[Correlations of Birth Defects With Birth Weight and Gestational Age].

Objective To analyze the incidence rate of birth defects in infants born at different gestational ages and birth weights,so as to provide a basis for improving the surveillance system and reducing the incidence of birth defects. Methods Data of all perinatal infants born at and after 28 weeks of gestation and within 7 days after delivery in all the hospitals with the obstetrical department from October 1,2003 to September 30,2015 were collected. Results From 2003 to 2015,1 236 937 perinatal infants were monitored,including 10 619 with birth defects (incidence rate of 8.59‰).Among the infants with birth defects identified by the hospital surveillance system of birth defects in Xi'an during the study period,3 306,3 473,and 224 infants showed the birth weights less than 2 500 g,the gestational age within the range of [28,37] weeks,and the gestation age≥42 weeks,respectively.The low birth weight infants showed higher incidence rate of birth defects than the normal birth weight infants (χ2=37 097.79,P<0.001).The premature infants (gestational age<37 weeks) and postterm infants (gestational age≥42 weeks) showed higher incidence rates of birth defects than infants born at normal gestational age (χ2=24 998.24,P<0.001;χ2=196.40,P<0.001).The top five birth defects of low birth weight infants were congenital hydrocephalus,spina bifida,congenital heart disease,anencephaly,and cleft lip and cleft palate.The outcomes of birth defects in normal weight infants and low weight infants were mainly live births (68.60%) and stillbirths (54.72%),respectively,which showed a significant difference (χ2=647.59,P<0.001).The main outcomes of birth defects in the infants born at normal gestation age,postterm infants,and premature infants were mainly live births (77.38%),live births (83.93%),and stillbirths (57.79%),respectively,which showed significant differences (premature infants vs.infants born at normal gestation age: χ2=2 025.08,P<0.001;premature infants vs. postterm infants:χ2=245.39,P<0.001;infants born at normal gestation age vs.postterm infants:χ2=16.28,P=0.001). Conclusions Premature infants,low birth weight infants,and postterm infants showed significantly higher incidence rate of birth defects than the infants born at normal gestation age.The outcomes of birth defects had significant differences between low birth weight infants and normal birth weight infants,between premature infants and infants born at normal gestation age,between premature infants and postterm infants,and between infants born at normal gestation age and postterm infants.

[Multiple Correspondence of Abnormal Birth History with Genetic and Environmental Risk Factors].

Objective To investigate the multiple correspondence of genetic and environmental risk factors with abnormal birth history and provide a scientific basis for improving the birth defects surveillance system and reducing the incidence of birth defects. Methods Data were collected from all the perinatal infants from 28-week-old fetuses to 7-day-old infants born in all the hospitals with obstetrical department in Xi'an from 2003 to 2015. Results A total of 1 236 937 perinatal infants were surveyed,including 10 619 with birth defects.The average incidence rate of birth defects was 0.86% (0.70%-1.15%).Multiple correspondence analysis showed that the women who had had 1 or 2 children with birth defects were associated with the history of spontaneous abortion,family history of birth defects,and history of exposure to toxic and harmful substances.The women who had had 3 or more children with birth defects showed stronger association with family history of birth defects.The birth defects in women with history of spontaneous abortion (257/10 619) was ranked in the order of congenital heart disease,polydactyly,neural tube defects,congenital hydrocephalus,cleft lip with cleft palate,and simple cleft lip.The birth defects in women who had given birth to children with birth defects (135/10 619) followed the order of cleft lip with cleft palate,anencephaly,hydrocephalus,neural tube defects,cleft lip,and talipes equinovarus. Conclusions Abnormal birth history is associated with family history of birth defects and history of exposure to environmental risk factors.Giving birth to three or more children with birth defects is highly correlated with the family history of birth defects.

Prediction of metallic nano-optical trapping forces by finite element-boundary integral method.

The hybrid of finite element and boundary integral (FE-BI) method is employed to predict nano-optical trapping forces of arbitrarily shaped metallic nanostructures. A preconditioning strategy is proposed to improve the convergence of the iterative solution. Skeletonization is employed to speed up the design and optimization where iteration has to be repeated for each beam configuration. The radiation pressure force (RPF) is computed by vector flux of the Maxwell's stress tensor. Numerical simulations are performed to validate the developed method in analyzing the plasmonic effects as well as the optical trapping forces. It is shown that the proposed method is capable of predicting the trapping forces of complex metallic nanostructures accurately and efficiently.

Prediction of radiation pressure force exerted on moving particles by the two-level skeletonization.

A fast full-wave method for computing radiation pressure force (RPF) exerted by shaped light beams on moving particles is presented. The problem of evaluating RPF exerted on a moving particle by a single excitation beam is converted into that of computing RPF's exerted on a static particle by multiple beams. The discretization of different beams leads to distinct right hand sides (RHS's) for the matrix system. To avoid solving each RHS by the brute-force manner, the algorithm conducts low-rank decomposition on the excitation matrix consisting of all RHS's to figure out the so-called skeleton light beams by interpolative decomposition (ID). The peak memory requirement of the skeletonization is a bottle-neck if the particle is large. A two-level skeletonization scheme is proposed to solve this problem. Some numerical experiments on arbitrarily shaped homogeneous particles are performed to illustrate the performance and capability of the developed method.