[Risk factors for different types of hypospadias].

OBJECTIVE: To explore the risk factors for different types of hypospadias. METHODS: According to the 1∶1 ratio, we included hypospadias children in the case group and those without urinary abnormality as controls, all from the Third Affiliated Hospital of Zhengzhou University between October 2015 to October 2016. Using univariate and multivariate logistic regression analyses, we investigated the risk factors for hypospadias as well as for four different types of the disease. RESULTS: Among the 440 subjects, the risk factors for hypospadias included preterm birth, fetal growth restriction, rural residence of the mother, pregnancy age <20 or >35 years, primipara, maternal smoking (including passive smoking), oral progesterone, cold or fever during pregnancy, and exposure to high temperature in early pregnancy, while the protective factors included protein supplement in early pregnancy. The pregnancy age <20 or >35 years was the main risk factor for type I hypospadias; preterm birth, fetal growth restriction, rural residence of the mother, primipara, and maternal smoking (including passive smoking) during pregnancy were the risk factors for type Ⅱ; preterm birth, fetal growth restriction, rural residence of the mother, and exposure to high temperature in early pregnancy were those for type Ⅲ; and exposure to high temperature in early pregnancy and oral progesterone during pregnancy were those for type Ⅳ. CONCLUSIONS: The risk factors for hypospadias vary for different types, and therefore hypospadias-related clinical studies should be conducted and preventive measures should be taken accordingly. However, a larger sample size is needed to get more scientific and reliable results concerning the risk factors for different types of hypospadias.

[A Meta analysis of the efficacy of high-frequency oscillatory ventilation versus conventional mechanical ventilation for treating pediatric acute respiratory distress syndrome].

OBJECTIVE: To systematically assess the clinical efficacy of high-frequency oscillatory ventilation (HFOV) and conventional mechanical ventilation (CMV) for treating pediatric acute respiratory distress syndrome (ARDS). METHODS: Data from randomized controlled trials comparing HFOV and CMV in the treatment of pediatric ARDS published before July 2016 were collected from the Cochrane Library, PubMed, Medline, CNKI, and Wanfang Data. Literature screening, data extraction, and quality assessment were performed by two independent reviewers according to the inclusion and exclusion criteria. The selected studies were then subjected to a Meta analysis using the RevMan 5.3 software. RESULTS: A total of 6 studies involving 246 patients were included. The results of the Meta analysis showed that there were no significant differences between the HFOV and CMV groups in the in-hospital or 30-day mortality rate, incidence of barotrauma, mean ventilation time, and oxygenation index (P>0.05). However, compared with CMV, HFOV increased the PaO2/FiO2 ratio by 17%, 24%, and 31% at 24, 48, and 72 hours after treatment respectively, and improved oxygenation in patients. CONCLUSIONS: Although the mortality rate is not reduced by HFOV in children with ARDS, this treatment can result in significant improvement in oxygenation compared with CMV. Further large-sample, multicenter, randomized clinical trials will be required to draw a definitive conclusion.

Determination of injection molding process windows for optical lenses using response surface methodology.

This study focuses on injection molding process window determination for obtaining optimal imaging optical properties, astigmatism, coma, and spherical aberration using plastic lenses. The Taguchi experimental method was first used to identify the optimized combination of parameters and significant factors affecting the imaging optical properties of the lens. Full factorial experiments were then implemented based on the significant factors to build the response surface models. The injection molding process windows for lenses with optimized optical properties were determined based on the surface models, and confirmation experiments were performed to verify their validity. The results indicated that the significant factors affecting the optical properties of lenses are mold temperature, melt temperature, and cooling time. According to experimental data for the significant factors, the oblique ovals for different optical properties on the injection molding process windows based on melt temperature and cooling time can be obtained using the curve fitting approach. The confirmation experiments revealed that the average errors for astigmatism, coma, and spherical aberration are 3.44%, 5.62%, and 5.69%, respectively. The results indicated that the process windows proposed are highly reliable.