu Hospital with recurrent dizziness and vomiting for 4 months,sudden mental abnormality and convulsion for 3 days.The liver dysfunction,respiratory alkalosis and hyperammonemia (434 μmol/L) had been found before his admission.His blood ammonia fluctuated obviously from 180 μ mol/L to 2998 μmol/L,though he was given hemodialysis and arginine infusion,and died on the fourth day after admission.Case 2 is a 15-year-old male,complained with recurrent dizziness,vomiting,bluntness and somnolence for 20 days.He was found with hyperammonemia (600 μmol/L) and liver dsyfunction in a local hospital.He was getting better after intravenous administration of arginine and liver protective drugs.After admission,the blood ammonia,liver function and amino acids,acylcarnitine profiling in dried blood spots,and organic acid analysis in urine were normal,and he has not recurred since restriction of protein diet.Brain magnetic resonane imaging of both patients showed cytotoxic edema of bilateral frontal lobe and insular cortex,and their genetic detection both showed c.119G＞A(p.R40H) hemizygous pathogenic mutation of OTC gene inherited from their respective mothers.Conclusion Unexplained hyperammonemia and acute encephalopathy with insular and frontal cortical involvement should be on the alert to the urea cycle disorders,especially OTCD.Early diagnosis and reasonable treatment are the key to changing the prognosis.

Objective: To explore the application and effect evaluation of the new teaching mode of medical nursing based on mobile teaching platform. Methods: Taking 110 nursing undergraduates from 2015 grade as the control group, 105 nursing undergraduates from 2016 grade were selected as the experimental group. On the basis of the traditional classroom teaching method, the "teaching online" mobile teaching platform was designed and constructed by using WeChat. At the same time, the instructors of internal science theory were invited to join the platform to simultaneously synchronize online teachers, teachers and students, and upload teaching resources. The final examination results of the two groups were compared, and the satisfaction of nursing undergraduates with the teaching of internal medicine nursing was investigated at the end of the semester, and the difference between the new teaching mode and the traditional teaching mode was demonstrated through a comparative study. At the same time, through questionnaires, we can understand the satisfaction of teachers and students in assisting teaching on mobile teaching platforms. Results: The teachers and students had a positive attitude towards the application of mobile teaching platform to assist teaching and platform functions. 6/7 of teachers and 94.3% (99/105) of students supported the promotion of this auxiliary teaching mode. All teachers and most students (92.4%, 97/105) evaluated the participation of teachers in internal medicine theory to improve the teaching effect. After the application of "teaching online" mobile teaching platform, the satisfaction of nursing undergraduates with internal medicine nursing teaching was obviously improved, the overall evaluation of teaching satisfaction in the control group and the experimental group were (4.00±0.42) and (4.83±0.42) points (t =-22.306, P<0.01). The average scores of the final exam in the experimental group (80.90±5.11) points was significantly higher than (74.86±7.37) points in the control group (t=-7.000, P<0.05). Conclusion The interdisciplinary joint teaching model based on mobile teaching platform can stimulate the students′ enthusiasm for learning and improve teaching satisfaction and learning effect.