ABSTRACT
<p><b>BACKGROUND</b>To investigate the incidence and risk factors of retinopathy of prematurity (ROP) in two Neonatal Intensive Care Units in North and South of China, respectively.</p><p><b>METHODS</b>We studied data concerning 472 infants with gestational age (GA) ≤ 34 weeks or birth weight (BW) ≤ 2000 g who were admitted to the Zhujiang Hospital of Southern Medical University and the Fourth Hospital of Shijiazhuang between January 1, 2011 and December 31, 2011. Clinical information about perinatal neonates was collected and was confirmed by reviewing medical charts. The incidence and severity of ROP were assessed in the screened population. Main outcome measures are the incidence and severity of ROP. The relationship of clinical risk factors and the development of ROP were analyzed.</p><p><b>RESULTS</b>The overall incidence of ROP was 12.7%, and the overall incidence of type 1 ROP was 2.3%; 9.4% of infants in Zhujiang Hospital had ROP compared to 15.0% infants in the Fourth Hospital of Shijiazhuang developed ROP, and the difference is statistically significant. ROP was significantly associated with GA (odds ratio [OR]: 0.77 [0.62-0.95], P = 0.015), BW (OR: 0.998 [0.996-0.999], P = 0.008), maternal supplemental oxygen administration before and during delivery (OR: 4.27 [1.21-15.10], P = 0.024) and preeclampsia (OR: 6.07 [1.73-21.36] P = 0.005). The risk factors for ROP are different in two hospitals. In Zhujiang Hospital, BW is the independent risk factors for ROP while GA, BW and preeclampsia in the Fourth Hospital in Shijiazhuang Conclusions: Retinopathy of prematurity incidence is different based on area. Incidence of ROP is still high in China. More efforts need to prevent ROP.</p>
Subject(s)
Female , Humans , Infant, Newborn , Male , China , Intensive Care Units, Neonatal , Retinopathy of Prematurity , Epidemiology , Risk FactorsABSTRACT
<p><b>OBJECTIVE</b>To analyze the stress distribution of bone around the dental implants with lateral immediate loading of different angles by three dimensional finite element.</p><p><b>METHODS</b>An adult edentulous mandible was adopted for CT scanning. The CT image was imported to universal surgical integration system to establish a mandible three dimensional mesh model. The real shape of standard thread implant was simulated and the finite element model of mandible with dental implants for immediate loading was established. The models were immediately loaded with 150 N through the angle of 0 degrees, 10 degrees, 20 degrees, 30 degrees. The ANSYS 10.0 was used to analyze the Von Mises stress on the bone around dental implants.</p><p><b>RESULTS</b>The accurate finite element model of mandible with dental implants for immediate loading was successfully established. The three dimensional finite element analytical results showed: Under axial load, the Von Mises stress of bone contact surface concentrated on the cortical bone of the implant cervix. The strain distribution was even, and centralized at the cortical bone of the implant cervix, cancellous bone of implant bottom and thread contact area. Under different lateral angle load, the Von Mises stress of bone contact surface also concentrated on the cortical bone of the implant cervix, but the maximum value was 4 times of the vertical loading, the strain distributed unevenly, mainly concentrated on the cortical bone of the implant cervix. With the load angle increased, the stress and the strain value also increased.</p><p><b>CONCLUSION</b>When an axial force was immediately loaded, the stress value and the strain concentration value of bone interface around the dental implants are not apparently concentrated, the stress is distributed well. While a lateral force is loaded, the stress values and the strain concentration values of bone interface around the dental implants apparently increase and the strain are distributed unevenly.</p>